A Common View of the Opportunities, Challenges, and Research Actions for Pongamia in Australia

Abstract

Interest in biofuels is increasing in Australia due to volatile and rising oil prices, the need to reduce GHG emissions, and the recent introduction of a price on carbon. The seeds of Pongamia (Millettia pinnata) contain oils rich in C18:1 fatty acid, making it useful for the manufacture of biodiesel and other liquid fuels. Preliminary assessments of growth and seed yield in Australia have been promising. However, there is a pressing need to synthesise practical experience and existing fragmented research and to use this to underpin a well-founded and co-ordinated research strategy to support industry development, including better management of the risks associated with investment. This comprehensive review identifies opportunities for Pongamia in Australia and provides a snapshot of what is already known and the risks, uncertainties, and challenges based on published research, expert knowledge, and industry experience. We conclude that whilst there are major gaps in fundamental understanding of the limitations to growth of Pongamia in Australia, there is sufficient evidence indicating the potential of Pongamia as a feedstock for production of biofuel to warrant investment into a structured research and development program over the next decade. We identify ten critical research elements and propose a comprehensive research approach that links molecular level genetic research, paddock scale agronomic studies, landscape scale investigations, and new production systems and value chains into a range of aspects of sustainability.

Full text

A Common View of the Opportunities, Challenges,
and Research Actions for Pongamia in Australia
Helen T. Murphy &Deborah A. O’Connell &
Gary Seaton &R. John Raison &Luis C. Rodriguez &
Andrew L. Braid &Darren J. Kriticos &Tom Jovanovic &
Amir Abadi &Michael Betar &Heather Brodie &
Malcolm Lamont &Marshall McKay &
George Muirhead &Julie Plummer &Ni Luh Arpiwi &
Brian Ruddle &Sagun Saxena &Paul T. Scott &
Colin Stucley &Bob Thistlethwaite &Bradley Wheaton &
Peter Wylie &Peter M. Gresshoff
#Springer Science+Business Media, LLC 2012
Abstract Interest in biofuels is increasing in Australia due to
volatile and rising oil prices, the need to reduce GHG emis-
sions, and the recent introduction of a price on carbon. The
seeds of Pongamia (Millettia pinnata) contain oils rich in
C18:1 fatty acid, making it useful for the manufacture of
biodiesel and other liquid fuels. Preliminary assessments of
growth and seed yield in Australia have been promising.
However, there is a pressing need to synthesise practical expe-
rience and existing fragmented research and to use this to
underpin a well-founded and co-ordinated research strategy
to support industry development, including better management
of the risks associated with investment. This comprehensive
review identifies opportunities for Pongamia in Australia and
provides a snapshot of what is already known and the risks,
H. T. Murphy (*)
CSIRO Ecosystem Sciences, Tropical Forest Research Centre,
PO Box 780, Atherton, QLD 4883, Australia
e-mail: Helen.Murphy@csiro.au
D. A. O’Connell :R. J. Raison :L. C. Rodriguez :A. L. Braid :
D. J. Kriticos :T. Jovanovic
CSIRO Ecosystem Sciences,
GPO Box 1600, Canberra, ACT 2601, Australia
G. Seaton :G. Muirhead
Bioenergy Plantations Australia,
PO Box 1127, Caboolture, QLD 4510, Australia
A. Abadi
CRC Future Farm Industries, University of Western Australia,
Nedlands, WA 6907, Australia
M. Betar
Standard Commodities Group,
Suite 101, 274-290 Victoria Street,
Darlinghurst, NSW 2010, Australia
H. Brodie
Biofuels Association of Australia,
28 Elaroo Street,
Morningside, QLD 4170, Australia
M. Lamont :B. Thistlethwaite
PolyGenomX Ltd,
Level 4, 130 Bundall Road,
Bundall, QLD 4217, Australia
M. McKay
Australian PhytoFuel Company,
95 Simpsons Road,
Bardon, QLD 4065, Australia
J. Plummer :N. L. Arpiwi
Plant Biology, Faculty of Natural & Agricultural Sciences,
University of Western Australia,
35 Stirling Hwy,
Crawley, WA 6009, Australia
B. Ruddle
Rudco Pty Ltd,
Level 1, 686 Sherwood Road,
Sherwood, QLD 4075, Australia
S. Saxena :B. Wheaton
CleanStar Ventures,
Level 29, The Chifley Tower, 2 Chifley Square,
Sydney, NSW 2000, Australia
Bioenerg. Res.
DOI 10.1007/s12155-012-9190-6

uncertainties, and challenges based on published research,
expert knowledge, and industry experience. We conclude that
whilst there are major gaps in fundamental understanding of
the limitations to growth of Pongamia in Australia, there is
sufficient evidence indicating the potential of Pongamia as a
feedstock for production of biofuel to warrant investment into
a structured research and development program over the next
decade. We identify ten critical research elements and propose
a comprehensive research approach that links molecular level
genetic research, paddock scale agronomic studies, landscape
scale investigations, and new production systems and value
chains into a range of aspects of sustainability.
Keywords Oil seed .Pongamia .Millettia .Karanja .Yield .
Growth
Introduction
Interest in use of biomass for liquid fuels, electricity, and other
products is increasing in Australia due to volatile and increas-
ing oil prices, the pressing need to reduce GHG emissions, and
the introduction of a price on carbon. Current production of
plant-based oils in Australia is relatively small and could only
make a very small contribution to demand for liquid fuels [21,
44]. Many options are being explored to develop new capacity
to produce plant-based oils, including those based on algae and
oilseed.
Pongamia (Millettia pinnata, formerly known as Ponga-
mia pinnata) is an arboreal legume belonging to the family
Papilionoideae. The Pongamia tree has traditionally been
utilised for medicines, fodder, beautification, and shade.
Pongamia oil has long been used for lanterns and cooking
stove fuel and is currently of major interest for biofuel
production [30,41,59]. The seeds contain about 40%
extractable oil depending on the extraction method, i.e.,
either solvent (hexane) extraction or cold pressing [4,40,
66]. The oil is rich in C18:1 fatty acid (oleic acid) and has
relatively low amounts of palmitic and stearic acid, making
it useful for the manufacture of biodiesel [30,61]. The
presence of toxic flavonoids makes the oil non-edible [38].
Preliminary research on the potential for Pongamia culti-
vation in Australia has been promising [30,59], but research
and development effort is highly fragmented, operating at
small scales, and usually underfunded [53]. Recent attempts
to estimate the production potential of Pongamia at a national
scale [21,34,46] have found that whilst suitable growing
areas for Pongamia could be broadly modelled using a climate
matching approach, there is insufficient published or reliable
information relevant to Australia to provide quantitative rela-
tionships between genetics, growing environment, seed set,
and oil yield. The recent failure of Jatropha spp., another
oilseed candidate [29] widely planted in Asia and Africa for
biodiesel, clearly demonstrates the risks of embarking upon a
large-scale investment and planting program without first
conducting the sort of R&D program described in this paper.
Widespread optimism over potential oil yields (which have
mostly not been realised), and massive investment in planting
programs without a solid R&D foundation, has resulted in
enormous economic losses to investors in the Jatropha indus-
try. In particular, a lack of knowledge about the environment×
genetic× yield relationship in Jatropha is considered a key
driver of widespread crop failure [6,29]. There is a clear need
to consolidate current knowledge and attract the requisite
quantum of investment in research and development to un-
derpin industry development for Pongamia in Australia.
This paper has been prepared by the representatives of 14
industry and research groups working together to synthesise
published information, industry experience, and other expert
knowledge to reach a consensus about the future opportunities
and challenges for Pongamia in Australia. In some cases,
particularly for data pertaining to oil yield from seeds, much
higher and unsubstantiated estimates can be sourced from the
websites of some companies promoting Pongamia in Australia.
For the purpose of this paper, we take a conservative approach
and report figures that have been reported in peer-reviewed
literature, data collected in field trials conducted by the indus-
try, and research stakeholders contributing to this paper, or
where there was wide consensus among the group.
In summary, this review describes the opportunities for
Pongamia in Australia, a snapshot of what is already known,
the risks, uncertainties and challenges, and key priorities for
new research and development. This synthesis can be used
to underpin a well-founded and co-ordinated research strat-
egy to support industry development.
Pongamia and its Distribution
Pongamia (M. pinnata (L.) Panigraphi) [26] is a medium-
sized (10 to 15 m), leguminous tree; general features are
showninFig.1. Common names include Indian-beech,
ponga-oil-tree, Karanja tree, karum, and kanji, and the plant
has been synonymously known as Pongamia pinnata Merr.,
P. T. Scott :P. M. Gresshoff
ARC Centre of Excellence for Integrative Legume Research,
University of Queensland,
St Lucia,
Brisbane, QLD 4072, Australia
C. Stucley
Enecon Pty Ltd,
PO Box 175, Surrey Hills, VIC 3127, Australia
P. Wylie
Origin Energy,
GPO Box 148, Brisbane, QLD 4001, Australia
Bioenerg. Res.

Pongamia glabra Vent., Derris indica (Lam) Bennett, and
Millettia novo-guineensis [59]. The extent of Pongamia's
native range is uncertain due to a long history of cultivation
and transport, but the species is generally considered native
to the Indian sub-continent through central and south-east
Asia to northern Australia [17]. Pongamia is reported as
naturalised in China, Malaysia, Indonesia, Japan, Vietnam,
and the United States (Fig. 2).
In Australia, Pongamia occurs in the northern tropics and
subtropical east coast ranging from the coastal fringe around
Darwin through Cape York and as far south as northern NSW.
Records further inland are from locations along major rivers
including the Wenlock, Archer, and Holroyd Rivers in the Cape
York area, and the Norman River in the Gulf of Carpentaria.
The attractive architecture of Pongamia has seen it become a
common street tree in and around Brisbane and smaller towns
and cities along the east coast of Queensland.
A number of trial plantations have been established through-
out Queensland, in the Northern Territory, and in Western
Australia (Fig. 3). The largest commercial trial site (300 ha)
was established near Roma in central Queensland in 2010 on a
coal seam gas site; the longest running trial plantations were
established in Western Australia in 1999 by the Forest Products
Commission at the Frank Wise Institute in Kununurra and in
Queensland near Caboolture in 2007/8. Seeds for the Western
Australian collection were purportedly sourced from India but
details have been lost. Most Queensland seed material is de-
rived from trees growing on Brisbane streets which may have
been originally sourced from the Indian subcontinent.
The Opportunities
Regional Power Generation/Opportunities
A number of opportunities exist for regional power generation
either via biomass conversion to electricity or by running diesel
generators with Pongamia oil either as raw oil or after conver-
sion to biodiesel. For example, Ergon Energy runs and operates
33 diesel-fired generators that service remote communities in
Queensland and the Torres Strait (http://www.ergon.com.au/
community–and–our-network/network-management-and-
Fig. 1 Millettia pinnata:aabundant flowers in November/December
(southern hemisphere), pea-like flowers are clustered and pink to mauve;
bclustered seed pods in August/September (southern hemisphere) appear
on about 15–35% of flowers and are gray/brownish with either single or
double seeds; cmature seeds (1.6 g average); dseed storage cell showing
large protein bodies (P), oil vesicles (O), and starch grains (S) (photo-
graph courtesy of Prof. Ray Rose, Univ. of Newcastle); epinnate foliage,
leaves are waxy, dark-green, and arranged in 5 or 7 leaflet pinnate leaves;
fwell-nodulated root system showing determinate nodules (which in later
stages may develop branched structures); gmicroscopic section of a
Pongamia nodule showing infected central tissues, interstitial cells, and
vascular bundles in the periphery; hmultiple bud culture leading to clonal
regenerants (Q. Jiang, CILR, unpublished data); iearly stages of somatic
embryogenesis from Pongamia immature cotyledons (B. Biswas, CILR,
UQ, unpublished data); jDNA profiling of clonal Pongamia plants using
Pongamia-derived Interstitial Single Sequence Repeat (PISSR) amplifi-
cation and DNA silver staining ([7,28])
Bioenerg. Res.

projects/isolated-and-remote-power-stations). In large part,
these areas are also climatically suitable for Pongamia growth
[34]. A number of mining companies in northern Australia also
generate their own power using diesel generators that could be
fuelled by Pongamia oil.
Transport Fuels in Australia
About 41% of energy use in Australia is by the transport sector.
Most domestic passenger and freight trips are undertaken in
road vehicles, which account for 75% of transport fuel use. Air
Fig. 2 Distribution of Millettia
pinnata; not shown are several
records from the USA (Florida
and Hawaii) and central America.
Source: GBIF (accessed through
GBIF Data Portal, data.gbif.org,
2011-06-01) and records from
India extracted from [20,25,48,
56,57]
Fig. 3 A 28-month-old trial
plantation site near Caboolture,
southern Queensland
Bioenerg. Res.

transport is the second highest consumer (16%) followed by
water (4%) and rail transport (2%) [15]. The demand for
transport energy is growing at about 2.4% per year [15].
Forecasts by the International Energy Agency (IEA) and
many other energy forecasting organisations indicate a future
real oil price range of US$100 per barrel between 2015 and
2020, increasing to US$160 per barrel by 2050 [15]. Australian
petroleum net imports in 2009–10 were valued at A$14 billion
[1], and Australia's petroleum self sufficiency (2009–10) is
currently 59%. This is expected to decline to 24% by 2030
[1,2,23]. If oil production declines and oil prices increase as
expected, by 2029–2030, net oil imports could cost Australia
almost A$70 billion per annum in real terms [16].
The Future Fuels Forum [15] modelled Australia's future
fuel mix and projected that there will be a more diverse fuel
mix in road, rail, air, and sea passenger and freight travel.
Electricity, liquefied petroleum gas (LPG), natural gas, and
advanced biofuels are expected to increase in use once
production infrastructure has had sufficient time to scale
up [15]. The extent of their use will depend on primary fuel
prices and government greenhouse gas emission targets. The
CSIRO study [15] did not consider biodiesel or aviation fuel
from Pongamia due to the limited information on which to
make reliable projections.
Passenger vehicles powered by diesel engines are gaining
greater acceptance, and most heavy machinery as well as
marine and rail transport depends on high powered diesel
engines. In addition, mining companies are realising the ben-
efit of using bio-based diesel in their underground mines
because biodiesel fuels generally emit lower particulates in
comparison to fossil-based fuels [8], thus improving the health
and safety outcomes for air quality in underground mines.
Aviation
The aviation industry has recognised that bio-derived jet
fuels are an essential part of the industry's future greenhouse
gas emission reduction strategy. Biofuel blends have been
used in numerous test flights of commercial aeroplanes and
military jets, using oils from Camelina sativa,Jatropha spp,
algae, and oil palm. Pongamia oil has not been tested but
with increasing seed supply, chemical and engine testing is
being planned for the near future.
There are a number of ways that jet fuel can be produced
from bio-based oil or from lignocellulosic feedstocks. The
conversion pathway to convert plant-based oils using hydro-
deoxygenation is more efficient (65%) than for other path-
ways based on lignocellulosic feedstocks and can potentially
be conducted with some modification of modern oil refineries
[16]. Therefore, this pathway to jet fuel has a lower capital
intensity and is very attractive to the aviation industry [16].
However, due to the very low production of plant oils in
Australia, new non-food sources of oil would be required to
realise this pathway to jet fuel. Unlike the Future Fuels Forum
[15], the CSIRO Sustainable Aviation Fuel Road Map study
[16] did include the potential for Pongamia, but the informa-
tion used was extremely uncertain [21] and therefore the
estimates were very conservative. However, the study specif-
ically recommended that production of plant-based oils be
further assessed.
GHG Mitigation and Carbon Sequestration
Pongamia plantations and biodiesel production have the
potential to reduce GHG emissions by displacing fossil fuels
consumption and combustion. If Pongamia plantations are
established on previously cleared land, there may also be a
sequestration benefit through storage of carbon (C) in long-
lived tree biomass, possible increase in soil C stocks, and
use of husks and prunings to create biochar. In addition,
because Pongamia is a legume, there are likely to be lower
GHG emissions in comparison to non-legume oil production
because the need for nitrogen fertilisers may be reduced.
The opportunity may present under future policy develop-
ments (for example, the Carbon Farming Initiative Austra-
lian Government 2011 [5]) for the grower to be able to
access carbon payments for Pongamia plantations).
Realising the Opportunities
There are many overarching challenges to be addressed to
assess whether, how, where, and when the opportunities
outlined above could be realised. Pongamia is in the very
early stages of development as a commercial species. Invest-
ors in R&D and implementation, governments, industry
developers, and communities of interest will benefit from a
review of the knowledge base and gaps and a cohesive
national research strategy.
In the following sections, we outline ten key elements of
a comprehensive research strategy, briefly review the exist-
ing knowledge about those elements, and identify important
knowledge gaps and the actions needed to fill the gaps.
Element 1: Growth, Survival, and Reproduction
in Contrasting Biophysical Environments
Growth
Pongamia growth potential is being assessed in several field
trials in south-east Queensland, Western Australia, and the
Northern Territory. However, only a small number of plantings
have been designed to capture quantitative data on growth and
seed yield. Here, we report on some preliminary observations
from a few plantations in southern Queensland (Gatton in
Brisbane, Yandina, Eudlo and Caboolture on the Sunshine
Bioenerg. Res.

Coast and Hinterland, and Roma in south-central Queensland)
and from a plantation at Kununurra in the east Kimberley area
in northern Western Australia.
The University of Queensland, through the ARC Centre
of Excellence for Integrative Legume Research (CILR),
planted sapling material at the University of Queensland,
Gatton Campus in December 2008. The seeds were derived
from street trees under licence from Brisbane City Council.
Plantings were monitored for tree failure and replacement
seedlings were planted after 1 year. Growth results (Fig. 4)
indicate rapid biomass increases for both root and above-
ground tissues. Above-ground biomass increased to over
3 kg per tree (above-ground mass) after 2 years.
Rainfall
Experts agreed that average annual minimum rainfall between
500 and 800 mm was required for persistence of Pongamia,
with a further requirement for irrigation during the establish-
ment stage (discussed in more detail under “Element 7:
Agronomy”). Roots are generally fast growing and thick.
Within 2 years, plants appear to have reached deeper soil
layers and trees are able to tolerate periods of water deficit
without wilting. Established trees (6–10 years) survived
4 months without rain in Brisbane during the 2007–8drought.
Pongamia seed yield is severely affected by heavy rain
periods during the time of flowering. Heavy rain occurred in
south-east Queensland in November/December 2010, leading
to floods in Brisbane and surrounding districts. Extensive
flowering occurred in Brisbane, the Lockyer Valley and
Caboolture, but flowers collapsed either because of rain or
absence of insect pollination. Less than 5 % of flowers yielded
a seed-bearing pod. Pongamia develops flowers of different
maturity stages along each florescence, which may be an
adaptationto adverse conditions. However, prolonged adverse
conditions nullify this reproductive strategy. Plants severely
affected by spring rain are observed to re-flower in early
March (as the photoperiod matches that of the spring period).
It is unknown whether the late summer flowers will carry seed
which will mature in time for harvest.
Mature plants appear to survive moderate water-logging,
though some mortality occurs. Trees maintained in polybags
during the 2011 Brisbane floods survived inundation for
3 days at a depth of 3–4 m. The same was observed for sapling
trees in Yandina (southern Queensland) when the Maroochy
River flooded because of heavy rainfall and a king tide. Under
controlled glasshouse conditions at the Forest Products Com-
mission nursery in Perth, seedlings survive waterlogging in
fresh water; however, waterlogging in saline water (≥250 mM
NaCl) causes nearly complete mortality [4,51].
Temperature
Across the current Australian trial plantation sites, high tem-
peratures are common. For example, in Kununurra (north
Western Australia), average monthly maxima range from 30
to 39°C, and maximum temperatures can exceed 45°C [10].
Pongamia saplings and cuttings (60 cm in height) maintained
in a greenhouse, the temperature control unit of which failed
during the 2011 Brisbane flood, survived 65°C, though ample
water was available. While Pongamia appears to tolerate these
high temperatures, the impact of extreme heat combined with
drought on mature plants is unclear. In India, maximum tem-
peratures throughout Pongamia's distribution range from 27 to
38°C [41]. This agrees in general with Australian observa-
tions, though a distinction needs to be made between suitable
conditions for tree growth and production of oil, as opposed to
suitable conditions for persistence of natural stands. For ex-
ample, the plantation site near Roma in south-west Queens-
land appears to be suitable for Pongamia oil production under
irrigation (600 mm average rainfall, 2,200 mm evaporation),
although it is not within the range of climatic conditions that
naturalised populations of the species occur [34].
In Australia, Pongamia is cold- and possibly drought-
deciduous, undergoing a winter dormancy period. Night-time
temperatures appear critical in regulating Pongamia phenology.
Observations suggest that plants do not grow new leaves in
spring until minimum temperatures are consistently greater than
15°C, and that at least 6 months of minimum temperatures >
15°C are required for substantial foliage, flower, and seed
production.
Pongamia has been observed to survive and recover from
frost events. However, experts agreed that the species should
not generally be considered ‘frost tolerant’. At the Spring
Gully coal seam gas plantation site near Roma in Queensland,
a late frost occurred in September 2009 after the winter
dormancy period (i.e., trees had already put on new leaves).
Fig. 4 Above-ground biomass (g dry weight/tree±1 SD) of Pongamia
growing at Gatton, south-east Queensland. Plants are irrigated as
required and unfertilised. Soil is rich, volcanic loam (P. Scott, CILR,
unpublished data)
Bioenerg. Res.

Leaf blackening and abscission were observed after the frost
but trees were able to undergo profuse vegetative growth
again in October. Stem mortality occurred primarily in young
trees. About 20% of sapling material suffered from stem tip
die-back (10–30 cm), which did not appear to result in any
negative growth effect during the subsequent season. These
observations are generally consistent with reports from India
that indicate the tree can withstand ‘slight’frost [41,52].
However, experts noted that frosts have been observed to
result in sprouting from the base of saplings that suffer stem
mortality, which is undesirable from a production efficiency
perspective. Ideally, in a commercial setting, frost-damaged
saplings are replaced by retained nursery stock; replanting at
this early stage (year 1) does not appear to affect final planta-
tion uniformity.
Currently, very little is understood about the effect of
extreme weather, including drought, frost, flooding, cyclo-
nes, or extreme heat on Pongamia seed production and oil
yield. In addition, fire may pose a risk to Pongamia planta-
tions in some areas identified as potentially suitable; the
impact of fire on Pongamia has not been assessed.
Action: Field measures of growth and seed production
across climatic and soil fertility gradients should be used to
calibrate simple models (e.g., CLIMEX [67]) that could be used
to provide estimates of plantation performance in Australia.
Impacts of extreme events on Pongamia performance need to
be assessed.
Phenology and Reproduction
Plants are commonly observed to flower after 4–5 years
and usually only once per year. Some precocious flower-
ing has been observed by experts—for example approxi-
mately 6% of trees flowered and produced seed in the
second year in a trial planting at Gatton in southern
Queensland. A very small number of observations have
been made of two flowering episodes per year. Individual
flowers open for only a single day, though multiple stages
of maturity exist along the same florescence. Pongamia
requires tripping (i.e., forcing the pistil from its concealed
position within the petals of the flower) for pollination
to occur, and the main agents are bees [54]. Trials at
Kununurra indicated that the peak flowering period varied
between trees and that the presence of bee hives substan-
tially improved seed set and yield.
In general, and depending on location and winter dormancy,
Pongamia starts producing pods 4–7 years after planting with
full production from about 10 years of age. Some plants have
been observed producing seed pods after 2 years and data from
the trial plantation in Kununurra indicates only 37% of
9-year-old trees and 83% of 14-year-old trees set pods in any
1 year, suggesting considerable variability in these timeframes
[51].
The period for full development of the seeds can be as
long as 11 months in India [19] and Kununurra [4], and seed
pods are often still attached to the tree by the time of flower-
ing the following year. This may have consequences for
production as mechanical harvesting may damage these
delicate floral organs impacting on the subsequent year's
yield (see “Element 7: Agronomy”). Pods do not open
naturally, requiring mechanical opening/shattering or allow-
ing the fruit to decay before germinating. Mechanical decor-
ticators are used in India to release seed. The rate of
germination of seeds declines quickly (12 months for dry
storage; even less when on the ground where fungal attack
appears to destroy the seed).
Experts have all noted the high inter-tree variability in
phenology, growth, and reproduction and identify this as
one of the major impediments to commercial production.
For example, anecdotal observations suggest that trees
which have a high degree of genetic similarity, planted
adjacent to each other, may demonstrate vastly different
phenology and seed production. Pongamia has not under-
gone extensive domestication either in Australia or India, so
future development of commercial plantations will first re-
quire extensive genetic selection and/or improvement of
germplasm followed by clonal propagation to manage the
high inter-tree variability.
Action: Activities required regarding genetic selection
and clonal propagation are covered in more detail in
“Element 2: Strategy for Rapid Selection of Elite Genetic
Material”and “Element 4: Propagation and Establish-
ment”,respectively.
Soil–Climate–Growth–Yield Relationships
Recent studies to assess the national production potential
for a Pongamia industry in Australia used the simple
approach of matching the climatic ‘niche’of the plant
(based on data on current global distribution of Pongamia)
to where similar conditions exist in Australia, thus pre-
dicting the area potentially suitable for establishment of
the tree across Australia at a national scale [33,34]. Al-
though this provides a useful ‘first cut’on where the plant
might grow and survive under rain-fed conditions, it does
not provide useful information on the potential oil yield
from Pongamia. It is clear from the literature and from
observations by experts that there are complex relationships
between genetics, growing conditions, survival, and growth
of the tree, flowering, pollination and fruit set, and oil yield.
There is a considerable amount of anecdotal and observa-
tional information about Pongamia growth and productionfor
oil in India that could be used to develop climate–growth–oil
yield relationships which could then be applied across Austra-
lian climates to gain improved predictions of potential perfor-
mance. For example, the KarnatakaState Biofuel Development
Bioenerg. Res.

Boardstatesthatannualharvestsof600,000tofPongamiaseed
are collected by hand in village situations for biofuelproduction
[55]. Asinterest in Pongamia'spotential for biodiesel has grown
over the last few years, there has been a significant increase in
the published peer-reviewed literature with the mean annual
numberof published papers (containing ‘Pongamia pinnata’
or ‘Millettia pinnata’in the title, abstract or as a keyword)
increasing from five in the years up to 2005 (1991–2005)
to 26 in the 5 years since (2006–2010), peaking at 36
published papers in 2009. Approximately 75% of this
literature is generated in India; less than 2% (four papers)
originated in Australia. However, experts who have visited
with research and industry agencies in India note that much
knowledge has been generated which is currently inaccessible
via the peer-reviewed literature.
The experts generally agreed that, whilst valuable as a
background source of information, the published Indian
observations could not often be directly applied to the
Australian context for a number of reasons. Pongamia has
not traditionally been established in commercial plantations
in India. Rather, either natural stands have been harvested or
plants have been cultivated in small lots, on degraded land,
along roadsides and railways, and in open farmland and
there has to date been very little systematic collection and
processing of seeds [32]. As a result, little attempt has been
made to optimise production of the plant for harvesting,
identify elite genotypes, or investigate propagation method-
ology, although all these areas are seeing increasing atten-
tion in India. Kesari and Rangan [32] listed 28 research
organisations in India currently involved in “plus tree”iden-
tification, cultivation of Pongamia germplasm, and other
research relating to successful cultivation of Pongamia for
biofuel. Given the long history of usage, the potential
remains to collect vital, long-term data on seed production
and oil yield from across climatic gradients in India.
Action: Given the very limited local experience of the
performance of Pongamia in plantations, the challenge is to
make credible translation of overseas experiences to the
biophysical conditions of Australia. Meeting with key Indi-
an research groups and surveying plantations and natural
stands with a particular emphasis on understanding the basis
for variation in oil yields would assist to calibrate models for
Australia in the absence of local data and allow for an
interim improved prediction of oil production from Ponga-
mia plantations in Australia.
Element 2: Strategy for Rapid Selection of Elite Genetic
Material
Pongamia is an obligate outcrossing species; thus each tree
is highly heterozygous as confirmed by DNA fingerprinting
carried out at the CILR (UQ) using inter-simple sequence
repeats (ISSR) markers [27]. Variation is increased by the
heterogenous pollen stemming from other heterozygous ‘fa-
ther’trees. This has been confirmed visually and with mo-
lecular markers (ISSR), where all progeny plants derived
from one parent differed in DNA ‘fingerprint’[27]. As a
result, plants raised from seed are genetically diverse and
exhibit significant variation in many traits including tree
architecture, seed morphology, and yield [60]. Traditional
methods for development of ‘elite’trees, including cross-
breeding high performers, are only feasible if genetic lines
can then be maintained through clonal propagation (see
“Element 4: Propagation and Establishment”).
Pongamia is a diploid legume with 2n022. The chro-
mosomes are small at mitosis and resemble those of
soybean. An estimate of the genome size is around
600–700 megabase pairs per haploid genome. DNA and
RNA have been isolated and analysed from leaf and root
material. Modern high through-put DNA sequencing
techniques (specifically using Illumina SOLEXA technol-
ogy) have been applied and created large datafile sets of
Pongamia genomic sequence. These databases have been
used for gene discovery, especially using alignment with
the recently published soybean genome sequence [58].
For example, using this approach, genes for seed fatty
acid biosynthesis and stability and seed storage protein
have been isolated from Pongamia and characterised for
their developmental expression profile during seed matu-
ration (J. Vogt, P. Scott, and P. Gresshoff, CILR, UQ,
unpublished data). As an indirect measure of expression,
mRNA can be quantified for specific Pongamia genes,
different tissues, and growth conditions.
Proteins and oils can be isolated from seed cotyledons.
Oil extracted from seeds is found predominantly in the form
of triglycerides, with the major fatty acid being C18:1 (oleic
acid; a common component of olive and canola oil). Stearic
(C18:0) and palmitic (C16:0) acids, which contribute to a
rise in the cloud point are minor components, usually mea-
sured at between 9% and 17% of the total fatty acids [4,51,
59,61].
Action: The tools have been established to assist genetic
selection and need to be applied, and then selected material
needs to be evaluated by thorough and systematic field as-
sessment of growth and oil yield across potential Australian
growing environments.
Element 3: Exploiting Genotype × Environment
Interactions to Maximise Oil Yield
Very little is currently understood about the genotype×envi-
ronment interaction in Pongamia or the relationship between
environmental stress (induced by soil and climatic factors) and
oil yield in Pongamia. Seed production across and within trial
Bioenerg. Res.

sites and on street trees in Australia is highly variable. Table 1
summarises reproductive and yield variables based on
Australian observations to date. Seed production estimates
range from 0 to 30 kg seed/tree/year in an irrigated plantation
near Kununurra [51] to an estimated 80 kg seed/year on an
approximately 15-year-old tree growing on a street in
Brisbane. This high variability, particularly within trials, is
currently considered an area requiring considerable further
research and development. Accounts of seed yield from India
are highly variable but suggest an average range of 8–90 kg/
tree/year [31,57], although seed yields as high as 300 kg/tree
have been reported from specially selected high-yielding trees
[20]. It should be kept in mind that the Indian yield estimates
are sourced from trees identified as high-yielding, rather than
averages for trees in plantations; researchers in India note that
a large proportion of wild trees do not yield at all and that only
a small proportion of trees produce a ‘commercially attractive’
number of seeds [60]. Scott et al. [59]reportapotentialyield
in Australia of approximately 20,000 seeds from 10-year-old
trees/year. Based on their estimate of 1.8 g/seed, this converts
to a seed yield of 36 kg/tree or 12.6 t of seed per hectare based
on 350/trees/ha, provided all trees were productive.
Seed oil content has been measured from four trees within a
100-km radius in south east Queensland and found to be
within the range 35% to 43% (P. Gresshoff, CILR, unpub-
lished data); seeds from a trial plantation in Kununurra had an
oil content ranging from 31% to 45 % [4,51]. In India, total oil
content has been reported ranging from 15% to 50 %, with an
average for specially selected ‘candidate-plus’trees of 38%
(range 34% to 40%) [48] and averages from a random selec-
tion of wild trees being between 28% and 34% [32,41,66].
Little data is available for seed from other geographic areas,
but Arpiwi et al. [4] found Indonesian trees had 28% to 36%
oil. The oleic oil (C18:1) component appears relatively con-
sistent at an average of 50% of total oil content for trees from
south-eastQueensland (P. Gresshoff, CILR, unpublished data)
and an average 51% from trees in Kununurra [51], but
importantly, some trees had seeds which contained 63% oleic
acid [4].
While it is generally thought that larger seeds have higher
oil content, research in India suggests that oil content is only
very weakly, and not significantly, correlated with a range of
seed and pod morphometric traits including weight and size
of seeds and pods [48,66]. Preliminary data from a planta-
tion in Kununurra also indicates that seed size is not related
to oil content [4,51].
Action:Planting‘elite’clonally propagated genotypes
across environmental gradients in a systematically designed
network of long-term field trials is required, noting that effec-
tive cross-pollination of these trees will need to be managed to
optimise yield. Comprehensive long-term field studies, consis-
tently measured across the network of trial sites, will assist not
only with quantifying genotype×environment yield relation-
ships, but also with gathering agronomic and sustainability
datasets (see “Element 7: Agronomy”and “Element 9:
Sustainability”).
Element 4: Propagation and Establishment
With pollination of Pongamia occurring primarily via bees,
a pollen donor could include any tree within the distance a
bee is capable of carrying and transferring pollen (approxi-
mately 3 km radius). Therefore, once the best performing
genetic material is selected, trees must be clonally propa-
gated from stem cuttings or tissue culture, or via grafting to
maintain genetic lines. Significant effort is directed at clonal
propagation of elite (or ‘plus’) trees due to the need for
uniformity in plantations allowing equal usage of row space,
avoidance of shading and competition, uniform flowering
period, management and harvesting regimes and predictable
quality of products. Methods for cloning have been success-
fully demonstrated at the laboratory scale but require further
work to enable economic scale-up to support plantation
Table 1 Summary of reproductive and yield variables based on Australian observations to date
Variable Unit Range based on all
observations in Australia
Average Source
Time to reproductive maturity Years 4 to >14 years 5 years Expert observation and [51]
Full development of seeds Months 10–11 months 10 months Expert observation and [4]
Flowering episodes/year Number 1–2 1 Expert observation and [51]
Seed production per tree kg/year 0–30 kg/year 20 (a) Expert observation and [51]
Seed oil content % 31–55% 40 P. Gresshoff (unpublished data) and [4,51]
Seed viability Months <12 months Expert observation
Tree per hectare Number 320–500 350 (b) Expert observation
Yield estimate (if all trees are
productive)
Tonnes/ha/year 7 Calculated from (a) and (b)
Bioenerg. Res.

development. While it may be desirable to maintain uniform
genetic stock for commercial plantations, it is important to
be mindful of past problems (e.g., insect and plant patho-
gens) associated with extensive crop monocultures. It is
therefore considered that future plantings should incorporate
a variety of defined lines or cultivars of trees.
Experts agreed that whilst propagation from elite stock is
often promoted, there is very little information on how these
elite trees are identified or selected and virtually no data to
support the designation of trees as ‘elite’.Kesarietal.[31]
report a method for selection of “candidate plus trees”(CPT)
in India involving selecting individual trees possessing a range
of superior morphological and reproductive characters. Trees
in Kununurra, Western Australia, have also been selected
using several morphological and physiological traits [4].
However, the heritability of traits in offspring has not been
assessed or reported.
The current process for propagation of Pongamia in
Australia is labour-intensive, requiring manual extraction
of the seed, since commercial decorticators crack the seed
during removal from the pod. Seeds are first soaked in warm
water and then placed individually for planting to ensure the
seed is in the correct orientation for germination. Germina-
tion generally occurs within 2 weeks. Propagation from seed
is also the most commonly used method for production of
large numbers of seedlings in India [42]. Indian researchers
have reported a significant positive correlation between
germination rate and seed size [71].
Propagation from stem cuttings is a relatively simple pro-
cedure; however, it is labour intensive and requires source
material at the correct stage of development (i.e., semi-
woody). Pongamia twigs can be rooted to form clonal cuttings
which establish in soil and develop a deep fibrous root system
over time (but slower than tap root development on seedlings).
This tendency to develop a fibrous, adventitious root system
in cuttings is considered less than optimal, particularly in
moisture-deficient soil systems. Classical grafting of elite
germplasm onto seedling derived root stock has also been
demonstrated (P. Gresshoff, CILR, UQ, unpubl. data).
Propagation via tissue culture can take alternative
approaches. For example, dormant buds can be sterilised then
cultured to induce multiple buds which can be separated and
grown to full scale plants (Q. Jiang, CILR, unpublished data).
Sterilisation of dormant buds is difficult to achieve from field
grown material, but easier from clonal glasshouse material.
This procedure is both labour and infrastructure-intensive and
requires optimisation for commercial application to reduce
costs. Immature cotyledons have been induced to undergo
both organogenesis as well as early stages of somatic embryo-
genesis (B. Biswas, CILR, unpublished data). Optimally, or-
ganogenesis or somatic embryogenesis should be obtained
from meristem-derived material assuring clonal propagation
of superior germplasm. In India, increasing attention is also
being focussed on propagation techniques via tissue culture
and a comprehensive review of the current state of the re-
search is given in Mukta and Sreevalli [42].
Propagation via grafting has been conducted with some
success in India and is being trialled in some Australian
plantations in 2011. In India, wedge grafting has been found
to be most successful using 3-month-old seedlings raised in
polybags as the stock and semi-hardwood scions of 12–18 cm
length from high-yielding trees [42]. The advantage of prop-
agation via grafting, besides the potential for higher produc-
tivity due to elite scions, is the earlier time to seed production.
Indian trials have shown seed yield within 3 years following
grafting [42].
Action: While propagation from tissue culture and micro-
propagation of Pongamia has proven successful, the meth-
ods require much further refinement to be feasible and cost-
effective on a commercial scale.
Element 5: Identification of Suitable Land and Water
Resources
Soil and Water
In Australia, Pongamia has been observed growing on a wide
range of soil types. Trial plantations have been established on
sodic acid soils, alkaline soils, and heavy clay soils with a sodic
subsoil. Plants have also been observed growing on beach sand
near Darwin and on sand levies along rivers in Cape York. In
India, Pongamia is also reported to grow on a wide range of soil
types from stony to sandy to clay [32], though it is noted that
the plant does not do well on dry sands. Trees reportedly grow
in coastal, saline habitats [12], but Indian field trials on saline
soils have yielded mixed results [68,70]. Despite tolerance to a
wide range of soil types, soil conditions are likely to interact
strongly with climate to markedly affect rates of Pongamia
growth, but this is currently poorly quantified.
Water requirements for satisfactory rates of seed and oil
production by Pongamia are poorly understood, but experts
suggested that irrigation is required during the establishment
phase of the plantings (first 7 years) in dry tropical and
subtropical areas and sometimes subsequently in order to
ensure seed set. There are examples of plantings where trees
have been successfully established without irrigation. A
plantation on the Sunshine Coast hinterland of Queensland
was established without irrigation, even surviving the
drought period of 2007–2008. These trees have grown to
nearly 3 m in height and 10 cm stem diameter within 4 years
(this growth is less than the irrigated trial plantation at
Gatton in southern Queensland, where plants achieved these
measures of growth within 2 years).
Land and water use or allocation issues may arise with
Pongamia plantations if they are to be established on a large
Bioenerg. Res.

scale. Kriticos et al. [34] identified zones of productivity for
growth, based on rain-fed situations. Areas requiring no
irrigation only occur in the very northern and coastal areas
of Australia. There may be other competing demands for
this land including biodiversity and conservation, high value
agriculture, or urban land use. However, relatively small
high yielding plantations may be well suited to providing
oil for remote communities. There are some irrigated lands
in crop and grazing zones that could be used for Pongamia;
however, the feasibility of this would be driven at least in
part by the economics of, and societal attitude towards,
using irrigation water for a dedicated energy crop.
Water availability in northern Australia is highly seasonal
and may be limited in many areas. Therefore, if irrigation is
required, it may require the use of groundwater. It has been
estimated that there is approximately 600 GL year
−1
of
potentially useable groundwater in northern Australia and
that this could provide irrigation for 40,000–60,000 ha [36].
There are specific opportunities for irrigation, for example,
in association with mining ventures, but these have yet to be
systematically investigated and quantified.
Action: A systematic approach to identifying land (within
suitable rainfall zones, or with access to irrigation) capable
of supporting commercial Pongamia production should be
conducted.
Salt Tolerance
Pongamia is promoted as being able to produce oilseeds on
low productivity, degraded or salt-affected land thereby
lessening competition for higher productivity land used for
agricultural production [32,46]. However, pot and field
trials of growth and performance in saline conditions have
provided mixed results [63,69,70] and in controlled glass-
house trials in Perth, seedlings were not tolerant of water-
logging and salinity levels of 250 mM NaCl [4].
Pongamia could have the benefit of soil rehabilitation
through nitrogen fixation; however, recent experiments car-
ried out on Australian seedlings and saplings shows a decrease
in nitrogen concentration and total nitrogen of nodulated
plants at moderate to high salinity levels (i.e., approximately
10–20 dSm
−1
)[74]. The reduction in nodulation with increas-
ing salinity in Pongamia is comparable with that shown by
Acacia ampliceps, another salt-tolerant legume that has been
widely used for the purpose of reclaiming salt-affected land in
Australia [74]. A. ampliceps has improved nodulation and
nitrogen fixation in saline environments when inoculated with
salt-tolerant strains of rhizobia [74]. The long-term impacts of
salinity on mature trees are not understood.
Action: Efforts are required to ascertain whether N-fixation
is the primary or only limitation to growing Pongamia in a
commercially successful manner on degraded or salt-affected
land. Further investigation on the effect of inoculation of
Pongamia with salt-tolerant rhizobia is required if this is
considered to be a major limitation to production in these
landscapes.
Element 6: Development of New Production Systems
and Value Chains
New Production Systems
There is potential to develop and establish new types of
production systems for Pongamia, as well as the value
chains—for example for conversion of oil to aviation fuel.
New production systems might combine Pongamia planta-
tions, grazing, and carbon farming which could provide
enterprise diversification, reduction of risk, and reduced
GHG emissions for the grower. High value co-products
may also be a component of an innovative new mixed
enterprise model (explored further below).
Action: Little is known about the scale and type of oppor-
tunities for Pongamia to begrown in a complementary fashion
with other land uses such as grazing or mining and quantifying
the location and scale of such opportunities would help to
focus efforts in industry development. This is usually an
iterative process which starts with pre-experimental or ex-
ante modelling analysis on the performance and economics
to assess what may be feasible. Promising production systems
can then be trialled and evaluated, with progressive refinement
over time to fine-tune new systems.
Animal Feed Co-products
The seed of Pongamia consists of an outer hull portion (~6%
mass) and an inner kernel portion (~94%). Following oil
extraction, approximately two thirds by weight of the original
seed is left as a residual meal or cake, containing 28–34%
crude protein [73]. The Pongamia meal or cake(also known as
karajin cake) has been used as manure, fungicide, and insec-
ticide, and there has been considerable research, mainly in
India, on utilisation of this protein meal as animal feed [35,47,
49,73]. However, the meal contains karanjin (a fluro-
flavinoid) and pongamol in the residual oil that make it
unpalatable. It also contains anti-nutritional factors such as
phytates, tannins, and protease inhibitors that affect rumen
metabolites and the digestibility of protein and carbohydrates
[73]. Oil extraction carried out by the usual method of expeller
pressing, leaves 15–20% oil in the cake (referred to as EKC—
expeller pressed karajin cake). Solvent extraction removes
more oil and should increase the palatability of the meal and
reduce the toxicity, but research indicates that inclusion of
solvent extract Pongamia meal (SKC—solvent extracted kar-
ajin cake) in mixed diets still reduces feed intake and results in
reduced animal growth rates. Researchers have sought
Bioenerg. Res.

additional ways of detoxifying the meal aimed at reducing the
anti-nutritional factors through water leaching and the addi-
tion of mild acid or alkali. In a laboratory study, Vinay and
Kanya [73] use a 2% HCL treatment for 1 h to reduce anti-
nutritional factors.
A long-term (34 weeks) performance trial of lambs was
undertaken using diets containing either 24 % expeller
(EKC) or 20% solvent extracted (SKC) Pongamia meal,
replacing half of the de-oiled groundnut cake as the source
of protein [64]. In this trial, there were no further treatment
of the meal to reduce anti-nutritional factors. Dry matter
intake, the digestibility of protein and carbohydrates, the
growth rate and wool production were all reduced in the
lambs subject to each of the diets containing either EKC or
SKC. In addition, by the end of the trial, the lambs had
lower bone density (osteoporosis), testicular degeneration,
and liver and spleen lesions. Growth performance trials with
chickens also demonstrate that Pongamia meal may only be
useful as animal feed at very low levels of addition [47].
Despite the research that has been undertaken over many
years to find ways of utilizing Pongamia meal as livestock
feed, the combination of poor palatability, anti-nutritional
factors, and the recognition through molecular analysis that
the primary proteins in the meal are known to provide low
nutritional benefit because of poor amino acid composition,
make it unlikely that a co-product stream based on animal feed
will be developed. However, there is a benefit from Pongamia
containingthe unpalatable karanjin and pongamol, as it allows
the integration of grazing livestock in Pongamia plantations
with minimal risk of the animals grazing and damaging the
trees. At a trial plot in southern Queensland, where the trees
are 3–4 years old, sheep are grazed in the plantation to control
grass and weed growth and to provide some additional income
from the land (G. Muirhead pers comms.).
Green Manure Co-products
Pongamia is used as a green manure with some benefits [43],
but this is derived from the leaves of the tree rather than the
oilseed cake. However, trials have shown that oilseed cake can
be used in conjunction with the mycorrhiza Glomus fascicua-
tum in organically enrichedsoils to reduce the incidence of the
plant disease complex caused by the root knot nematode,
Meloidogyne incognita and the root wilt fungus Fusarium
udum in pulse crops viz. cowpea, soybean, pigeonpea [24].
Insecticide Co-products
In terms of use as an insecticide, extracts of Pongamia have
been reported to be effective against insect pests in stored
grains and on crops, acting as a deterrent to oviposition and
as antifeedants and larvicides against a wide range of pests
[35]. The relevance of this to the use of Pongamia oilseed
cake is questionable, as it appears that the oil (as a water–oil
suspension of up to 2%) has generally been used as a spray
to achieve the desired insect inhibiting effect [49].
The pod shells and woody material from pruning could
potentially be used as a form of fertiliser, produce biochar,
combusted to produce electricity, or be used as a feedstock
for gasification and conversion to a range of products. This
requires further investigation.
Action: Avenues for sustainable use or disposal of co-
products, including the seed cake, pods, and woody material
from pruning, need further investigation.
Element 7: Agronomy
Irrigation
Irrigation has been discussed under “Element 5: Identification
of Suitable Land and Water Resources”and is not discussed
further here.
Nitrogen Fixation and Fertiliser Management
Relatively little is known regarding nodulation and actual
rates of N fixation in Pongamia. Preliminary experiments
suggest that Pongamia is able to form functional spherical
nodules with a broad range of rhizobia belonging to the
Bradyrhizobium tribe [59]. Such bacteria commonly nodu-
late Australian acacia (wattle) species. Their persistence in
Australian soils may present a hurdle to establishing highly
effective Bradyrhizobium strains for Pongamia that will
persist in field situations, as competition from the ‘local’
rhizobia may be severe. The nodule structure (see Fig. 1f)
suggests determinate nodule growth similar to that observed
in soybean [22] and the model legume Lotus japonicus [27].
However, observations on field-grown Pongamia roots
show nodules ranging from spherical (as seen in saplings,
[3]) to branched and coralloid nodules (P. Gresshoff and P.
Scott, CILR, unpublished data).
Pongamia plants are thought to exhibit the classical le-
gume nodulation response called autoregulation of nodula-
tion (AON; [14,22]). Nodulation occurs predominantly in
the upper regions of the root system as early nodulation
events suppress the formation of new nodules. Thus, sapling
inoculation with effective bacteria may give the plant suffi-
cient nodule numbers for early plant development, without
incurring problems of ‘competition’from resident rhizobia.
Application of fertiliser at the seedling stage probably
enhances establishment success and early growth but expert
observations at some trials (with fertile soils) suggest it may
not be necessary. However, addition of P, K, and micro-
nutrients may be required over the long term to maintain soil
fertility. Experts note that soil and foliar analysis is required
Bioenerg. Res.

at plantation sites to provide a basis for establishing appro-
priate fertiliser regimes.
Action: Characterisation of the spectrum of rhizobia that
can form an effective symbiotic relationship(s) with Ponga-
mia is required. An assessment of whether nitrogen fixation
capability at plantation densities is likely to meet the plants'
nitrogen requirements needs to be undertaken.
Weed Control
Mechanical and chemical weed control during the first 3 years
after planting was identified by the experts as critical for suc-
cessful establishment. In particular, seedlings <30 cm high are
very vulnerable to weed overgrowth. Ideally, weed mat would
be used for establishment; however, the cost is significant
(approximately $1.40 per tree). Indian and Australian observa-
tions suggest planting of seedlings of 50–60 cm in height will
greatly improve survival in the field [72]. Intercropping with
suitable species during the period of establishment (i.e., first 3–
4 years) may also contribute to management of weeds, as well
as increase economic returns for the system.
Animals are required to be fenced out for the first 3 years
of Pongamia growth because they will pull seedlings out of
the ground; after that, stock will only feed on the lower
branches if other feed is scarce. The minor ‘pruning’carried
out by stock is likely to be beneficial in controlling root or
base sprouting.
Action: Knowledge about effective weed control, fertiliser
management, spacing and pruning from Indian plantations in
needed to provide some early information to help guide the
management of Australian plantations. Systematic evaluation
of agronomic practices needs to be conducted under a range of
prospective Australian growing environments and manage-
ment systems.
Harvesting Methods
Mechanical harvesting of Brisbane city trees has been demon-
strated with umbrella shakers style machinery [9]. Umbrella
shaker style harvesters require a minimum of 7 m spacing
between rows. The large trial plantation near Roma has been
planted with 8 m spacing between rows and 2.5 m between
trees within the row. Another trial plantation at Caboolture
utilises a 5/7/5/7 m spacing pattern between rows with 5 m
spacing within the row. The optimal arrangement for accom-
modating a gantry style shaker with maximum trees per hectare
is thought to be 7 m spacing between rows and 4 m between
trees within the row, which gives approximately 320 trees/ha.
Another consideration for optimisation of harvesting is tree
shape. Pongamia can tend towards a ‘poplar’or ‘weeping
willow’shape which cannot be harvested efficiently. Therefore,
some pruning of trees is required during the establishment
phase (first 3 years) of the plantation to control tree shape.
Further pruning is required to adjust for wind effects. Plants are
generally pruned following harvest with the aim of maintaining
trees at a height of approximately 6 m. The presence of shoots
that will develop flowers or flower buds at the time of harvest/
pruning needs to be considered. Future genetic selections may
focus on semi-dwarf varieties with high yield.
Action: Harvesting methods for plantation scale plantings of
Pongamia require considerable further development and test-
ing. Options for further investigation include gantry and um-
brella style shakers similar to those used for harvesting in nut
and olive plantations. These harvesters have been trialled suc-
cessfully at a small scale on Pongamia in Australia; however,
trial plantations are currently harvested predominantly by hand.
The possibility of using abscission chemicals to release mature
pods prior to flower development should also be investigated.
Pests and Diseases
In north Queensland, Pongamia has been observed to be
infected by a fungus (Phyllachora yapensis subsp ponga-
miae) causing a disease known as ‘tar spot’[62]. The fungus
has also been recorded in India and is known as Phyllachora
pongamiae [11]. The fungus causes a leaf discolouration but
does not appear to cause mortality or seriously impact
mature trees; however, it may have more serious impacts
on seedlings. Also recorded on native Pongamia in north
Queensland is the fungus Asperisporium pongamiae which
causes leaf spot [62]. Other fungi causing leaf spot and
blight recorded on Pongamia in India include Fuscicladium
pongamiae,Microstroma pongamiae,Cercrospora ponga-
miae [39], and Ravenelia hobsoni (leaf rust) [11].
A number of other potential pests of Pongamia have been
observed in trials around Australia (a stem borer, leaf miner,
locusts, green ants), but none appear to cause significant
damage. The only pest observed to cause mortality in seed-
lings has been rabbits (ring-barking the lower 20 cm of the
stem), and as noted earlier, grazing animals need to be
fenced out of Pongamia plantings for the first 3 years.
Kangaroo damage has not been observed in plantations in
mixed grass-wooded areas, suggesting that macropods
avoid the plant, possibly because of a bitter taste.
Action: While there is little evidence that pests and dis-
eases currently cause anything other than minor foliage
damage to Pongamia in Australia, establishment of Ponga-
mia as a broad-acre crop will provide increasing opportunity
for pest and pathogens to establish and the consequences of
this need careful assessment.
Element 8: Economics
The price of biodiesel is inextricably linked to the price of
crude oil because it is the main competitor, although the cost
Bioenerg. Res.

of production may be more independent (depending on the
level of oil-derived inputs for growing, processing, and
transporting the product). In many countries, biodiesel is
used primarily as a fuel additive. Commonly, blends range
from 2% to 20%. A comparison of the economics of various
alternative transportation fuels requires estimation of their
total costs of production, from the cost of raw materials for
fuel production to the cost of conversion to biodiesel and
distribution. Successful development and commercialisation
of biodiesel or other fuels of products from oils of farm
grown crops depends on (a) their cost competitiveness com-
pared with that of the product they replace (e.g., conven-
tional diesel) and on the amount of fuel that could be
supplied annually and (b) on the competitiveness of oil
crops compared with alternative land uses. Social and envi-
ronmental policies may provide incentives that can assist in
the development of emerging renewable fuels industries.
A comparison of the commercial viability of production
of biodiesel requires estimation of its costs of production,
from the cost of oil crops grown on farms, the costs of
transport and processing, and the costs of distributing the
fuel to users. A full economic analysis for selected produc-
tion systems is currently being conducted by the Future
Farm Industries Cooperative Research Centre for produc-
tion, harvest and delivery of Pongamia oil including the cost
of crushing and refining oil to biodiesel [65]. The analysis
takes into account the fixed and variable costs of production
of biodiesel from Pongamia oil including:
&Initial capital outlays
–Establishment and conversion of land to a Pongamia
tree plantation
–Development of irrigation systems (if required)
–The building and commissioning of crushing plant and
its machinery
–Machinery for harvest and transport of seed
&Fixed costs
–General repair and maintenance
–Sundry fuel and oil
–Electricity
–Administration
–Permanent staff wages
–Manager wages
&Land opportunity cost from livestock on pasture
–The value of net revenues foregone if farm land is
converted to a plantation reducing the stocking rate or
carrying capacity of pasture
&Variable costs
–Machinery operating costs including fuel and oil and
additional hired labour
–Fertiliser, including mulch
–Weed, pest, and disease control—costs of chemicals and
their application
–Irrigation water—if required and where there is a charge
for water or if it has an opportunity cost
–Labour for pruning
–Harvest
–Crushing
The economic analysis requires numerous inputs ranging
from growth and yield of trees to the cost of extracting oil
from crushing of seeds. Given the lack of an established
commercial Pongamia industry, it is not possible to source
precise and verifiable estimates of the input parameters for
such a model. The lack of reliable data on oil yield (tonnes per
hectare per year) over the life of the tree is particularly critical.
However, for many of the cost items, it is possible to find
estimates from other related agricultural and horticultural
industries.
A preliminary analysis was conducted of the cost of estab-
lishment and operation of a 500-ha rain-fed Pongamia plan-
tation in sub-tropical coastal Queensland with a rainfall of
1,030 mm per annum (e.g., Rosedale 24.63° S, 151.92° E).
The findings of that preliminary analysis are reported here for
the purpose of identifying the key economic drivers and to
inform priorities for research and development. An exhaustive
discussion of the details of all the assumptions and input
parameters used in this model is beyond the scope of this
paper (but see [65]). It must be emphasised that these are
preliminary findings and are subject to change and modifica-
tion as more reliable information becomes available. The
results of this type of preliminary economic analysis, when
viewed from the point of view of paucity of data, may be
valuable in highlighting the uncertainties about Pongamia that
are likely to be economically important and drive its ultimate
commercial success and scale of adoption.
The key assumption that was varied in the model was
seed yield. Two scenarios were tested for the purpose of
illustration in this paper. Both scenarios are based on plant-
ing 500 trees per hectare allowing suitable space to manoeu-
vre a Collossus harvester (a commercially available machine
used in large olive and orange orchards internationally, or
similar). In scenario A, each tree was assumed to yield an
average of 40 kg of pods per year (range 35–50 kg/year)
when trees are mature at around 10 years, equating to
approximately 20 kg/seed/tree/year. This figure represents
the average seed production estimated by industry experts
and researchers who contributed to this paper. The growth of
the tree and production of seeds follows a sigmoidal curve
as shown in Fig. 5(for scenario A). In scenario B, a lower
estimate of pod yield of 10 kg per tree (equating to 5 kg/
seed/tree) was used to represent a situation where trees are
less productive and is a far more conservative production
Bioenerg. Res.

scenario. Ideally, genetic improvement (as discussed in
“Element 2: Strategy for Rapid Selection of Elite Genetic
Material”and “Element 3: Exploiting Genotype× Environ-
ment Interactions to Maximise Oil Yield”) would improve
on the upper average yield estimated here of 40 kg/tree; thus
even our upper estimate may ultimately be considered
conservative.
In this case study, an annual harvest regime is assumed.
Industry experts who are actively involved in developing
commercial Pongamia plantations expect that it may be
possible to harvest in the month or two before flowering
(around November) given adequate winter rainfall. This is
an area that requires verification with field trials. If winter
rainfall is necessary those areas of Australia with highly
seasonal rainfall, for example the northern tropics, may not
be suitable for growing Pongamia unless supplemented with
irrigation in winter. This scenario is not assessed here;
however, the model does have provision for inclusion of
irrigation infrastructure and costing of capital expenses as
well as the variable cost of water charges.
The nutritional requirements of the crop are assumed to be
met by a combination of fertilising and mulching with by-
products such as seed meal and pod and seed shells returned
from the crusher back to the property. Pruned branches and
twigs clipped by the harvester are also returned to the planta-
tion to avoid loss of nutrients. The fertiliser costs are assumed
to be associated with the use of fertiliser containing nitrogen,
phosphate, potassium, and the trace elements exported from
the plantation. The fertiliser costs are assumed to ramp up in
step with the growth and harvest of trees starting at ~$30 per
hectare in the first year when plants are small and increasing to
$340 per hectare when trees are mature and being harvested.
We stress that these costs are highly uncertain and have a
major effect on the economics of production of Pongamia oil.
Harvesting haulage and delivery costs are assumed to be
$127 per tonne of seeds in pods or about 5 cents per litre of
oil. Harvesting operation is assumed to depend on the pur-
chase and use of the Colossus harvester. This type of har-
vester and associated gear including bins and trailers is
valued at $900,000. Harvesting manually would make the
venture unviable by increasing the cost by around tenfold
which is in keeping with reported estimates from the olive,
macadamia, and almond industries.
Crushing costs are a combination of operating and capital
expenses. The crushing plant with a crushing capacity of
12.5 t of seed per 10-h day is assumed to cost around $0.5
million to build. This plant's operating costs are assumed to
be $223,912 per annum. Crushing costs amount to less than
a third of a cent per litre of oil extruded but it goes up to
around 1.5 cent per litre in scenario B in which trees seed
yields are only 10 kg/tree per annum.
Land opportunity cost is the net operating surplus in dollars
per hectare from grazing that a land holder in that region
would forego as a consequence of switching their land use
to Pongamia. We assume that some grazing and hay produc-
tion is possible from the grass and other herbage growing
around and under the Pongamia trees in the plantation. How-
ever, the competition for light, water, and nutrients from trees
is assumed to halve the production of pasture. It is the net loss
of grazing potential of the land that is used as the opportunity
cost. Here, we assume the long-term average return reported
for high rainfall sheep grazing enterprises in similar regions.
Pollination services offered by bees supplied by apiarists are
assumed to be negligible in cost based on the assumption of
mutual benefit between the two enterprises.
Carbon payments are estimated for a hypothetical scenar-
io where a Pongamia plantation may qualify as an activity
for removal of carbon from the atmosphere. This analysis
0
10
20
30
40
50
60
70
80
90
100
0
50
100
150
200
250
300
0 5 10 15 20 25 30 35 40
Product yield (kg/tree)
Green biomass and carbon (kg/tree)
Tree Age (Years)
Oil Meal Shells Biomass Carbon stock
Growth and sequestration - Lines on the left hand vertical axis:Products - Bars on the right hand vertical axis:
Fig. 5 Pongamia growth (lines,
left hand axis) and product
yield (bars, right hand axis)
estimates used in the economic
model for scenario A with yield
at an average of 40 kg pods/
tree/year
Bioenerg. Res.

considers the possibility that the modelled plantation may
satisfy the rules of the Carbon Farming Initiative (CFI)
legislation of the Australian Government [18]. Carbon pay-
ments are estimated according to an endpoint averaging
system. This is because carbon stored in agricultural soils
and some forms of vegetation are likely to be susceptible to
significant cyclical variations, largely driven by fluctuations
in annual average rainfall. These variations can make it
difficult to isolate the impact of changes in management
practices on carbon stocks. For this reason, estimation meth-
ods for sequestration projects must provide for estimates to
be adjusted to account for significant variations in carbon
stocks that are likely to occur as a result of climatic cycles.
The project must be undertaken in accordance with a spec-
ified and approved methodology and comply with scheme
eligibility requirements. Another key criterion is that the
project must be beyond common practice in the relevant
industry or part of an industry or in the environment in
which the project is to be carried out. Under the CFI legis-
lation, carbon payments may be based on total projected net
greenhouse gas removals over the period of scheme obliga-
tions less a risk of reversal buffer. If the Pongamia plantation
qualifies as a positive carbon sequestration activity and is
included on the positive list of CFI, then growers may get
credit for voluntary participation in the CFI scheme. The
carbon price is assumed to start at $23/t of CO2-e and rises
by 2.5% per annum. Carbon revenue is estimated to be
$3,346/ha over 40 years or around 2 cents per litre of oil
in scenario A. In scenario B, carbon revenues are the same
per hectare at $3,346/ha, matching the growth of tree bio-
mass which generates the same amount of sequestered car-
bon as that in scenario A. However, carbon revenue is
higher per litre in scenario B at just over 8 cents per litre
since seed yield of each tree is assumed to be four times
lower when compared to scenario A. It should be noted that
eligibility of Pongamia plantations in relation to CFI legis-
lation and the attendant future carbon revenues are highly
uncertain; thus, in Table 2, results are reported with and
without carbon revenues.
The preliminary results reported in Table 2are based on
the net present value (NPV) of cashflows. NPV is calculated
over the 40 year life of the hypothetical Pongamia project.
We use the NPV to provide a dollar per hectare estimate of
the cost of production from a Pongamia plantation in present
value terms. These results indicate how sensitive the cost of
production of oil is to key factors of production. In scenario
Table 2 Cost of production of Pongamia oil for two different yield scenarios over a 40-year life cycle
Cost category Scenario A Scenario B
Land Oil Land Oil
$/ha over 40 years Cents/l $/ha over 40 years Cents/l
Capital (excludes value of land)
Establishment of site, planting of trees, crushing plant, machinery 9,384 6.00 9,384 24.00
Opportunity cost
Foregone net ruturns from alternative land use (e.g., grazing) 656 0.42 656 1.68
Variable costs
Machinery—tractor, implements (fuel, oil, parts, repair and maintenance) 1,128 0.72 1,128 2.88
Fertiliser and mulch 3,975 2.54 3,685 9.42
Control and management of weeds, pests, and diseases 2,237 1.43 2,237 5.72
Prunning labour 2,487 1.59 2,487 6.36
Harvesting 7,977 5.10 6,182 15.81
Crushing seeds for extraction of oil 448 0.29 593 1.52
Fixed costs
General repair and maintenance 267 0.17 267 0.68
Power, fuel, and oil 347 0.22 347 0.89
Administration and wages of manager and staff 6,786 4.34 6,786 17.35
Total costs 35,691 22.82 33,751 86.31
Carbon revenue 3,246 2.07 3,246 8.30
Total costs less carbon 32,445 20.74 30,506 78.01
Equivalent annual value—total costs ($/ha/year) 2,677 2,532
Both scenarios are based on a 500-ha plantation with 500 trees/ha. Scenario A assumes 40 kg pods/tree/year when trees are 10 years old; scenario B
assumes 10 kg pods/tree/year when trees are 10 years old. Also shown (final row) is the annualised NPV which provides a dollar per hectare per
annum estimate of the cost of production in today's dollars (using a discount rate of 7%). For full details of assumptions and input parameters used
in this model, see [65]
Bioenerg. Res.

A, with an annual yield of 40 kg of pods per tree, cost of
production is $35,691 per hectare (before carbon credit)
over 40 years. This translates to the cost of production of a
litre of Pongamia oil of around 23 cents per litre. On the
other hand, scenario B, with a yield of 10 kg of pods per tree
per annum has a higher cost of production of oil at 86 cents
per litre and $33,751 per hectare (before carbon credits) over
40 years.
The estimates of costs are included and discussed
here in order to indicate a plausible range of values
which must be scrutinised and modified over time as
the industry develops and future research and develop-
ment generates the better data. The data in Table 2is
indicative of the important cost items. Oil yield/ha is a
critical variable determining the overall economics of
the Pongamia plantation project.
Action: Further certainty is required around many of
the parameters influencing the establishment and produc-
tion costs of Pongamia and many of these have been
identified in previous elements including phenological
and reproduction parameters (“Element 1: Growth, Survival,
and Reproduction in Contrasting Biophysical Environ-
ments”), propagation and establishment methods (“Element
4: Propagation and Establishment”), production systems and
value chains (“Element 6: Development of New Produc-
tion Systems and Value Chains”) and agronomic parame-
ters (“Element 7: Agronomy”). The economic model
provided here will require updating and further sensitivity
analysis as new and more precise information becomes
available.
Investment Risk and the Pongamia Industry
From an investor's perspective, the risk associated with an
Australian Pongamia industry are currently high, but the pros-
pects for reducing risk in the future through a comprehensive
research program are good (Fig. 6). High uncertainty is pri-
marily due to the fact that there are large uncertainties about
the ability to supply Pongamia oil at competitive cost. These
are driven mostly by a lack of knowledge about suitable and
available land and water requirements for Pongamia produc-
tion in Australia, as well as uncertainties with respect to yield
and oil content of the seed in the Australian environment.
Nevertheless, research aimed at determining the potential land
area available for Pongamia, and genetic and technological
developments to improve consistency of yield and seed oil
content will substantially reduce the future risks associated
with supply. Other risks related to the legal environment,
technology for oil extraction, and social acceptability of the
product are relatively small and are expected to be minor in
the future due to Australia's stability and governance, well-
known technologies and a highly skilled labour force, as well
as the enhanced perception of the need to reduce GHG emis-
sions, and the proposed development of an Australian bioen-
ergy sustainability standard (see “Element 9: Sustainability”).
The other risk components associated with the size of the
Australian demand for biodiesel and International oil prices
are currently high but will likely reduce over time. Forecasted
oil prices are higher in the future, improving the competitive-
ness of biodiesel and increasing demand. Figure 7summarises
how the biological and environmental factors identified
erutuFksiRyadoTksiR
Risk to investor
International oil prices
Australia biodiesel demand
Technology
Social acceptability
Legislation
Area planted
Oil yield
Fig. 6 Schematic indicating
current and future risk to
investors of an Australian-based
Pongamia industry
Bioenerg. Res.

throughout our review interact with the other external forces to
determine market potential and risks associated with a com-
mercial Pongamia production system in Australia.
Element 9: Sustainability
Sustainability issues arise at each stage of the value chain, as
well as across the whole value chain and must be addressed
at different scales and within different social and environ-
mental contexts. Sustainability issues arising directly from
the bioenergy value chain are reasonably well-defined and
understood [45]. However, the drivers to expand renewable
energy (GHG mitigation, fuel security and regional devel-
opment) could lead to a rapid expansion of the bioenergy
industry, with many associated implications for sustainabil-
ity. Because Pongamia is not a food crop, diversion of food
is not an issue per se, but diversion of arable land or water
resources may become one if Pongamia plantations begin to
scale-up dramatically.
There are multiple dimensions to achieving ‘sustainabil-
ity’. Sustainable production requires the maintenance of
critical ecosystem function for long term delivery of the full
range of values (including the market values of agriculture
or energy crops, and the non market values such as ecosys-
tem services) from the land. For Pongamia, important
dimensions may include assessment of the potential for
invasiveness and effects on biodiversity as well as an ability
to play a role in mitigating GHG emissions and in restoring
salt-affected lands. However, land and water resources will
be increasingly contested and pressured for production of
food, fibre, water, biodiversity, carbon storage, and urbani-
sation. Pongamia and a new biofuel industry could also have
benefits for developing regions by opening new market
opportunities for biofuel feedstock crops and increasing
incomes of farmers. The impacts of an expanded Pongamia
industry on the above aspects may be positive or negative.
They need to be fully assessed and reported. These issues
are discussed in detail in O'Connell et al. [45].
Action: Further investigation is required around the envi-
ronmental benefits and risks of large-scale Pongamia pro-
duction—for example potential impacts on land, water and
biodiversity resources, and the social acceptance and poten-
tial socio-economic benefits at regional to national scales of
a new biofuel crop. It is important to have a solid under-
standing of the likely GHG balance of plantation establish-
ment and management, and the bioenergy production phases
of the industry. Both the potential GHG emissions and the
potential for carbon storage in biomass, as well as the
savings from substitution of fossil fuels by biofuels, require
assessment of each aspect per se, as well as an integrated
evaluation of the tradeoffs between them.
Demonstration of Sustainability Credentials
Sustainability is a critical issue for the biofuel industry
internationally as well as in Australia. Many governments
and market segments now consider that quantitative, robust,
and independently verified (or certified) sustainability cre-
dentials are vital in order for the bioenergy industry to
expand globally [45]. This type of approach is already
translating to government policies in many countries,
Can Pongamia
be established?
Where can
Pongamia be
grown?
What are t he
risks?
What is the
market
potential?
How much
can be
produced?
G x E, Land
suitability and
resources , New
production sy stems
and value chains
Land suitability
and resources,
Genetic
selection,
Agronomy,
Econom ics
Climat e
growth/surv ival/
reproduct ion,
Genetic selection,
Propagation,
Sustainability
Potential
distribution
Yiel d
Biological an d
Environ mental factors
Socio -econ omic
factors
Biodiesel
Co-products
Te c h n o l o g y
Legislation
Acceptability
Substitute
fuels
External Systems
Inte rnati ona l Oil
prices
Inte rna tional
biofuel price
Fig. 7 Interaction of biological
and environmental factors and
socio-economic factors which
determine the market potential
and risk for commercial Ponga-
mia production in Australia.
The left-hand side box indicates
the contribution of the integrat-
ed research strategy to the two
key questions which influence
market potential, i.e., potential
distribution and yield. The
right-hand side box outlines
those variables that are also in-
fluenced by external forces, i.e.,
international oil and biofuel
prices
Bioenerg. Res.

including Australia. These policies will limit market access
and government support to only those biofuels which meet
specified sustainability criteria. The recent Australian legis-
lation to extend the period for excise relief for biofuels
requires that in order to qualify, the biofuels must meet
ISO sustainability standards. An ISO process for developing
sustainability standards for production, supply chain and
application of bioenergy is currently in progress (TC248
2011).
Action: The Pongamia industry would benefit from par-
ticipating in the ISO and any interim process. This will
require assisting with adaptation of international criteria
and indicators, making the requisite field and other measure-
ments, and making this information available to third parties
conducting audits and verification in order to obtain
certification.
Many aspects of sustainability have been discussed under
Elements 1–8; the issue of biosecurity has not been raised
under other elements and is briefly discussed here.
Invasiveness
Large-scale planting of woody species for biofuels in Aus-
tralia will require further consideration of the potential for
weedy growth and invasion of natural or other agricultural
areas. Recently, Biosecurity Queensland produced a Weed
Risk Assessment (WRA) for Pongamia. The WRA deter-
mined that Pongamia poses a low risk to Queensland based
primarily on the fact that there is currently no evidence that
Pongamia has significant negative impacts as a weed else-
where in the world and that it is considered naturalised in
Queensland [17]. However, in a review on potential weed
issues with biofuel crops in Australia, Low and Booth [37]
of the Invasive Species Council suggested that “Because
this plant has a demonstrated capacity to spread from culti-
vation, it should not be grown outside its natural range close
to national parks or watercourses. It should be declared a
restricted plant that should not be grown near sensitive
areas.”These publications highlight concern by government
and non-government agencies in Australia about Pongamia's
potential for invasion. In Hawaii, where Pongamia has natu-
ralised, it is considered to be ‘high risk’for invasion based
on the Australian/New Zealand Weed Risk Assessment cri-
teria, adapted for Hawaii [13,50]. This high risk score is
generated because the species is considered to have natural-
ised widely and be tolerant of a wide range of soil and
climatic conditions, as well as exhibiting other character-
istics typical of invasive weeds such as production of a large
number of viable seeds and extensive suckering [50].
Several characteristics of the species establishment and
survival observed in Australian trials point to low potential
for invasiveness under most circumstances; (1) the majority of
seeds only remain viable, even when stored with care, for 12
to 18 months, (2) seeds remaining in the pod where they fall
are vulnerable to fungal infection which experts have ob-
served to prevent seed germination, (3) seeds and seedlings
planted in cultivated or uncultivated ground without subse-
quent weed control have very low survivorship, (4) very little
recruitment from street planted trees in Brisbane, likely orig-
inally sourced from Indian stock, has been observed over the
last century.
A low score on a weed risk assessment in Queensland does
not negate the need for further consideration of management
and ecology aimed at limiting the potential for invasiveness and
does not guarantee that Biosecurity agencies will not impose
further regulation on its cultivation, particularly if new evi-
dence arises. In particular, the introduction of germplasm from
more vigorous individuals and elite stock from India or else-
where into large-scale plantations significantly increases the
risk of invasiveness [17,37]. The WRA also highlights the risk
involved with the importation of Pongamia germplasm that
introduce new genetic material into the Australian Pongamia
population, possibly enhancing its fecundity, adaptability, and
invasion potential. The assessment recommends that genetic
material sources from existing Australian naturalised stocks
should be used.
Action: Best-practice standards for minimising both the
risk of invasion and the introduction of exotic genetic ma-
terial to the Australian Pongamia population need to be
identified and implemented.
Element 10: Integration and Knowledge Management
Australia has an opportunity to deliver the much needed out-
puts from a comprehensive research program (including
maps, spatial and temporal data on resources, technologies,
economics, sustainability indicators, GHG emissions) in a
synthesised, modern and effective manner. Potential benefi-
ciaries include sectors of government (policy makers and
analysts at Australian, state and local levels), industry peak
bodies (e.g., Bioenergy Australia), industry (energy pro-
ducers, recycling corporations, biomass collectors), research-
ers (scientists working on bioenergy, land-use, sustainability,
regional development), and the public.
Action: In order to gain a social license to operate, the
bioenergy industry will benefit from engaging the broader
community with a set of clear messages to explain the different
technologies, the opportunities for regions and industries, and
the sustainability credentials. These messages, if they are to
gain the confidence of the community, need to be demonstrably
underpinned by robust science. If the plan as presented here is
implemented, there will be a great deal of new knowledge
generated and an even greater need to apply state of the art
knowledge interpretation and synthesis, management, and
delivery.
Bioenerg. Res.

A Comprehensive Research Strategy
Our review has identified several key areas for future research
and development to support the expansion of a Pongamia
industry in Australia. Here, we summarise our review and
outline a comprehensive research strategy to fill the gaps in
knowledge about the potential for Pongamia to be utilised as a
biofuel crop in Australia.
Figure 8synthesises the ten key knowledge gaps and
research questions identified by our review and highlights in
brief the actions required to address the knowledge gaps. The
strategy starts with an element that relates to survival, growth,
and reproduction in Australian climates and edaphic condi-
tions. Key to addressing the knowledge gaps in this area is the
need to establish a structured network of long-term field trials
across climate, soil, and fertility gradients that run long
enough to capture year to year variability in climate. Trial
plantations established with a sound experimental design are a
vital component of the comprehensive research strategy and
can be used for collection of data to address many of the
knowledge gaps identified in this paper. In addition, the
experts agreed that there is still a lot that could be learned
from the long history of use of Pongamia for fuel in India and
that there is a large amount of research on commercial
Fig. 8 A summary of the ten
key research priorities and
actions
Bioenerg. Res.

production of Pongamia currently being undertaken in India
which is difficult to access. An assessment of this research
may allow for modification of the scope and methodology of
any field trials and further research undertaken in Australia.
The second element involves developing and implement-
ing a strategy for rapid selection of elite genetic material for
Pongamia. The ability to select and improve genetic mate-
rial is considered vital by industry stakeholders for the
progression of a Pongamia industry.
The third element combines outputs from the first ele-
ments to understand the genotype×environment relationship
particularly as it relates to oil yield. This element can only
be understood through investment in trial plantations where
growth and yield in varying environments can be assessed
over the long-term.
The fourth element covers methods for propagation and
establishment of Pongamia on a commercial scale. In fact,
an inability to successfully propagate clonal material at a
commercial scale may be a ‘deal-breaker’for the viability of
the industry.
The fifth element (linked to the first and third elements)
involves understanding land suitability across Australia
through a systematic analysis. This element also addresses
assessing the suitability of land for nitrogen fixation and the
ability to grow Pongamia in degraded and salt-affected or
salt-irrigated land.
Element 6 deals with identification of opportunities for new
production and farming systems and new value chains. Pro-
duction of Pongamia provides the opportunity to establish
novel types of farming systems which integrate production
systems taking into account crops, grazing, carbon farming,
and renewable energy. This could have many benefits at the
‘grower’part of the value chain including enterprise diversi-
fication, reduction of risk, and reducing GHG emissions.
The seventh element identifies the uncertainties related to
agronomy for commercial Pongamia production. These
uncertainties can also be addressed partly by data collected
from field trials in conjunction with specific experimental
methods (e.g., silviculture, pest control) and be further sup-
plemented by modelling approaches.
The economics of Pongamia production, harvest, deliv-
ery of Pongamia oil, and refining to biodiesel are covered in
the eighth element. A preliminary economic analysis of
production costs for Pongamia in Australia is already un-
derway, and the results of this will help identify where
further research in understanding the economic viability of
a commercial Pongamia production system in needed.
The ninth element identifies questions of sustainability.
Robust and independently verified (or certified) sustainabil-
ity credentials are vital in order for the Pongamia industry to
expand in Australia.
The tenth and final element involves integrating, synthe-
sising, managing, and delivering the outputs from this
comprehensive research strategy to achieve a clear set of
messages with the goal of achieving broad community
acceptance
Conclusions
This paper puts forward the combined knowledge, data, and
expertise of most of the active research and industry groups
working with Pongamia in Australia. It highlights the exist-
ing knowledge, the critical knowledge gaps, and suggests a
cohesive strategy for national R&D within a risk manage-
ment framework.
Pongamia shows potential for increasing Australia's cur-
rent low level of plant oil production, using a non-food crop.
The tree is leguminous and does have the potential for high
oil yields (perhaps 2–8 t/ha/year). However, there are many
challenges to address which could be solved by investing in
a significant and structured R&D program. Other chal-
lenges, for example, availability of suitable land and water
resources which are increasingly contested, or the continued
volatility of oil prices, alsoneedtobeconsideredand
planned for.
We conclude that there is sufficient evidence about the
potential for Pongamia to warrant investment in well struc-
tured R&D over the next decade. This R&D would link
molecular level genetic research through to paddock scale
agronomic research, landscape scale investigation of new
production systems and value chains, and system scale
research into a range of aspects of sustainability. Addressing
the challenges and knowledge gaps as described in this
paper may enable the promise of Pongamia as a significant
new source of plant based oils in Australia (and potentially
many other places in the world) to be realised.
Acknowledgements This work has been funded by the CSIRO En-
ergy Transformed Flagship, the University of Queensland Strategic
Fund and the affiliated organisations of all authors. We thank our
colleagues Dr. Trevor Booth, Dr. Jim Smitham, and Dr. Mick Poole
and two anonymous reviewers for their valuable comments.
References
1. ABARE-BRS (2010) Australian Mineral Statistics: June Quarter
2010: Australian Bureau of Agriculture and Resource Economics—
Bureau of Rural Sciences, Canberra.
2. ABARE (2010) Australian Energy Statistics: Australian energy
consumption by industry and fuel type. Australian Bureau of
Agricultural and Resource Economics www.abare.gov.au
3. Arpiwi NL, Watkin ELJ, Yan G et al (2011b) Phenotypic and
genotypic diversity of the root nodule bacteria nodulating Millettia
pinnata, a biodiesel tree. 17th Nitrogen Fixation Congress Fre-
mantle WA, 27 Nov–2 Dec 2011.
4. Arpiwi NL, Yan G, Barbour EL et al (2012a) Genetic diver-
sity, seed traits and salinity tolerance of Millettia pinnata (L.)
Bioenerg. Res.

Panigraphi (syn. Pongamia pinnata), a biodiesel tree. In
review.
5. Australian Government (2011) Carbon Farming Initiative. Depart-
ment of Climate Change and Energy Efficiency http://www.clima
techange.gov.au/cfi cited 8th July 2011.
6. Axelsson L, Franzen M (2010) Performance of Jatropha biodiesel
production and its environmental and socio-economic impacts.
Dissertation, Techical Report. FRT 2010:06. Chalmers University
of Technology: Sweden.
7. Bassam BJ, Gresshoff PM (2007) Silver staining DNA in poly-
acrylamide gels. Nat Protoc 2:2649–2654
8. Beer T, Grant T, Campbell PK (2007) The greenhouse and air
quality emissions of biodiesel blends in Australia: Report for
Caltex Australia Limited, Report Number KS54C/1/F229 (ed.
Commonwealth Scientific and Industrial Research Organisation
(CSIRO) Australia, Aspendale, Victoria.
9. BioEnergy Plantations (2011) http://wwwbioenergyresearchco
mau/home/ cited 11th July 2011.
10. BOM. (2011) Bureau of Meterology. Australian Government.
[http://bom.gov.au] cited 15th August 2011.
11. Borah RK, Dutta D, Hazarika P (1998) Some new records of fungi
from North East India. Bano Biggyan Potrika 27:41–13
12. Bringi NV, Mukerjee SK (1987) Karanja seed (Pongamia glabra)
oil. In: Bringi NV (ed) Non traditional oilseeds and oils of India.
Oxford IBH Publishing, New Delhi, pp 143–166
13. Buddenhagen CE, Chimera C, Clifford P (2009) Assessing biofuel
crop invasiveness: a case study. PLoS One 4:e5261
14. Caetano-Anolles G, Gresshoff PM (1991) Plant genetic control of
nodulation. Annu Rev Microbiol 45:345–382
15. CSIRO (2008) Future Fuels Forum—Fuel for thought: Common-
wealth Scientific and Industrial Research Organisation (CSIRO)
Australia, http://www.csiro.au/resources/FuelForThoughtReport.
html, Canberra.
16. CSIRO (2011) Towards establishing a sustainable aviation fuels
industry in Australia and New Zealand—Sustainable aviation fuel
road map: Commonwealth Scientific and Industrial Research Or-
ganisation (CSIRO) Australia, Canberra.
17. Csurhes S, Hankamer C (2010) Weed Risk Assessment: Pongamia:
The State of Queensland, Department of Empolyment, Economic
Development and Innovation.
18. DCCEE (2011) Carbon Credits (Carbon Farming Initiative) Bill
2011. Explanantory Memeorandum. Circulated to the Senate—The
Parliament of the Commonwealth of Australia by the Minister for
Climate Change and Energy Efficiency.
19. Dhillon RS, Hooda MS, Ahlawat KS et al (2009) Floral biology
and breeding behaviour in karanj (Pongamia pinnata L. Pierre).
Indian For 135:618–628
20. Divakara BN, Alur AS, Tripati S (2010) Genetic variability and
relationship of pod and seed traits in Pongamia pinnata (L.)
Pierre., a potential agroforestry tree. Int J Plant Prod 4:129–141
21. Farine DR, O'Connell DA, Raison JR et al (2012) An assessment of
biomass for bioelectricity and biofuel, and for greenhouse gas emis-
sion reduction in Australia. Glob Change Biol Bioen 4:148–175
22. Ferguson BJ, Indrasumunar A, Hayashi S et al (2010) Molecular
analysis of legume nodule development and autoregulation. J Int
Plant Biol 52:61–76
23. Geoscience Australia and ABARE (2010) Australian Energy Re-
source Assessment: Geoscience Australia and Australian Bureau
of Agricultural and Resource Economics Canberra
24. Goswami BK, Pandey RK, Goswami J et al (2007) Management of
disease complex caused by root knot nematode and root wilt
fungus on pigeonpea through soil organically enriched with Vesic-
ular Arbuscular Mycorrhiza, karanj (Pongamia pinnata) oilseed
cake and farmyard manure. J Environ Sci Health Part B: Pestic
Food Contam Agric Wastes 42:899–904
25. Hooda MS, Dhillon RS, Dhanda S et al (2009) Genetic divergence
studies in plus trees of Pongamia pinnata (Karanj). Indian For
135:1069–1080
26. IPNI (2011) The International Plant Names Index. http://www.ipni.
org/index.html [Accessed 12 August 2011].
27. Jiang QY, Gresshoff PM (1997) Classical and molecular genetics
of the model legume Lotus japonicus. Mol Plant Microbe Interact
10:59–68
28. Jiang QY, Gresshoff PM (in prep) DNA markers and diagnos-
tics of the tree legume Pongamia pinnata using PISSR (Pon-
gamia Inter-Simple Sequence Repeat) primers.
29. Kant P, Wu S (2011) The extraordinary collapse of Jatropha as a
global biofuel. Environ Sci Technol 45:7114–7115
30. Kazakoff SH, Gresshof PM, Scott PT (2010) Pongamia pinnata,a
sustainable feedstock for biodiesel production: Energy Crops: RSC
Energy and Environment Series No 3 (ed. by NG Halford & A
Karp) Royal Society of Chemistry
31. Kesari V, Krishnamachari A, Rangan L (2008) Systematic charac-
terisation and seed oil analysis in candidate plus trees of biodiesel
plant, Pongamia pinnata. Ann Appl Biol 152:397–404
32. Kesari V, Rangan L (2010) Development of Pongamia pinnata as
an alternative biofuel crop—current status and scope of plantations
in India. J Crop Sci Biotech 13:127–137
33. Kriticos D (2012) Regional climate-matching to estimate current
and future sources of biosecurity threats. Biol Invasions.
doi:10.1007/s10530-011-0033-8
34. Kriticos DJ, Murphy HT, Jovanovic T et al (in prep) Estimating
current and future climate suitability patterns for a bioenergy crop:
growth and weed potential.
35. Kumar M, Singh R (2002) Potential of Pongamia glabra vent as
an insecticide of plant origin. Biological Agriculture & Horticul-
ture 20:29–50
36. Land and Water Taskforce (2009) Northern Australia Land and
Water Science Review: report Coordinated by the Common-
wealth Scientific and Industrial Research Organisation (CSIRO)
Australia, Canberra.
37. Low T, Booth C (2008) The weedy truth about biofuels: Invasive
Speices Council, Melbourne.
38. Meher LC, Dharmagadda VSS, Naik SN (2006) Optimization of
alkali-catalyzed transesterification of Pongamia pinnata oil for
production of biodiesel. Bioresour Technol 97:1392–1397
39. Mohan V (2012) Pathological problems of economically important
forest tree species in India—an overview. Division of Forest Pro-
tection, Institute of Forest Genetics and Tree Breeding, Coimba-
tore. http://agritech.tnau.ac.in/forestry/forest_disease_index.html.
Accessed 11 Jul 2011
40. Mukta N, Murthy IYLN, Sripal P (2009) Variability assessment in
Pongamia pinnata (L.) Pierre germplasm for biodiesel traits. Indus
Crops Prod 29:536–540
41. Mukta N, Sreevali Y (2009) Investigations on an uncommon acces-
sion of Pongamia pinnata (L.) Pierre. Indian For 135:293–295
42. Mukta N, Sreevalli Y (2010) Propagation techniques, evaluation
and improvement of the biodiesel plant, Pongamia pinnata (L.)
Pierre—a review. Indus Crops Prod 31:1–12
43. Muthukumar T, Udaiyan K (2002) Growth and yield of cowpea as
influenced by changes in arbuscular mycorrhiza in response to
organic manuring. Journal of Agronomy and Crop Science
188:123–132
44. O'Connell D, Batten D, O'Connor M et al (2007) Biofuels in
Australia—issues and prospects. Rural Industries Research and
Development Corporation, Canberra, Australia
45. O'Connell D, Braid A, Raison J et al (2009) Sustainable
Bioenergy Production: a review of global bioenergy sustainabil-
ity frameworks and assessment systems. RIRDC Publication No
09/167.
Bioenerg. Res.

46. Odeh I, Tan D, Ancev T (2011) Potential suitability and viability of
selected biodiesel crops in Australian marginal agricultural lands
under current and future climates. BioEnergy Res 4:165–179
47. Panda AK, Kumar AA, Singh SD et al (2008) Growth performance
and pathological lesions in broiler chickens fed raw or processed
karanj (Pongamia glabra) cake as protein supplement. Indian J
Anim Sci 78:997–1001
48. Pandey AK, Nivedika G, Pankaj B et al (2010) Evaluation of
Pongamia pinnata (L.) Pierre. progenies for their growth perfor-
mance in Madhya Pradesh, India. World App Sci J 10:225–233
49. Pavela R, Herda G (2007) Effect of pongam oil on adults of the
greenhouse whitefly trialeurodes vaporariorum (Homoptera: Tria-
leurodidae). Entomologia Generalis 30:193–201
50. PIER (2009) Weed risk assessment—Pongamia pinnata. Pacific
Island Ecosystems at Risk WRA, Hawaiian Ecosystems at Risk
(Department of Forestry, USDA) http://www.hear.org/pier/wra/pa
cific/pongamia_pinnata_htmlwra.htm
51. Plummer J, Arpiwi NL, Yan G (2010) Millettia pinnata (Ponga-
mia) a biodiesel tree from the tropics. Presentation at the Bioen-
ergy Australia conference, Sydney, 8-10th December 2010.
52. Prasad R, Pandey RK (1987) Vegetation damage by frost in natural
forests of Madhya Pradesh. J Trop For 3:273–278
53. Prinsley R (2009) The National Bioenergy Research Development
and Extension Strategy. Presentation at the Bioenergy Australia
Conference, Gold Coast, 8–10 December 2009.
54. Raju AJS, Rao SP (2006) Explosive pollen release and pollination as
a function of nectar-feeding activity of certain bees in the biodiesel
plant, Pongamia pinnata (L.) Pierre (Fabaceae). Curr Sci 90:960–967
55. Ramakrishna YB (2011) Exploration of Pongamia pinnata as the
next biodiesel crop. Presentation at the Biowise Conference, Kuala
Lumpur, March 2011.
56. Ramesh N (2008) Studies on provensance, nursery mixture and pre
sowing treatments on quality and characterisation of Pongamia,
Vol. Masters: University of Agricultural Sciences, Dharwad.
57. Rao G, Shanker A, Srinivas I et al (2011) Diversity and variability
in seed characters and growth of Pongamia pinnata (L.) Pierre
accessions. Trees Struct Func: 1–10.
58. Schmutz J, Cannon SB, Schlueter J et al (2010) Genome sequence
of the palaeopolyploid soybean. Nature 463:178–183
59. Scott PT, Pregelj L, Chen N et al (2008) Pongamia pinnata:an
untapped resource for the biofuels industry of the future. BioEn-
ergy Res 1:2–11
60. Sharma S, Negi M, Sinha P et al (2011) Assessment of genetic
diversity of biodiesel species Pongamia pinnata accessions using
AFLP and three endonuclease-AFLP. Plant Mol Biol Rep 29:12–
18
61. Sharma YC, Bhaskar S, Korstad J (2010) High yield and conver-
sion of biodiesel from a nonedible feedstock (Pongamia pinnata).
J Agric Food Chem 58:242–247
62. Shivas RG, Alcorn JL (1996) A checklist of plant pathogenic and
other microfungi in the rainforests of the wet tropics of northern
Queensland. Aust Plant Path 25:158–173
63. Singh K, Yadav JSP (1999) Effect of soil salinity and sodicity on
seedling growth and mineral composition of Pongamia pinnata.
Indian For 125:618–622
64. Singh P, Sastry VRB, Garg AK et al (2006) Effect of long term
feeding of expeller pressed and solvent extracted karanj (Pongamia
pinnata) seed cake on the performance of lambs. Anim Feed Sci
Technol 126:157–167
65. Stucley C, Schuck SM, Sims REH et al (in prep) Biomass Energy
Production in Australia. Revised Edition. Rural Industries Re-
search and Development Corporation, Canberra.
66. Sunil N, Kumar V, Sivaraj N et al (2009) Variability and diver-
gence in Pongamia pinnata (L.) Pierre germplasm—a candidate
tree for biodiesel. Glob Change Biol Bioen 1:382–391
67. Sutherst RW, Maywald GF, Yonow T et al (1999) CLIMEX.
Predicting the effects of climate on plants and animals. User
Guide. CSIRO Publishing, Melbourne, Australia
68. Tomar O, Gupta R (1985) Performance of some forest tree species
in saline soils under shallow and saline water-table conditions.
Plant Soil 87:329–335
69. Tomar OS, Gupta RK (1985) Performance of some forest tree
species in saline soils under shallow and saline water-table con-
ditions. Plant Soil 87:329–335
70. Tomar OS, Minhas PS, Sharma V et al (2003) Performance of 31
tree species and soil conditions in a plantation established with
saline irrigation. For Ecol Manage 177:333–346
71. Ukey JK, Koshta LD, Bajpai R et al (2008) Genetic parameters for
seed traits in Pongamia pinnata. Indian J Trop Biodiv 15:164–166
72. Venkatesh A, Vanangamudi M, Vanangamudi K (2003) Effect of
seedling grade on growth and survival of pungam (Pongamia
pinnata). J Trop For Sci 15:231–233
73. Vinay BJ, Kanya TCS (2008) Effect of detoxification on the
functional and nutritional quality of proteins of karanja seed meal.
Food Chem 106:77–84
74. Wilkinson CS, Fuskhah E, Indrasumunar A et al (2012) Growth,
nodulation and nitrogen gain of Pongamia pinnata and Glycine
max in response to salinity. BioEnergy Research, in review.
Bioenerg. Res.