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Genetic survey of Pinus radiata. 2: Population comparisons for growth rate, disease resistance, and morphology
... Eventually, a transition from producing green apical tufts to brown sealed buds is completed (Figures 4 and 5). In P. radiata, maturation progresses more gradually than in most pines [32,34], although the rate of progression varies both among populations and among individual genotypes [58][59][60]. As maturation proceeds, the seasonal alternations in phenological state become more pronounced, with shoot elongation peaking earlier in the season [8,23]. ...
... This has profound implications for interpreting the radial profile of fibre properties within the annual ring according to position on the bole. In P. radiata, maturation progresses more gradually than in most pines [32,34], although the rate of progression varies both among populations and among individual genotypes [58][59][60]. As maturation proceeds, the seasonal alternations in phenological state become more pronounced, with shoot elongation peaking earlier in the season [8,23]. ...
... Pinus radiata shows a strong radial progression from corewood to outerwood (socalled juvenile wood and mature wood) [58]. Density initially progresses rapidly out from the pith, approaching a roughly asymptotic value from around the 15th ring, placing the species in Type 1 of Schimleck et al. [73]. ...
Seasonal phenology is expressed in the annual rhythms of growth and quiescence, which may range from being sharply defined to weakly quantitative. These rhythms, both vegetative and reproductive, are a key aspect of a plant’s survival strategy. They enable the plant to both survive seasonal stresses and take advantage of favourable conditions, while making pollination efficient through synchronised flowering. Maturation in woody perennials causes some ontogenetic modulation of seasonal phenology. Shoot phenology is driven by various environmental cues, notably temperatures and daylength, with shoot extremities often being prime receptors. The phenology of shoot extremities is in turn seen as a strong driver of cambial activity, which itself is an aspect of shoot phenology and the basis of stem diameter growth. The aspects of cambial activity reflecting hoot–tip phenology primarily involve the timing of xylem formation and the anatomical and physical properties of xylem cells. The actual amount of diameter growth, however, is governed much more by other factors, notably the growth potential of the species, the space for the tree to grow in, and how favourable local conditions are for growth. Somehow, all tree species allocate resources to shoot extension and diameter growth to represent viable adaptive strategies, although there is no identified role of phenology per se in such allocation. Among species, Pinus radiata is extremely important commercially, largely through a high growth potential that reflects distinctive phenology. Much research on the species provides a basis for linking its phenology and shoot–tip architecture to seasonal timing of diameter growth and fine details of within-ring variation in xylem cell properties. This provides a baseline for comparison with many other tree species, conifers and hardwoods. Selected examples are considered to illustrate the range of adaptive strategies. Regulation of diameter growth and internal variation in wood properties reflects the response to competitive pressures. Modifying the regulation to optimise wood production and quality poses a great challenge for future domestication.
... For two of the individual lots (Table 5), Kaingaroa and Southland, the conesponding proportions were two-thirds to threequarters, depending on the assumption concerning the stafus of seedlots 3 and 4. For Nelson the corresponding proportion was slightly under onehalf. The little if any local differentiation within Monterey and Cambria accords with results of the smaller-scale monoterpene study of Burdon, Gaskin, Zabkiewicz and Low (1992) and results for a variety of field traits (Burdon, Bannister and Low 1992;Burdon et at. 7997 ;Falkenhagen 1991 ;Ades and Simpson 1991) g.nrìit contamination from alien P-radiata, introgression of genes from nearby P. attenuata, and founder effects (genetic drift) due to past recolonisation from scattered trees. ...
... -^-*Feei'-"'*ôe ËålËlË Discussion While expressing monoterpene levels as percentages of a mixture is not ideai, the data þoperties made it virrually imperative' Moreover, it is only an assumption, however plausible, that canonicai distances are linearly related .to the percentages of genes coming from progenitors' ilo*.u.r, the agteement with evidence for other traits(Burdon, Bannister and Low 1992;Burdon, Gaskin, Zabkiewicz and Low 1992; ...
... Some uncertainty over the ancestry of the NZ seedlots stems from results for theAño Nuevo lots, but that does not affect the main conclusions. Our results corroborate those ofBurdon, Bannister and Low (1992),Burdon, Zabkiewicz and Andrew (1992), andBurdon et al. (1997) in: no indication of any genes from Cambria, the closer resemblance of the NZ material overall to Año Nuevo than to Monterey, and the closer resemblance to Año Nuevo of Kaingaroa materi al than Nelson material despite independent land-race samples. The closer resemblance of Nelson to Monterey could have arisen from the initial local representation ofthe native population, or through Monterey enjoying a unlikely on circumstantial grounds, and is not suiported by the evidence for various other traits(Burdon, Bannister and Low 1992; Burdon et al. ...
... The good performance of Aiio Nuevo at high altitudes in the southern South Island is reassuring in view of its predominance in the ancestry of local stock, and argues against recruiting much Monterey material for breeding for such sites. Given the relatively quick maturation (physiological ageing) of Afio Nuevo (Burdon et al., 1992a), this endorses the still uninvestigated suggestion that cuttings with some maturation may have better snow resistance than seedlings. It also suggests that hybrids of Guadalupe trees may have good snow resistance, given both the rapid maturation of Guadalupe seedlings (Burdon et al., 1992a) and the altitude and climate of the island (Libby et al., 1968); in fact some hybrids have been planted experimentally on high-altitude, snow-hazard sites in New Zealand. ...
... Given the relatively quick maturation (physiological ageing) of Afio Nuevo (Burdon et al., 1992a), this endorses the still uninvestigated suggestion that cuttings with some maturation may have better snow resistance than seedlings. It also suggests that hybrids of Guadalupe trees may have good snow resistance, given both the rapid maturation of Guadalupe seedlings (Burdon et al., 1992a) and the altitude and climate of the island (Libby et al., 1968); in fact some hybrids have been planted experimentally on high-altitude, snow-hazard sites in New Zealand. ...
... The provenance trials compared mostly growth rates, form, wood properties, and resistance to diseases for commercial plantations. Variation in resistance to pathogens and pests varies within all populations of P. radiata and is often highly heritable, offering opl:~rtunities to select and breed for resistance (Simpson et aL 1990b;Burdon et aL 1992;Burdon 1992b). Of the provenances tested in New South Wales for resistance to the foliar pathogen Dothistroma septosporum, Cambria was the most susceptible (Ades et aL 1991). ...
Pinus radiata D. Don, native to a Californian coastal environment, has been introduced to many parts of the world as an exotic species for afforestation. It is now a major plantation species in the Southern Hemisphere. In 1990, it was introduced to the heavily degraded, dry Min river valley area in Aba prefecture of Sichuan Province, P. R. China. Survival and growth of young trees planted at several sites appear to be reasonable. This review is to serve as an introduction to the large body of literature on P. radiata for forest scientists in China. It covers the following aspects: P. radiata in its native environment and in ex situ plantations, provenance and genetic variations, environmental limitations and climate niche, diseases and pests, lessons from unsuccessful introductions, and the use of P radiata for ecological restoration. The early growth of P radiata planted in the dry river valley area is briefly described. Potential problems associated with the introduction of P. radiata in Aba and future research needs are also identified.
... Other techniques, such as the use of δ 13 C discrimination may provide a more integrated measure of water use efficiency for the selection of genotypes (Condon et al. 2004). Also, the maturation stages of our families could have biased our results as they probably showed heritable differences (Burdon et al. 1992a, b), despite fact that the trees in our study were "apparently" in the same maturation stage (by visual inspection only) and were still young and short (less than 1 m tall). Thus, it could be important to explore genetic control of WUEi and its genetic association with other leaf traits in response to water stress but combining instantaneous measurements with more integrated measures of water use efficiency, i.e. δ 13 C. De Miguel et al. (2011) detected a moderate broadsense heritability for WUEi in Pinus pinaster Aiton (H 2 = 0.15), and a significant genetic correlation between g s and specific leaf area (SLA), suggesting that selection based on needles with low SLA values will improve WUEi by reducing water losses through stomatal control. ...
Background: Pinus radiata D.Don is in its third generation of selective breeding on contrasting site types in central Chile, creating interest in its responses to selection and any differential adaptation to site types. We studied the phenotypic variability of growth traits, survival and six ecophysiological traits in 30 open- and control-pollinated families, representing two breeding regions and three breeding generations, in a 2-year-old P. radiata field trial on a sandy soil in the Mediterranean drylands of Central Chile. Findings: Growth, survival and the ecophysiological traits did not differ between the regional origin of the breeding populations. However, breeding-generation effects were significant for height and diameter. As expected, growth traits showed progressive improvement with successive generations. Individual-family effects were evident for all traits except one ecophysiological trait. Conclusions: Breeding has evidently improved early growth performance in the field, despite no clear effect of regional breeding population, but no such effects were observed for the ecophysiological traits. Despite the current study demonstrating considerable family variation at age 2 years, it is unclear how these results relate to performance of mature trees in the field.
The imp acts of past and potential insect pests and diseases in New Zealand's radiata pine plantations are reviewed. Invariably their impacts have decreased with time or can be easily managed. Despite past biotic impacts. growth rates have increased over the last 100 years. Pitch pine canker (PPC) is perceived as the greatest new threat. PPC's impact in California, Spain, Portugal, South Africa and Chile suggests that in New Zealand it would become a nursery problem. Radiata pine remains the best medium-density softwood for New Zealand although climate change may alter the site limits. While a biotic catastrophe, despite its low probability, remains an important risk, this risk is outweighed by the opportunity costs and risks associated with diversifying into alternative species. A strong biosecurity infrastructure is vital, as is maintaining a broad genetic base from which to breed resistance. Large plantation estates should develop defensive strategies against new biotic invasions.
Introduction:
In Pinus radiata D. Don, one of the most widely planted pines globally, frost damages plantations at the seedling stage.
Objective:
To determine differences in growth and tolerance to low temperatures of native populations (Guadalupe and Cedros islands) of P. radiata in greenhouse and outdoors conditions, under different levels of soil moisture.
Materials and methods:
Low-temperature tolerance was determined through the damage index (DI) in freezing tests at -12 °C during 4 h. In each environment (greenhouse and outdoors) two soil moisture treatments were defined (irrigation and drought). The DI was evaluated with the method of electrical conductivity in primary needles during winter and spring. The absolute growth rate (AGR) of the terminal shoot was obtained by measuring the total height of the seedlings.
Results and discussion:
Average DI of 50 and 64 % were obtained in winter and spring, respectively. In greenhouse, DI was different (P ≤ 0.05) between populations, being higher in Guadalupe (>59 %) than in Cedros (<42 %), both in winter and spring. Outdoors, Cedros (64.1 %) had a higher DI than Guadalupe (36.5 %) only during winter. DI was similar in both favorable soil moisture and drought conditions. The Guadalupe population presented higher AGRs in both environments and moisture conditions.
Conclusion:
The population of Guadalupe is more sensitive to low temperatures with greater variation in DI, due to its growth dynamics. Differences between populations are useful in the genetic improvement of the species.
When domesticating a plant or animal species, it is useful to know something about the history of that species, and particularly something about the evolutionary forces that may have modified its genes and how alternative versions of its genes (called allelesG) are organised within and among populations. Furthermore, it is useful to know how much of its natural genetic variation is likely to have been included in the populations being domesticated, and which native populations have not yet contributed potentially useful genetic variants to the breeding lines in use. Besides being useful to breeders, such knowledge is often interesting and satisfying in its own right, and we hope you will find that to be the case with radiata pine.
Pinus radiata is the subject of much the largest and longest-running tree breeding programme in New Zealand. Very intensive plus-tree selection began in the early 1950s, the first seed orchard planting was in 1958, and the first orchard seed was collected in 1968. By 1985 seed orchards could meet the national planting needs, which helped prompt an innovative seed certification scheme.
Selection began in local, ‘land-race’ stands. That proved appropriate, but better knowledge led to research on material from the species’ entire natural range and then to further seed importations from natural stands, mainly for future genetic resources.
Initial plus-tree selection largely addressed poor tree form in the central North Island. This led to selecting a ‘short-internode’ (‘multinodal’) branching ideotype, with great improvements in general tree form and substantial gains in growth rate. A distinctive portfolio of several breeds, representing different breeding goals, has since been developed, for the diverse planting sites and the various end products. By contrast, the original regionalisation of seed orchards proved largely unjustified. Despite early research indicating good heritabilities, wood properties have only figured significantly in breeding goals since growers substantially reduced harvest ages, but they are now intensively researched.
The breeding programme was greatly expanded from 1968, to meet the needs of multi-generation breeding. This was one of the programme’s contributions to developing breeding strategy as a discipline, various of which were reflected in the 1986 Development Plan. Industry uptake of tree breeding has since posed challenges in maintaining the genetic variability for a secure, long-term underpinning of the programme.
Special genetic-gain trials were first planted in 1978, to demonstrate and quantify genetic improvement, and to help update forest out-turn predictions. The gains achieved in tree form helped induce New South Wales State to affiliate with the New Zealand programme, following significant earlier contributions of breeding material to Australian breeding programmes.
Improved technologies for seed orchards and vegetative propagation have facilitated development of the breed portfolio and more specific customisation of seedlots. Becoming able to deliver genetic gain through controlled pollination has allowed changes in the structure of the breeding population. Further changes are resulting from an increasing capability to reconstruct pedigrees after open pollination. Developments towards full clonal forestry have faced obstacles, but offer greater genetic gains and a more precise customisation, and clonal forestry is now being vigorously commercialised. Having a single, large Forest Service until 1987 undoubtedly favoured the development of a very strong tree improvement programme. Since then, continuing institutional changes, which are reviewed, have posed numerous challenges.
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