Sunburn and fruit cracking in Litchi (Litchi chinensis Sonn.) cv. 'Rose Scented'

Abstract

Litchi (Litchi chinensis Sonn.) is originally from southern China, but due to its higher adoptability and profitability, it is being cultivated in India. In India, litchi is harvested and sold during April-May and fruits have nutritional and economical values. Litchi cv. 'Rose Scented' is highly preferred in India for its taste, but sunburn and fruit cracking are a major drawback for its cultivation. Studies were conducted to quantify the severity of sunburn and incidence of fruit cracking. Fruits first affected by sunburn and burnt outer skin or peel or cuticle part, later turned into cracking. So sunburn acted as a predisposition to fruit cracking in 'Rose Scented'. Thus, sun burn and cracking can be seen in the same fruit. These types (cracked fruit with sunburn) of fruits were 8.26%, 19.58% and 43.25% in 2017, 2018 and 2019, respectively. Lower thickness of cuticle and spongy layer and higher temperature of fruit surface in burnt and cracked fruit may be accountable for fruit burning and cracking. A close correlation was observed between sunburn, cracking and weather situation over two months. A positive relationship was found between maximum temperature, sunburn and fruit cracking.

Full text

Emer Life Sci Res (2023) 9(2): 260-264 260
emergent
Life Sciences Research
Received: 22 August 2023
Accepted: 08 November 2023
Online: 10 November 2023
Authors:
N. Lal ,
ICAR-Indian Institute of Soil Science,
Bhopal, Madhya Pradesh, India
A. Kumar, S. D. Pandey
ICAR-National Research Centre on Litchi,
Muzaffarpur, Bihar, India
narayanlal.lal7@gmail.com
Emer Life Sci Res (2023) 9(2): 260-264
E-ISSN: 2395-6658
P-ISSN: 2395-664X
DOI: https://doi.org/10.31783/elsr.2023.92260264
Short Communication
Sunburn and fruit cracking in Litchi (Litchi
chinensis Sonn.) cv. ‘Rose Scented’
Narayan Lal, Abhay Kumar, S. D. Pandey
Abstract
Litchi (Litchi chinensis Sonn.) is originally from southern China, but due to its
higher adoptability and profitability, it is being cultivated in India. In India,
litchi is harvested and sold during April-May and fruits have nutritional and
economical values. Litchi cv. 'Rose Scented' is highly preferred in India for its
taste, but sunburn and fruit cracking are a major drawback for its cultivation.
Studies were conducted to quantify the severity of sunburn and incidence of
fruit cracking. Fruits first affected by sunburn and burnt outer skin or peel or
cuticle part, later turned into cracking. So sunburn acted as a predisposition to
fruit cracking in ‘Rose Scented’. Thus, sun burn and cracking can be seen in
the same fruit. These types (cracked fruit with sunburn) of fruits were 8.26%,
19.58% and 43.25% in 2017, 2018 and 2019, respectively. Lower thickness of
cuticle and spongy layer and higher temperature of fruit surface in burnt and
cracked fruit may be accountable for fruit burning and cracking. A close
correlation was observed between sunburn, cracking and weather situation
over two months. A positive relationship was found between maximum
temperature, sunburn and fruit cracking.
Keywords fruit cracking, fruit surface temperature, litchi, sunburn
Introduction
Litchi (Litchi chinensis Sonn.) is nutritious fruit crops but it is very specific in
its climatic requirement and this might be reason for its cultivation in limited
countries. Due to specific climatic demands, litchi is restricted to a few states
with 74 per cent of production in Bihar where millions of people depend on it
for their livelihood. It is also grown on bunds and homesteads which give
additional income. Flowering initiation start in February-March and fruit
maturity in April-May when temperature rise in eastern India and at the same
time sunburn and fruit cracking starts in litchi, which is cultivar specific and
they become the most vulnerable with climate change scenario. Litchi cv.
“Rose Scented” is the most popular and widely cultivated variety in the
country. It is a regular and prolific bearing fruit with pleasant aroma but
highly susceptible to sunburn and cracking. Sunburn and fruit crack are the
main limiting factors in litchi cultivation. The extent of sunburn and cracking
is affected by various climatic factors, nutritional, genetic and soil condition
[1-2]. Damage due to sunburn varies from 0.9-19.13% [3]. Higher temperature
and number of sunny days during fruit growth promote sunburn, while
dreadful sunburn changes the cuticle and damages epidermal and
subepidermal tissues. Low humidity, high temperature and hot wind during
fruit development and maturity stage contribute to this problem. Sunburn and
fruit cracking are major problems in litchi due to global warming due to high
light intensity and temperature. Temperature is one of the main abiotic

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stresses that affect many physiological responses in plants and fruits. Photosystems can be seriously
and irreversibly damaged by excessive heat. In addition, high temperature also causes severe drying and
consequently the skin of the fruit becomes hard and inflexible. Pre-monsoon rains following this high
temperature accelerate the growth processes and expansion of the internal tissues, resulting in cracking of
the inflexible skin of the fruit [4]. Temperature and precipitation also affect the physicochemical and
anatomical characters of fruits. This study was therefore initiated to assess the severity of cracking and
sunburn, and determine the association between sunburn, fruit cracking and environmental stress in litchi
due to changes in climatic conditions.
Methodology
This study was conducted at the National Active Germplasm Site, ICAR-National Research Centre on
Litchi, Muzaffarpur during the years 2017-2019. The study site is situated at an altitude of 210 meter and
recumbent between 26o5’64” N latitude and 85o26’64” E. The experiment site is designated by a humid
subtropical with temperatures ranging from 30°C-43°C during summer and 5°C-10°C during winter. This
region is dry and hot in summers and cool in winters with high precipitation in the monsoon. Rains begins
in the mid of June and continues in considerable force till the middle of September. Four plants of litchi
were randomly selected for observation from fruit set to ripening and twelve trees were considered as
replicates. At the end of May, the number of sunburned, cracked and sunburned broken fruit, and normal
fruit morphology were counted for each tree. Morphological data of normal and cracked fruit were
collected during the 3 years of investigations. Statistical analysis of data was performed using a randomized
block design using SPSS software. Weather data including temperature, relative humidity, wind speed,
sunshine, evapotranspiration, precipitation, and rainy days were recorded during fruit development from
April to May each year. Fruit size (length and diameter) was recorded using a digital calliper, while weight
was measured using a digital pan weighing scale. Five branches were marked in four directions and the
number of sunburned and cracked fruits was computed from each marked branch and converted in on
percentage. Fruit surface temperature (FST) was noted using a probe. The thickness of peel (spongy and
cuticle layer) was measured with a vernier caliper and indicated in millimetre (mm). Total soluble solids
(TSS) were measured using a Hanna Refractometer and titratable acidity (%) was determined [5].
Results and Discussion
Morphological description of sunburn and fruit cracking in litchi cv. 'Rose Scented' fruit is given in Table 1.
Sunburn started very early, 40 days just after fruit set. Sunburn started with the distal end even near the
pedicel, but fruit cracking started with the distal end after two months of fruit set. There is no specific form
of sunburn and fruit cracking, but sunburn predisposes to fruit cracking in litchi cv. ‘Rose Scented’. The
sunburn started from the ventral, distal end and near the petiole and then spread over the entire fruit surface
(Figure 1). In the cracked fruit, the pulps were fully exposed. Sunburn and cracks usually occurred in the
west and south direction due to more hours of light with high intensity of light. Sunburn and fruit cracking
also varied in different years.
Table 1. Morphological description sunburn and fruit cracking in litchi cv. ‘Rose Scented’ fruit in India
Parameters
Sunburn
Fruit cracking
Site of Sunburn/cracking
Distal end, Near peduncle
Distal end
Side of Sunburn/cracking
Ventral
Ventral
Pulp
Never exposed
Exposed
Mean time to start after fruit
set
40 days
62 days
Direction
West and south
West and south

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Figure 1. Sunburn on surface of litchi cv. ‘Rose Scented’
Only sunburnt fruits were recorded highest (42.56%) in 2019 due to higher temperature in this year
(Table 2 and Figure 2) whereas only cracked fruits were highest (2.68%) in 2017 due to heavy pre-monsoon
rains. Cracked fruit with burning were 8.26%, 19.58% and 43.25% in 2017, 2018 and 2019, respectively
(Table 2). Normal and affected fruits morphology was significantly differ (Table 3). Fruit weight, cuticle
thickness, spongy layer thickness and acidity were somewhat lower in sunburned and cracked fruit than in
normal fruit. Higher cuticle thickness was observed in normal fruit as it is reported in fruit cracking tolerant
cultivar [6]. In contrast, stone weight, flesh thickness, FST and TSS were higher in affected fruit. FST was
higher in tolerant genotypes than susceptible ones [7].
Table 2. The incidence of sunburn and fruit cracking in litchi cv. ‘Rose Scented’
Fruit condition
Fruit cracking (%) during different years
2017
2018
2019
Sunburn only
5.58
18.65
42.56
Cracking only
2.68
0.93
0.69
Fruit cracking with sunburn
8.26
19.58
43.25
CD (P = 0.05)
0.124
0.204
0.802
Figure 2. Relation of fruit cracking with climatic factors in Litchi cv. ‘Rose Scented’
Therefore, lower cuticle thickness and spongy layer and higher pulp thickness and FST were
associated with sunburn and cracking. Increasing temperature on fruit surface significantly increased the

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pressure applied by the flesh on fruit skin and reduced the rigidity and toughness of the skin,
thereby increasing the incidence of splitting [8]. In affected fruit, the pulp may be pressed against the skin,
resulting in cracking due to reduced thickness and damage to the cuticle. Acidity was lower in affected fruit
than normal ones and TSS was higher in affected fruits which might be due to moisture losses from pulp
through exposed area to environment.
Fruit cracking was closely related with weather conditions. Fruit cracking was positively correlated
with climatic factors during fruit development period were shown (Figure 2). High temperature promoted
cracking in mango [9]. High temperature, water scarcity and lower humidity increased cracking in orange
[10]. Detailed observation revealed that maximum temperature (34.20 °C, 33.85 °C, 36.85 °C) and fruit
cracking (8.26%, 19.58% and 43.25%) have a positive relationship during the study years (Figure 3).
Cracking in litchi had positive relationship with total sugar and FST [11]. The rapid pulp growth and
colour-breaking in litchi coincides with fruit cracking. However, fruit cracking also occur at green stage in
China and Calcuttia Late litchi. The post-harvest life of cracked fruit is reduced due to infection of
pathogens. Fruit cracking causes huge losses to the litchi growers.
Table 3. Fruits characteristics in litchi cv. ‘Rose Scented’
Fruit
condition
Fruit
weight (g)
Seed
weight (g)
Pulp
thickness
(mm)
Cuticle
thickness
(mm)
Spongy
layer
thickness
(mm)
Fruit
Surface
Temp.
(°C)
Total
Soluble
Solids
(0Brix)
Acidity
(%)
Normal Fruit
21.73
3.78
5.48
1.63
0.14
33.25
19.67
0.38
Sunburnt fruit
21.65
3.75
5.43
1.52
0.12
34.87
20.18
0.35
Cracked Fruit
21.14
3.82
5.62
1.41
0.09
34.82
21.84
0.32
CD (P = 0.05)
NS
NS
NS
0.102
0.008
NS
1.058
0.016
NS- Non significant, Temp.- Temperature
Figure 3. Relation of fruit cracking with temperature in Litchi cv. ‘Rose Scented’
Conclusion
It has been observed that ‘Rose Scented’ was most sensitive to sunburn and fruit cracking. Sunburn
predisposed to fruit cracking in litchi cv. ‘Rose Scented’. The unfavorable weather conditions (higher
temperature, high precipitation and lower humidity) might be a closely related with sunburn and fruit
cracking. Heavy pre-monsoon rain promoted only cracking, not sunburn but higher temperature promoted
both sunburn and fruit cracking. The higher temperature during the fruit growth stage was positively
correlated with sunburn and cracking. The thickness of cuticle and spongy layer were lower in sunburned

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and cracked fruit than normal fruit. Similarly, FST was higher in affected fruit than the normal
fruits.
Acknowledgment
Authors are very much thankful to the Director, ICAR-NRC on Litchi, Muzaffarpur, Bihar for providing all
the facility to complete the works.
Conflict of interest
N. Lal, A. Kumar and S. D. Pandey declare that they have no competing interests.
References
[1] L. Schrader, J. Sun, D. Felicetti, J.-H. Seo, L. Jedlow and J. Zhang (2003). Stress-induced disorders:
Effects on apple fruit quality. Washington tree fruit postharvest conference, 2nd – 3rd December.
[2] E. S. Marboh, A. K. Gupta, N. Lal, S. D. Pandey and V. Nath (2018). An overview of differential
response of litchi trees to water stress. Int. J. Innov. Hortic., 7: 17-26.
[3] G. Singh, V. Nath, S. D. Pandey, P. K. Ray and H. S. Singh (2012). Cultivars and genetic enhancement.
In: The litchi. M. K. Papademetriou and F. J. Dent (Ed.), Food and Agricultural Organization of the
United Nations, New Delhi, India, pp18-24.
[4] D. Holland, K. Hatib and I. Bar-Yaakov (2009). Pomegranate: botany, horticulture, breeding. Hortic.
Rev., 35: 127-191.
[5] S. Ranganna (1977). Manual of analysis of fruit and vegetable products. Co., Ltd., New Delhi, Tata
McGraw-Hill Pub, pp634.
[6] N. Lal, N. Sahu, A. Kumar and S. D. Pandey (2022). Effect of rainfall and temperature on sun burn and
fruit cracking in litchi. J. Agrometeorol., 24: 169-171.
[7] N. Lal and N. Sahu (2022). Screening of litchi (Litchi chinensis Sonn.) genotypes against sun burn.
Bangladesh J. Bot., 51: 37–43
[8] A. Lang and H. During (1990). Grape berry splitting and some mechanical properties of the skin. Vitis,
29: 61-70.
[9] P. L. Saran, R. Kumar, S. Ercisli and R. Choudhary (2015). Fruit cracking in mango (Mangifera indica
L.) cv. ‘Dashehari’. Erwerbs-Obstbau, 57: 93-96.
[10] L. U. Opara, C. J. Studman and N. H. Banks (1996). Fruit skin splitting and cracking. In: J. Janick (Ed.),
Horticultural Reviews. pp217-262.
[11] N. Lal, Kumar A. Kumar, S. Pandey and V. Nath (2023). Screening of litchi genotypes for fruit cracking
and the relationship of cracking to fruit and leaf traits. Erwerbs-Obstbau, 65: 479-485.