Relationship of Fruit Calcium Content, Fruit Pressure at Maturity and Tubercle Density with Cracking and Sun-Burning in Fifteen Litchi Cultivars of West Bengal, India D. Mandal a Department of Horticulture Aromatic and Medicinal Plants School of Earth Sciences and Natural Resources Management Mizoram University Aizawl 796004, Mizoram India S.K. Mitra Faculty of Horticulture Bidhan Chandra Krishi Viswavidyalaya Mohanpur 741252 Nadia, West Bengal India Keywords: pericarp, aril, calcium, fruit cracking, sun-burning, varietal difference Abstract Litchi is one of the important subtropical fruits of the Sapindaceae family grown in India in States like Bihar, West Bengal, Uttarakhand, Tripura, Punjab, etc. In West Bengal, litchi cultivars suffer from sun-burning and fruit cracking disorders which cause 10-15% fruit loss to the growers. The present study was taken up to identify the relationship of fruit (aril and peel) calcium content, fruit pressure and tubercle density with fruit cracking and sun-burning in 15 litchi cultivars. Results revealed that among the fifteen cultivars in the study Bedana, Bombai, Elaichi, Kasba, Nafarpal, Piazi and Seedless Late showed less amount of fruit cracking and sun-burning (<5%); while cultivars like China, Deshi, McLean, Early Muzaffarpur, Muzaffarpur, Purbi and Rose Scented showed higher percentages of cracking and sun-burning in fruits (>10%). In general, calcium content in the pericarp was found higher than in the aril of the fruit. Besides, normal fruit contained more calcium in the aril and pericarp than in cracked and burnt fruits. Cultivars like Bedana, Bombai and Kasba showed higher aril and pericarp calcium and less fruit cracking and burning. The cultivars McLean, China and Deshi showed higher percentages of fruit cracking and burning even though the aril and pericarp calcium contents were higher. Correlation study revealed no significant relationship between fruit cracking and sun-burning and calcium content in fruit aril and pericarp. In general, fruit pressure at maturity and tubercle density was higher in cracked and burnt fruits. Among the cultivars, Bedana and Seedless Late showed lower tubercle density (4.66 and 6.25 cm -2 ) and less cracking (4.70 and 5.66%). INTRODUCTION Litchi (Litchi chinensis) is a deliciously juicy fruit with attractive red colour belonging to the Sapindaceae family which originated in South China (Batten, 1984) and is considered to have reached eastern India through Myanmar by the end of the 17 th century (Singh and Babita, 2002). India is the second largest producer of litchi after China and its production is restricted to the States like Bihar, West Bengal, Uttarakhand, Punjab, Assam and Tripura. Like in China (Chen and Huang, 2001), Thailand (Sethpakdee, 2002), Nepal (Budathoki, 2002) and South Africa (Joubert, 1970), the major hindrance in successful litchi cultivation and quality fruit production in India is fruit cracking and sunburning (Mitra and Ghosh, 1991). A survey in China indicated that the cultivar Nuomici suffered yearly 20-50% losses equivalent to US$ 2-3 million (Li and Huang, 1994) due to this disorder. In India, fruit cracking in some susceptible cultivars like Muzaffarpur and Dehradun was reported to cause over 30% of crop loss (Kanwar et al., 1972). In West a debashismandal1982@gmail.com Proc. Fourth IS on Lychee, Longan and Other Sapindaceae Fruits Ed.: R. Cronje Acta Hort. 1029, ISHS 2014 209
Bengal, the most popularly grown cultivar Bombai faced 10-15% crop loss due to fruit cracking in different years (Ghosh and Mitra, 2000). Researchers have reported that calcium has a profound relationship with the occurrence of this disorder as it is a major constituent of cell walls which is further related to pericarp structure, tensile strength and development of spongy tissue, which is thought to buffer the exerting pressure of faster developing aril (Brett and Waldron, 1990; Huang et al., 2001, 2004a,b). Li and Huang (1995) stated that developing aril pressure when exceeding the pericarp tensile strength caused fruit cracking. Moreover, Kanwar et al. (1972) depicted the relationship of tubercle density with fruit cracking response in some of the Indian cultivars. These comprehensive reviews of research created a scope to study and investigate the relationship of fruit cracking and sun-burning with fruit calcium content, fruit pressure at maturity and tubercle density. Fifteen litchi cultivars were used to investigate these relationships. MATERIALS AND METHODS The experiment was carried out at the Horticulture Research Station of the Faculty of Horticulture, Bidhan Chandra Krishi Viswavidyalaya situated at Mondouri, Nadia, West Bengal during 2008-2010. The research station is situated at 23.5 N latitude and 89 E longitude having an altitude of 9.75 m above mean sea level. The place has a tropical climate with an average annual rainfall of 1457 mm and mean temperature ranging from 18.45 C (minimum) to 31.02 C (maximum). The soil of the experimental site was sandy loam in texture with moderate water holding capacity and a ph of 6.8. Twenty-six-year-old litchi trees of 15 cultivars viz., Bedana, Bombai, China, Deshi, Early Large Red, Early Muzaffarpur, Elaichi, Kasba, McLean, Muzaffarpur, Nafarpal, Piazi, Purbi, Rose Scented and Seedless Late which were planted at 8 8 m spacing in a randomized block design with three replications, were used for the experiment. The fruit aril and pericarp calcium content was determined by complex metric titration with Na-EDTA (Black, 1965). Fruit pressure was measured by penetrometer (Wagner Instruments, USA). Observations were made on percentage of fruit cracking and sun-burning at harvest, relationship between pulp and pericarp calcium contents and sun-burnt and cracked fruits, and relationship of tubercle density and fruit pressure with sun-burnt and cracked fruit. RESULTS AND DISCUSSION Perusal of data revealed that out of the 15 cultivars used in this investigation, Nafarpal showed minimum fruit cracking (2.06%) and Bedana showed minimum sunburning (2.34%) of fruit at harvest. Maximum fruit cracking (19.0%) and sun-burning (22.4%) were recorded in cultivars Rose Scented and Purbi, respectively. From the data presented in Table 1, it may be summarized that Bedana, Bombai, Elaichi, Kasba, Nafarpal, Piazi and Seedless Late were less susceptible (<5%) to this malady. Cultivars like China, Deshi, McLean, Early Muzaffarpur, Muzaffarpur, Purbi and Rose Scented, however showed higher percentages of cracking and burning of fruits (>10%). The finding has close similarity with the earlier findings of Pereira et al. (2005). In general calcium content in the pericarp was found higher than in the aril of the fruit. Besides, normal fruit contained more calcium in aril and pericarp than cracked and burnt fruits (Table 2). However, cultivars like Bedana, Bombai and Kasba showed higher aril and pericarp calcium contents and less fruit cracking and burning. Li and Huang (1995) reported after their study with pericarp morphology in relation to fruit cracking susceptibility in litchi that calcium contents in the pericarp of un-cracked fruits were significantly higher than those of cracked fruits. Ou (1988) stated that calcium increased critical cracking turgor and pericarp tensile strength. It was also revealed from the study that McLean, China and Deshi showed higher percentage of fruit cracking and sun-burning even though the aril and pericarp calcium contents were higher. After the 210
X-ray microscopic analysis of calcium in the pericarp of cracking resistant Huaizhi and susceptible Nuomici, Huang et al. (2001) reported that a large number of calcium rich cells were present in the epidermis of Nuomici, but in Huaizhi there were few. Results suggested that there was a difference in the mobilization of calcium to construct cell walls between Nuomici and Huaizhi. Our correlation study however showed no significant coinciding relationship between fruit cracking and sun-burning and calcium content in fruit aril and pericarp (Table 3). This finding is in agreement with the finding of Sanyal et al. (1990). In general, fruit pressure at maturity was higher in cracked and sun-burnt fruit than in normal fruit at harvest (Table 4). The cultivars Bedana, Bombai, Elaichi, Kasba, Nafarpal and Piazi showed less fruit pressure (<3.5 kg cc -1 ) in cracked and burnt fruit, while in Rose Scented, Purbi, Muzaffarpur, McLean and Early Muzaffarpur, which are more susceptible to these disorders, the fruit pressure was recorded high. Huang (2005) reported that fruit cracking occurred in litchi when the pressure of extending aril exceeds the tensile strength and extensibility of the pericarp. The number of tubercles (cm -2 ) in the pericarp was found less in fruits of Bedana, Bombai, Elaichi, Nafarpal, Piazi and Seedless Late (Table 4) which were found less prone to fruit cracking and sun-burning. Kanwar et al. (1972) indicated that cultivars with relatively thin skin, few tubercles per unit area and flat in shape were less prone to cracking. It may be concluded that fruits with less number of tubercles in the pericarp and having less aril pressure are found less prone to fruit cracking. But the calcium content of fruit aril and pericarp has no coinciding relationship with fruit cracking and sun-burning. Literature Cited Batten, D.J. 1984. Lychee Varieties. Department of Agriculture, New South Wales Agri. Fact. H6.2. 7:1-15. Black, C.A. 1965. Methods of Soil Analysis. American Society of Agronomy, Inc., Madison, USA. Brett, C. and Waldron, K. 1990. Physiology and Biochemistry of Plant Cell Walls. Unwin Hyman, London. Budathoki, K. 2002. Lychee production in Nepal. p.81-93. In: M.K. Papademetriou and F.J. Dent (eds.), Lychee Production in the Asia-Pacific Region. Food and Agricultural Organisation of the United Nations, Bangkok, Thailand. Chen, H.B. and Huang, H.B. 2001. China litchi industry: development, achievement and problems. Acta Hort. 558:31-39. Ghosh, S.P. and Mitra, S.K. 2000. Status Report on Genetic Resources of Litchi in Thailand, India and Myanmar. IPGRI Report, Rome, Italy. Huang, X.M. 2005. Fruit disorders. p.141-151. In: C.M. Menzel and G.K. Waite (eds.), Litchi and Longan: Botany, Production and Uses. CABI Publishing, Oxfordshire, UK. Huang, X.M., Li, J.G., Wang, H.C., Huang, H.B. and Gao, F.F. 2001. The relationship between fruit cracking and calcium in litchi pericarp. Acta Hort. 558:209-216. Huang, X.M., Yuan, W.Q., Wang, H.C., Li, J.G. and Huang, H.B. 2004a. Early calcium accumulation may play a role in spongy tissue formation in litchi pericarp. J. Hort. Sci. Biotech. 79(6):947-952. Huang, X.M., Yuan, W.Q., Wang, H.C., Li, J.G., Huang, H.B., Shi, L. and Jinhua, Y. 2004b. Linking cracking resistance and fruit desiccation rate to pericarp structure in litchi (Litchi chinensis Sonn.). J. Hort. Sci. Biotech. 79(6):897-905. Joubert, A.J. 1970. The Litchi. Government Printer, Pretoria, South Africa. Kanwar, J.S., Rajpoot, M.S. and Bajwa, M.S. 1972. Sun-burning and skin-cracking in some varieties of litchi (Litchi chinensis Sonn.) and the factors affecting them. Indian J. Agric. Sci. 42:772-775. Li, J.G. and Huang, H.B. 1994. Analyzing the cause of fruit cracking increased by rain after a long period of drought. p.361-364. In: K.S. Cheng and S.L. Zhang (eds.), Advances in Horticulture. Agricultural Publisher, Beijing, China. 211
Li, J.G. and Huang, H.B. 1995. Physico-chemical properties and peel morphology in relation to fruit-cracking susceptibility in litchi fruit. J. South China Agric. Univ. 16:84-89. Mitra, S. and Ghosh, B. 1991. Description and performance of some litchi cultivars in West Bengal, India. Aust. Lychee Growers Assoc. Yearb. 1:64-79. Ou, L.X. 1988. Studies on fruit cracking in Litchi chinensis Sonn. Master Thesis. South China Agricultural University, Guangzhou, China. Pereira, L.S., Pathak, P.K. and Mitra, S.K. 2005. Extent of fruit cracking and sunburning in different lychee cultivars. Acta Hort. 665:141-145. Sanyal, D., Hasan, A., Ghosh, B. and Mitra, S.K. 1990. Studies on sun-burning and skincracking in some varieties of litchi. Indian Agric. 34(1):19-23. Sethpakdee, R. 2002. Lychee production in Thailand. p.106-113. In: M.K. Papademetriou and F.J. Dent (eds.), Lychee Production in the Asia-Pacific Region. Food and Agricultural Organisation of the United Nations, Bangkok, Thailand. Singh, H.P. and Babita, S. 2002. Lychee production in India. p.55-67. In: M.K. Papademetriou and F.J. Dent (eds.), Lychee Production in the Asia-Pacific Region. Food and Agricultural Organisation of the United Nations, Bangkok, Thailand. Tables Table 1. Fruit cracking and sun-burning (%) in different litchi cultivars. Cultivars Average cracking tree -1 Average sun-burning tree -1 (%) (%) Bedana 4.7 1.4 Bombai 4.1 2.0 China 11.3 10.4 Deshi 10.4 10.8 Early Large Red 6.3 4.6 Early Muzaffarpur 18.0 14.5 Elaichi 2.6 2.9 Kasba 4.8 4.1 McLean 17.2 18.7 Muzaffarpur 16.9 19.6 Nafarpal 2.1 2.3 Piazi 4.4 5.4 Purbi 14.2 22.4 Rose Scented 19.0 21.2 Seedless Late 5.7 4.8 212
Table 2. Fruit calcium contents in the aril and pericarp of different cultivars. Cultivars Calcium content of aril (% dry weight) Calcium content of pericarp (% dry weight) Normal Cracked Burnt Normal Cracked Burnt Bedana 0.40 0.33 0.35 2.04 1.73 1.92 Bombai 0.50 0.40 0.46 1.60 1.35 1.52 China 0.48 0.35 0.37 1.54 1.31 1.48 Deshi 0.50 0.29 0.40 1.73 1.48 1.54 Early Large Red 0.50 0.37 0.44 1.90 1.50 1.85 Early Muzaffarpur 0.42 0.33 0.35 1.73 1.52 1.60 Elaichi 0.37 0.31 0.33 1.67 1.35 1.50 Kasba 0.50 0.42 0.48 1.64 1.52 1.64 McLean 0.46 0.33 0.38 1.48 1.21 1.35 Muzaffarpur 0.44 0.33 0.40 1.79 1.35 1.64 Nafarpal 0.38 0.37 0.35 1.69 1.27 1.42 Piazi 0.38 0.37 0.33 1.06 0.89 0.96 Purbi 0.37 0.31 0.31 1.77 1.48 1.62 Rose Scented 0.48 0.37 0.40 1.71 1.42 1.52 Seedless Late 0.37 0.27 0.29 1.54 1.35 1.44 Table 3. Correlation study between calcium content of aril and pericarp with fruit cracking and burning of fifteen litchi cultivars. Correlation Aril calcium vs. cracking Pericarp calcium vs. cracking Aril calcium vs. burning Pericarp calcium vs. burning -0.219* 0.096* -0.103* -0.029* coefficient * non-significant at P=0.05. 213
Table 4. Fruit pressure and tubercles density of different cultivars under study. Cultivar Fruit pressure (kg cm -3 ) Number of tubercles (cm -2 ) Normal Cracked Burnt Normal Cracked Burnt Bedana 3.23 3.33 3.16 4.66 6.00 5.66 Bombai 3.23 3.73 3.10 7.50 8.00 8.50 China 4.23 4.80 4.53 9.50 10.00 10.50 Deshi 4.00 4.20 4.13 9.00 10.66 11.14 Early Large Red 3.23 3.95 3.13 9.33 10.20 11.33 Early Muzaffarpur 4.97 5.13 5.03 9.67 10.45 11.66 Elaichi 3.16 3.60 3.40 6.75 7.00 9.50 Kasba 3.56 4.80 4.00 8.50 8.40 9.60 McLean 4.93 5.36 5.10 8.97 8.82 9.00 Muzaffarpur 5.36 5.70 5.48 8.50 9.50 10.25 Nafarpal 3.43 3.93 3.40 7.56 8.34 8.00 Piazi 3.46 3.47 4.36 7.33 7.56 9.00 Purbi 5.40 5.90 5.80 8.33 9.45 10.46 Rose Scented 5.00 5.43 5.30 8.00 10.50 11.60 Seedless Late 4.30 4.80 4.53 6.25 7.33 7.88 214