Fruit Retention in Different Litchi Germplasm Influenced by Temperature

Abstract

Individual panicles produce hundreds of pistillate flowers, but only a small proportion of which set fruit and reach at maturity. There are many stages of fruit drop during growth and development caused by different factors. Different factors are associated with different stages of fruit drop. The most common drop is just after fruit set and direct economic losses at pre-harvest drops. Certain cultivars shed fruit more severely than others. The causes of early fruit drop are numerous including lack of pollination, self-incompatibility, failure of fertilization, embryo abortion and competition among developing fruit, insect pests and diseases and climatic condition resulting in internal nutritional and hormonal imbalances. Varietal differences can also be noticed in the pattern of fruit drop. Therefore, a trial was carried out at ICAR-NRC on Litchi to see the response of fruit set in different germplasm and stages of fruit drop in response to temperature. Main emphasis was given to find out the stages at which maximum drop of fruits takes places. Maximum fruit set (76.47 %) was recorded in Ellaichi whereas lowest was observed in shahi during first week after blooming but maximum fruit retention percentage was reported in Deshi (1.49) while lowest was found in dehradoon (0.3 %). The maximum fruit drop was recorded in Ellaichi (66.18%) between 1st and 2nd week, although fruit drop was very high during this period range from 14.72 to 66.18%. Subsequently dropping of fruits were decreased till harvesting but suddenly increased during the period between 4th to 5th and 7th to 8th week due to fluctuation of maximum and minimum temperature.