Fruit drop in litchi influenced by various factors at different stages under Eastern India

An experiment on various litchi genotypes in Bihar conditions was carried out at the ICAR-National Research Centre on Litchi, Muzaffarpur, to evaluate the numerous factors responsible for fruit drop at different phases. The primary focus was on determining the phases at which the largest fruit drop occurs and the factors that contribute to fruit drop. The genotype IC-0615608 had the highest fruit set (71.11%) after one week of pollination, while genotype IC-0615587 had the lowest fruit set (20.45%). The genotype IC-0615585 had the highest final fruit set at harvest (9 weeks), while the genotype IC-0615595 had the lowest (0.81%). Genotypes of litchi linked to several causes showed a significant fruit decline. Improper pollination and fertilization, embryo abortion, seed borer and abscission layer were four factors identified which contributed to fruit drop at various stages. Litchi genotypes have been categorized into three categories (low, medium and high fruit drop) based on severity of fruit drop. Improper pollination and fertilization (up to third week), and embryonic abortion (during fourth week) were the main causes of the initial fruit drop. The seed borer infestation abruptly surged in the fifth week, persisted into the eighth week, and then began to significantly decrease in the ninth week. The eighth week saw the beginning of the abscission layer formation, which was the source of the heavy fresh fruit drop that occurred in ninth weeks. Improper pollination and fertilization followed by embryo abortion and infestation of seed borer were the main causes of fruit drop. Knowing the numerous factors connected with the fruit drop at different phases will assist control it better.