DELAYING THE RIPENING OF 'BOMBAI' LITCHI

The litchi industry in the state of West Bengal, India, is based on the cultivar ‘Bombai’. The harvest season lasts for only 15-20 days in the month of May. During peak harvest, the price is slashed markedly and, due to inadequate postharvest infrastructure, a sizable quantity of litchi gets wasted. The aim of this study was to test several methods of delaying ‘Bombai’ fruit maturation and ripening to extend the harvesting period. We investigated two shading treatments (30 and 50%) and spraying with GA₃ (50, 100 and 200 mg L^-1) and KNO₃ (4%) at different stages (on 1 cm panicle and at 15, 21 and 28 days after anthesis) were also evaluated. The results revealed that spraying of 50 mg L^-1 GA₃ at 15 or 21 days after anthesis or shading the trees using agronet (30 and 50% light transmission) at 30 days before expected harvesting delayed the harvesting by about 5-8 days. Two sprays of 4% potassium nitrate (KNO₃) 15 days after anthesis resulted in the highest fruit weight (25.8 g). The quality of fruit (in terms of TSS/acid ratio) was recorded best when 4% KNO₃ was sprayed once at 21 days after anthesis.