Effect of NAA on fruit drop and quality attributes of litchi (Litchi chinensis)

The study envisaged the effect of synthetic auxin on fruit drop, cracking, yield and quality attributes of litchi (Litchi chinensis Sonn.) cultivars, viz. Dehradun and Calcuttia in sub mountaneous zone of Punjab (India). The experiments were conducted at four locations for both cultivars, during 2021 and 2022. The different concentrations of NAA (10, 20, 30, 40 ppm) along with the control (water spray) were applied 10 days after fruit setting (DAFS). The pooled data of two years revealed that application of NAA (20 ppm) drastically reduced fruit drop, cracking index, enhanced fruit retention and quality attributes, i.e. fruit weight, pulp: stone ratio, TSS and total sugars. Pericarp anthocyanin and; a^*and hue angle (h^*) colour coordinates were also improved with NAA treatments as compared to the control. Fruit yield/plant was better with NAA and it ranged from 5.67 to 19.55 % in ‘Dehradun’ and 7.40 to 17.33 % in ‘Calcuttia’ cultivar over the control. The application of NAA (20 ppm) effectively reduced the incidence of fruit drop, cracking, improving fruit retention and juice quality.