Influence of growth regulators on setting, retention and weight of fruits in two cultivars of litchi

Abstract

Investigations were undertaken to explore the possibility of improving setting, retention and weight of fruits in ‘Early Seedless’ and ‘Calcuttia’ cultivars of lichi ( Litchi chinensis) by means of growth regulators. Indole acetic acid (IAA) at 20, 40 and 80 mg l −1, 2,4-dichlorophenoxy acetic acid (2,4-D) at 2,4 and 8 mg l −1 and gibberellic acid (GA 3) at 50, 100 and 150 mg l −1 were sprayed on panicles in the first fortnight of April, when 50–100% flowers had opened. All 3 growth regulators caused a favourable effect on fruit setting, fruit retention and weight of individual fruits, but IAA at 20 mg l −1 proved the best for enhancing setting, GA 3 at 50 mg l −1 for increasing retention and GA 3 at 100 mg l −1 for improving fruit weight. IAA and GA 3 should, therefore, be used in combination. Between the 2 cultivars tested, ‘Calcuttia’ proved superior to ‘Early Seedless’ in fruit setting, fruit retention and weight of individual fruits.