Effect of paclobutrazol on flowering in “China” litchi (Litchi Chinensis Sonn.)

In a field trial on litchi trees cv. china, paclobutrazol was applied in the rhizhosphere @ 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 g a.i./m radius of tree canopy. The chemical was applied once in November 2000, approximately 3 months ahead of panicle emergence to induce flowering. The treatment significantly restricted vegetative flushes before panicle emergence and increased percentage of terminal branches which could in turn produce flowering shoots. Amongst various doses 3.0 g a.i./m radius of a tree canopy was found to be most effective. The response was poor in the fruiting season of 2001 as the trees continued to be vigorously vegetative with limited floral panicles in spite of the treatment. The fruit yield was almost negligible this year. However, the effect of the chemical was carried over to the next flowering season as there was marked difference in the yield between the treated and untreated trees. A yield gain of 52 per cent was recorded in the second year due to the treatment.