Phenological behaviour and effect of different chemicals on pre-harvest fruit drop of sweet orange cv. Salustiana

摘要

The paper depicts the phenological behaviour of sweet orange cv. 'Salustiana' and to search out the solution of a serious problem of pre harvest fruit drop. Citrus plants having uniform age and size were selected and shoots were tagged on four sides of the tree. Observations including blooming time, ratio of staminate and pistillate flowers, fruit growth and fruit drop were recorded. Maximum flower drop was observed in west and north side of the canopy, while maximum fruit set was on the east and north side. June drop was highest in the southern and northern sides. To address the problem of pre harvest drop of fruit, foliar sprays of urea (0.5%, 1.0% and 1.5%) and GA3(50 ppm, 75 ppm and 100 ppm) separately as well as in combinations were applied during mid of July and August. Percentage of fruit drop was reduced to the lowest values (1.70 and 2.28) after the first application of GA3 @ 100 ppm, and second application of GA3 @ 50 ppm respectively. Hence GA3 can effectively be used to control fruit drop in sweet orange cv. Salustiana.