Effect of indole-3-acetic acid on fruit drop and quality of date palm cultivars

Fruit setting and ripening are the complex processes whose regulation depends on various plant hormones. In present study, effect of indole-3-acetic acid (IAA) on fruit drop and fruit quality of date palm cultivars was assessed during 2011 at Agriculture Research Institute, Rata Kulachi Dera Ismail Khan, Pakistan. Four different levels of IAA (50 ppm, 100 ppm, 150 ppm and 200 ppm) were applied as foliar spray in triplicate to two date palm cultivars (Dhakki and Gulistan) at kimri stage (unripe stage). The experiment was laid out according to randomized complete block design (RCBD) with two factors factorial arrangement. The results revealed that application of IAA significantly (P less than or equal to 0.05) improved the growth and yield components while reduced the fruit drop in both date palm cultivars. Among cultivars, Dhakki showed relatively more fruit length (4.97 cm), fruit diameter (3.03 cm), fruit weight (30.8 g) and pulp weight (29.16 g) when treated with 150 ppm IAA while less fruit drop (23.00%) and higher bunch weight (21.27 kg) were recorded in cultivar Gulistan with application of 150 ppm IAA. Cultivars effect was also significant (P less than or equal to 0.05) for fruit drop percentage, fruit length, fruit diameter, fruit weight, pulp weight and bunch weight. In case of interactions, only fruit length and pulp weight was found significant (P less than or equal to 0.05) for both cultivars. Results suggested that application of IAA as foliar spray @ 150 ppm at kimri stage (unripe stage) was found to be effective in minimizing the fruit drop percentage and significantly (P less than or equal to 0.05) improving the yield and fruit quality parameters in both date palm cultivars.