Effect of NAA and CPPU on Fruit drop, Yield and Quality of Avocado Trees

Abstract

This work conducted to investigate the effect of NAA and CPPU on fruit set and retained/panicle, accumulative and relative fruit drop %, fruit quality and yield, changes in total soluble sugars on Bacon avocado (Persea Americana Mill.) trees. The selected trees were foliar sprayed twice, at full bloom and beginning of fruit set, with one of the following treatments, water (control), NAA at 15 or 30 ppm, CPPU at 5 or 10 ppm, and their combinations. Avocado trees treated with 30 ppm NAA + 5 ppm CPPU resulted in the highest fruit set/panicle, fruit retained/panicle and significantly reduced the peak of fruit drop happen 2 weeks after fruit set. Also, 30 ppm NAA + 5 ppm CPPU and 5 ppm CPPU produced the highest fruit weight, fruit dimension and yield. All the treatments with NAA or CPPU significantly decreased the content of total soluble sugars in the leaves from the 3rd to 8th weeks after fruit set and starch from the 1st to 3rd week after fruit set. Based on this study, NAA and CPPU promoted the mobilization of carbohydrate from the leaves to the fruitlet. Hence, NAA or CPPU suppressed fruit drop in avocado by increasing the availability of carbohydrate in fruitlet and thus improved fruit retention.