The Effect of Some Growth Regulators and Ascorbic Acid to Improve Fruit Quality of Balady Guava Trees Growing in Sandy Soils

Abstract

The present study was carried out during 2017and 2018 seasons on 10 years old Balady guava trees (Psidium guajava L.) grown at private orchard located on "Cairo-Alexandria Desert" road about 49 Km from Cairo, Egypt. Trees planted at 4 × 4 meters apart in sandy soil under drip irrigation system. The aim of this work was improving fruit quality of Balady guava trees by gibberellic acid (GA3),
benzyladinine (BA) and ascorbic acid. Gibberellic acid and benzyladinine were used as a spray at rate (50 and 100 ppm) were applied twice the first one after 80% at full bloom, and the second time after 10 days later, ascorbic acid at rate (200 and 400 ppm) spraying twice in June and before collected with a month. The experimental treatments were arranged in Randomized Block Design with three replications for each. The results were summarized that: All treatments significantly improved characteristics of vegetative growth, physical parameters, biochemical characteristics and yield. The results cleared that gibberellic acid (GA3) and benzyladinine (BA) foliar spray induced a positive effect on leaf characteristics (leaf area and total chlorophyll content), Shoot length, number of fruits / tree, yield, fruit weight, pulp %, fruit length, fruit diameter and reduced seed %. The highest values were recorded under foliar application of 100 ppm gibberellic acid or benzyladinine. Quality parameters namely total soluble solids, total acidity content, total sugar (%) and fruit ascorbic acid content than the control treatments were also found to be improved with ascorbic acid at 400 ppm. It may be recommended the application of gibberellic acid or benzyladinine at 100 ppm and 400 ppm Ascorbic acid in order to enhance yield,
fruits quality, high suitable for marketability in local or export markets comparison to untreated plants (control) and other application.