EFFECT OF FOLIAR APPLICATION OF NAA ON FRUIT DROP, YIELD AND PHYSICO-CHEMICAL CHARACTERISTICS OF GUAVA (PSIDIUM GUAJAVA L.) RED FLESH CULTIVAR.

A study was conducted in the Department of Horticulture, Agriculture Faculty, Gomal University, D.I. Khan, Pakistan during 2005. NAA (naphthalene acetic acid) @ 0, 15, 30, 45, 60, 75 and 90 ppm concentration was sprayed on summer crop of 28 trees of guava (cv. Red Flesh) at two fruit development stages (marble and walnut stage). Results revealed that NAA significantly reduced pre-harvest fruit drop. Maximum reduction (8.83%) in fruit drop was observed with 45 ppm/spray followed by 30, 60, 75 and 90 ppm. Fruit yield was significantly increased by NAA application. Maximum yield (44.80 kg per treatment) was recorded in case of 45 ppm closely followed by 60 ppm (44.60 kg). Significant variation was observed among various quality parameters i.e. pulp/seed ratio, TSS, total sugars, acidity and ascorbic acid contents in fruits of different treatments. NAA application increased all these ingredients except acidity which was reduced. Maximum pulp/seed ratio (11.31), total soluble solids (11%) and total sugars (7.45%) were recorded in 45 ppm treatment. The same treatment proved as most effective in reducing fruit drop and produced better quality fruit than all other treatments. At higher concentrations fruit quality was inferior. Fruit drop exhibited negative correlation with all other characteristics except acidity whereas pulp seed ratio had positive correlation with TSS, total sugars and ascorbic acid contents and negative association with acidity. [ABSTRACT FROM AUTHOR]