Effect of growth regulators on pre-harvest fruit drop in plum (Prunus salicina L.) cv. Satluj Purple

Growth regulators viz., ethrel, NAA and GA were sprayed at different stages of fruit development to prevent the pre-harvest fruit drop in plum cv. Satluj Purple. Single spray of ethrel (50 and 100 ppm) was given during fourth week of March and first and second week of April. NAA (10 and 20 ppm) was sprayed twice during second and fourth week of April and GA (50 and 100 ppm) once during first week of March. Ethrel (100 ppm) applied during fourth week of March was the most effective treatment to reduce the pre-harvest drop followed by NAA (10 ppm). The fruit retention; yield, fruit weight and total soluble solids were significantly higher with ethrel (100 ppm) applied during fourth week of March. The acid content was significantly lesser with ethrel (100 ppm) applied during fourth week of March during the both experimental years. Nitrogen content in leaves and shoots was maximum with ethrel (100 ppm) applied during second week of April. The highest carbohydrate content in leaves and shoots was recorded in NAA (10 ppm).