Effect of flower and fruit thinning on maturity, yield and quality of plum (Prunus salicina Lindl) cv. Satluj purple

Chemical thinners namely ammonium thiosulphate (1.5 and 2.5%) at 50 per cent flowering and at full bloom stage; urea (4 and 6%) at full bloom and ethrel (50,100 and 150 ppm) before pit hardening stage of the fruits were applied in plum cv. Satluj Purple. Hand thinning of the fruitlets was done before pit hardening stage. Ammonium thiosulphate at 1.5 per cent was found to be the most effective treatment to reduce the crop load, followed by hand thinning. Maturity was advanced by 2 days with ethrel 100 ppm. Maximum yield, fruit weight, TSS, TSS/acid ratio, total sugars and reducing sugars were recorded with ethrel 100 ppm, followed by hand thinning. Ethrel 100 ppm applied before pit hardening stage was the best treatment as it advanced fruit maturation, reduced the crop load and increased the yield of superior quality fruits. Hand thinning of the fruitlets before pit hardening stage was the next best treatment.