Effect of Manual Fruit Thinning and CPPU on the Fruit Yield and Changes in Physico-chemical Composit ion at Harvest and af ter Storage of Allison Kiwifruit

Abstract

The present investigation was carried out in the Kiwifruit Block of Department of Fruit Science, Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni-Solan (H.P.) during the year 2011-12 on 27-year-old Kiwifruit cv. Allison comprising of manual fruit thinning alone and in combination with 5 ppm CPPU. This experiment included 8 treatments viz., control, 5 ppm CPPU, thinning up-to 4 fruits shoot^-1, thinning up-to 4 fruits shoot^-1+5 ppm CPPU, thinning up-to 6 fruits shoot^-1, thinning up-to 6 fruits shoot^-1+5 ppm CPPU, thinning up-to 8 fruits shoot^-1 andthinning up-to 8 fruits shoot^-1+5 ppm CPPU_.  The CPPU (urea based cytokinin) was applied as a fruit dip treatment after 10 days of petal fall. The maximum average fruit weight (105.64 g), length (7.48 cm) and diameter (4.96 cm) were found with manual thinning of 4 fruits shoot^-1 along with dip treatment in 5 ppm CPPU. The highest (16.54 g) % loss in weight was recorded with thinning up-to 6 fruits shoot^-1+5 ppm CPPU). The highest TSS contents (7.78, 15.47%), minimum acidity (1.35, 0.74%), highest total sugars (4.19, 9.88%), maximum TSS acid ratio (5.78, 21.04), highest ascorbic acid (90.13, 64.53 mg 100 g^-1) content at harvest and after storage, respectively, were also found with the treatment T₄. However, the highest (87.26 k vine^-1) fruit yield was recorded in vines, retained with 8 fruits shoot^-1 along with the application of 5 ppm CPPU.