Tomar, C.S.Vijay Kumar2017-06-032017-06-032012http://krishikosh.egranth.ac.in/handle/1/5810016885The present investigations entitled “Studies on fruit development, leaf nutrient status and harvest maturity of nectarine” were carried out at the experimental orchard of Department of Fruit Science, Dr. Y S Parmar University of Horticulture and Forestry, Nauni, Solan, (HP) during 2010 and 2011. Six year-old nectarine plants of two cultivars namely, Silver King and Snow Queen raised on wild peach seedling rootstock were selected on the basis of uniform vigour. The plants were planted at a spacing of 3 x 3 meters and trained to open centre system. The whole program of study was split into two experiments. First experiment was laid out in Randomized Block Design to elucidate the seasonal variations in vegetative characteristics, fruit parameters and leaf nutrient status in both the cultivars . The second experiment was conducted to standardize the optimum harvest maturity for these cultivars. The observations on seasonal variation in various characteristics were recorded on 11 sampling dates beginning with 7 DAFB upto 77 DAFB. It was revealed that fruit growth as measured in terms of fruit weight, fruit size and fruit volume exhibited characteristic of double sigmoidal curve. The pattern of growth resulted in a period of rapid growth for 28 days (stage I) followed by slow growth for 21 days (stage II) and again exhibited rapid growth (stage III) in both the cultivars viz., Silver King and Snow Queen. Among the vegetative parameters, number of shoots per branch increased significantly upto 42 DAFB. However, shoot extension growth, tree volume, leaf area, number of leaves per shoot and leaf/fruit ratio exhibited significant increase upto 49 DAFB. The fruit quality parameters viz., total soluble solids, total sugars, reducing sugars and non -reducing sugars increased rapidly from 49 DAFB to 70 DAFB in both the cultivars. In correlation study, number of shoots per branch, number of leaves per shoot, leaf area had significant positive correlation with fruit size, fruit weight and fruit volume. Seasonal variation in leaf N, K, Ca, Mg, Mn and Fe had positive and significant correlation with fruit quality parameters, whereas leaf P, Zn and Cu had negative and significant correlation with fruit quality parameters. The present investigation revealed that the harvesting of nectarine should be done on or around 23 rd to 26 th May in cultivar Silver King and 30 th May to 2 nd June in Snow Queen under midhill conditions of Himachal Pradesh. In terms of days from full bloom (DAFB) to harvest, these calendar dates corresponded to 72 to 75 days and 73 to 75 days for Si lver King and Snow Queen cultivars, respectively. On the basis of consistency in the results, DAFB, total soluble solids, total sugars and reducing sugars were found to be reliable indices of maturity for nectarine fruits.enFruit development, Leaf nutrient, NectarineThesis