Department of Pomology, Dr Y.S. Parmar University of Horticulture and Forestry, Solan 173 230
* Assistant Scientist, Regional Horticulture and Forestry Research Station, Bhota, Hamirpur 176 041
Studies were conducted during 1994–96 on Royal Delicious apple spaced at 7–8 m in private orchards with uniform cultural practices in Kotkhai region of Himachal Pradesh (1500–2000 m above mean sea-level). The tree yield of selected age groups (15–20, 20–25 and >25 years) was found to be influenced significantly by number of secondary scaffolds, trunk girth, tree volume and flowering intensity. Yield forecasting regression equations developed on the basis of these variables, for different age groups, through principle component regression gave better precision of the estimate and showed good forecasting performance.
