Prediction of apple yield on the basis of tree biometerical parameters

The studies were conducted on three age groups (15–20, 20–25 and > 25 year old) of ‘Royal Delicious’ apple orchards in premier growing areas of Himachal Pradesh. Tree volume, girth, number of primary and secondry scaffolds and bud count on different type of spurs/structures were taken us explanatory variables for regression of yield through principle component and ordinary least square. The regression equations selected through various procedures explained 70 to 74 per cent of the total variation in yield in different age groups. Test of significance showed low discrepancy between predicted and actual values. Furthermore, good forecasting performance of these equation was observed through prediction-realization diagram. It was ranked good also through Theil U statistics.