Regression analysis of apple yield on the basis of some morphological and nutritional parameters

The studies were conducted on the age groups (15–20, 21–25 and > 25 years) of Royal Delicious apple orchards at Jubbal, Mashobra, Seobagh and Bajaura locations. Yield was influenced significantly by growth, volume, secondary spurs, flowering and fruit set at Mashobra location i.e. the increase in these plant parameter proportionally increased the yield but primary spur has no effect on yield. 73 per cent of the total variation in yield was explained by variables included in the function. At Jubbal yield was influenced significantly by all the parameters except primary spur and flowering. 64 per cent of the total variation in yield was explained by variable included in the function. 62 and 55 per cent of the total variation in yield was explained by variables included in the function at Seobagh and Bajaura, respectively. The yield was affected by proportion of reproductive buds in spur categories S2 and S4 under Mashobra and Jubbal locations. Explanatory variable (the variable which influences the value of dependent variable, used for prediction and also known as regression or independent variable) included in the function have explained about 65% and 71% of total variation in the yield at Mashobra and Jubbal; respectively. At Seobagh, variables included in the function have explained about 76% of total variation in yield. At Bajaura, variables have explained 62% of total variation in the yield. Yield was affected significantly by leaf N, P, K, Ca and Mg at Jubbal and Seobagh and the explanatory variable included in the function have explained about 81% (Jubbal) and 89% (Seobagh) of total variation in the yield. Under Mashobra and Bajaura conditions, explanatory variables have explained 78% and 74% of the total variation in the yield.