Influence of exotic rootstocks and cultivars of apple on seasonal nutrient dynamics

A study was aimed to investigate the influence of leaf nutrient concentrations among different exotic cultivars on various rootstocks and fruit quality parameters for two consecutive years. The other goal of the experiment was to precise the time of leaf sampling in four apple cultivars. Among rootstocks MM106 had the highest level of nutrient concentrations whereas M9 had the lowest. Cooper IV recorded the maximum leaf magnesium content and minimum leaf magnesium content was observed in Vista Bella, where as highest leaf boron content was recorded in Vista Bella and minimum was recorded in Cooper IV. The seasonal variation of leaf nutrient concentrations during growth period indicate that early maturing cultivars viz. Vista Bella and Mollies Delicious recorded increase in nutrient content upto 30th June, thereafter the trend decreased, while as the mid-season cultivars viz. Starkrimson and Cooper IV observed a similar trend upto 15th July and decreased thereafter. The seasonal variation of nutrients in leaves indicate stability period of leaf magnesium and boron in early maturing cultivar viz, Vista Bella was observed on 15th of June to 15th of July and in Mollies Delicious was observed on 30th of June to 30th of July, while as in mid season cultivars like Starkrimson and Cooper IV it was observed on 15th of July to 15th of August, indicating proper time for leaf sampling in early and mid season cultivars with respect to leaf magnesium and boron content. It was also observed that fruit L/D ratio, fruit volume, total sugar, TSS and TSS acid ratio was significantly influenced by rootstocks and cultivars. Whereas, titrable acidity didn’t showed any significant variation.