Effect of meteorological factors on fruit maturation and the prediction of optimum harvest for apples

Abstract

Apple maturation was found to be largely governed by meteorological conditions, viz. the temperature and precipitation during the pre-bloom period and the first half of the post-bloom period. The meteorological and physiological factors affecting three strains of ‘Red Delicious’ and ‘Golden Delicious’ apples cultivated in an orchard in the Simla Hills were studied during four consecutive seasons and significant correlations were established. The optimum harvest period was precisely predicted by the meteorological conditions well in advance, and the latter showed significant correlations with the actual optimum harvest period determined by starch pattern index and seed colour index. Based on these meteorological factors, a “key year” concept was evolved to reliably predict the optimum harvest period. Since this concept was based on all the interrelated meteorological conditions, a prediction would be more reliable under varying climatic conditions in any ensuing season if considered for the period of 242 days from November to June.