Physiological adaptability of sweetpotato (Ipomoea batatas) genotypes as influenced by seasons with emphasis on orange-fleshed sweetpotato

Abstract

A field experiment was conducted during both rainy (kharif) and winter (rabi) seasons of 2007–08 to determine the physiological basis of yield variation comprising six sweetpotato (Ipomoea batatas) genotypes. The improved whitefleshed sweetpotato genotype ‘CIP-SWA 3’ out yielded all the other genotypes in both the seasons. However, among the orange-fleshed sweetpotatoes, ‘IB 97-6/15’ and ‘IB 97-2/5’ were the second best. In kharif, yields were constrained by excessive vine length, greater leaf number and leaf area, lowered biomass with reduced partitioning of dry matter to tubers. A general reverse trend in these characteristics induced higher yields in rabi. In both seasons, the local variety followed by ‘CIP SWA 3’ recorded relatively better crop growth characteristics. Early tuberization was chiefly responsible for higher yields in rabi. Further despite low leaf area index values, a higher photosynthetic efficiency in terms of net accumulation ratio, followed by higher bulking rate and partioning coefficient values resulted in higher yields during rabi.