Accumulation Dynamics of Starch and Its Granule Size Distribution of Cassava Genotypes at Different Growing Seasons

Abstract

This study aims to evaluate seasonal variation on starch production of different cassava genotypes planted under irrigated condition. Three cassava genotypes (Kasetsart 50, Rayong 11 and CMR38-125-77) were evaluated in two different growing seasons, i.e., early rainy seasons (ERS) and post rainy seasons (PRS) for two years. A randomized complete block design with four replicates was employed in each growing season. The starch yield was more strongly associated with growing season (28.3%), whereas starch content, amylose content, amylose-amylopectin ratio were more associated with genotypes (19.9–30.7%). Planting cassava in the ERS had rapid growth rates of starch yield and granule size in early growth stages, whereas planting cassava in the PRS had rapid growth rates of these traits in the middle to late growth stages. Cassava planted in the PRS had higher starch yield than the ERS for most genotypes except for Rayong 11, which had no significant differences between growing seasons. The yield and content of starch and size of starch granule continuously increased from four to twelve months after planting (MAP) for most cassava genotypes. Unlike other genotypes, CMR38-125-77 in the ERS gave the highest starch yield and its granule at 10 MAP; however, at 12 MAP, it was still higher than other genotypes. CMR38-125-77 was a preferable genotype, since it had a faster rate of starch formation and more starch and amylose contents, as well as starch yield in both ERS and PRS.