Effect of genotype × environment interactions on starch physicochemical properties in diverse sorghum germplasm.

Abstract

Genotypic diversity and genotype-environment (G × E) interactions affecting starch quality parameters were investigated in 28 sorghum genotypes over two growing seasons. Starch granule diameter ranged from 3.22 to 29.20 μm. Amylose content effectively distinguished waxy genotypes (∼5%) from non-waxy (∼20-33%) genotypes. Starch phosphorous content ranged widely from 109.26 to 618.06 ppm in environment 1 (E1) and 106.94 to 1753.24 ppm in environment 2 (E2). Starches in E1 had higher gelatinization temperatures but lower enthalpy than those in E2. Dynamic rheological analysis indicated that all starches displayed elasticity-dominated, weak-gel behavior, while steady-shear analysis showed consistent shear-thinning behavior with a flow index <1. Principal component analysis of starch quality parameters revealed 60.0% and 61.9% of total variance for E1 and E2, respectively. In addition, correlation analysis further highlighted a significant negative association between amylose content and crystallinity, thermal/retrogradation properties, and shear-thinning behavior across both environments. G × E results also showed significant impact of growing conditions on sorghum starch phosphorus levels, pasting and thermal properties. Together, these findings provide a foundation for developing improved sorghum cultivars tailored to food and industrial applications.