Genetic analysis of physical grain quality characters in sorghum

Abstract

Sorghum is grown the world over for both human and animal consumption. Recently, the increase in grain production has slowed; simultaneously, its marketability has declined. Grain size is one of the most important determinants of grain yield and market price in India. One important factor responsible for the decline in consumption of sorghum in India is the inferior quality of rainy season produce. Consumers prefer post rainy season sorghums as the grains are bold, round and lustrous in appearance. Any improvement in the quality of rainy season sorghum grain would help it to fetch higher market prices.In the present study, the genetics of important grain quality characteristics such as grain size, grain shape and lustre were studied using two crosses based on elite sorghum lines 463B and AKMS 14B, and a germplasm line, IS 17600, during 2001 at the National Research Centre for Sorghum, Hyderabad, India. Generation mean analysis and frequency distribution studies revealed that grain size is governed by dominant genes that are polygenic in nature. Predominance of dominance and epistatic interactions in both crosses indicates that selection for higher grain size would be more effective if the dominance and epistatic effects are first reduced by a few generations of selfing. Biparental mating is suggested for developing homozygous bold grain lines. Round grain shape is governed by a single dominant gene and grain lustre by two complementary recessive genes. The study suggested that developing a sorghum hybrid with bold, round grain is feasible provided either of the parents has bold and/or round grain. However, for the hybrid to be lustrous, both parents need to be lustrous and homozygous for the alleles conferring grain lustre at a common locus. With the possibility of development of sorghum hybrids with bold, round and lustrous grain, there is scope for improvement in consumer preference of rainy season sorghum grain.