Genetic analysis of kernel modification in Quality Protein Maize (QPM) genotypes

Abstract

Kernel vitreousness, besides agronomic performance and endosperm protein quality, is important for the successful adoption of the Quality Protein Maize (QPM) genotypes. The present study was undertaken to analyze in detail different attributes of kernel modification (endosperm modification, crown opaqueness and ear appearance) in QPM inbred lines and a set of experimental crosses (7 x 7 full diallel). Significant differences among the QPM genotypes for kernel modification were observed in the diallel set, indicating segregation of several kernel modifier genes. Correlation analysis revealed significant and positive associations among endosperm modification, crown modification as well as ear appearance under openpollination. Analysis of ears obtained from different pollination modes (open vs. controlled-pollination) indicated significant interaction of the genotypes with the pollination mode, suggesting the importance of the source of pollen and its genetic constitution in conferring the kernel texture. The diallel analysis also indicated almost equal contribution of additive and non-additive effects for endosperm modification; however, there was predominance of non-additive gene effects on crown modification and ear appearance. Reciprocal cross differences for kernel modification in the diallel set were also observed, suggesting the possible dosage effects of the endosperm modifiers. Overall, for analysis of combining ability and for estimation of genetic variance components in relation to kernel modification in the QPM genotypes, experiments employing controlled-pollination mode could be more reliable than those using the openpollination mode.