Evaluation of Physical Grain Quality in the BS17 and BSI (HS)CI Synthetics of Maize1

Abstract

The objective of this study was to determine the potential for selection of maize (Zea mays L.) genotypes that produce grain resistant to physical injury and to study relationships among physical grain traits during inbreeding. Materials evaluated were S1 and S2 lines derived from BS17 and BSI(HS)C1. Eight traits (kernel shear strength, visual endosperm rating, date of anthesis, grain harvest moisture, grain‐breakage susceptibility, weight per 300 kernels, volume per 300 kernels, and kernel density) of BS 17 S1 and S2 lines were evaluated in 1979 and 1980, respectively, and of BSI(HS)CI S1 and S2 lines in 1980 and 1981, respectively. All materials were grown at two locations. The analyses of variance combined over environments revealed that significant genetic variability among genotypes existed for all traits. Genotype ✕ environment interactions were generally significant for all traits except shear strength and kernel density. Estimated genotype ✕ environment interaction variance components were 0 to 66% as large as estimated genotypic variance components. Variance component heritability estimates (entry‐mean basis) for grain breakage ranged from 0.48 to 0.73. The optimum harvest moisture range for preservation of physical grain quality was 19 to 26%. Deviations from this optfimum grain moisture range resulted in increased grain breakage susceptibility. Grain resistant to breakage tended to be smaller, denser, and higher in shear strength. Correlations between traits indicated that entry means of S1 line traits would have predictive value for the same traits of the S2 lines. The data indicated that selection of S2 lines for breakage‐resistant grain would cesult in earlier‐flowering S2 lines with smaller kernels.