HERITABILITY OF LODGING RESISTANCE AND ITS ASSOCIATION WITH OTHER AGRONOMIC TRAITS IN A DIVERSE SORGHUM POPULATION
Abstract
Random advanced lines from the grain sorghum (Sorghum bicolor L. Moench) population, PP9, were used to partition the genotypic variances of lodging resistance and other agronomic traits into components due to additive and additive x additive genetic effects. In addition, heritabilities, phenotypic and genetic correlations between characters, and expected gains from S(,1) progeny selection were calculated. A hierarchial design employing 260 S(,4) lines tracing back to 65 random S(,1) plants was used. The S(,1) derived families were categorized into three arbitrary height groups, and analysis was conducted over the groups. The characters evaluated were stalk lodging, before and after frost, total lodging (stalk lodging and peduncle breakage) after frost, thickness of third internode rind, diameter of third internode, flowering, yield, and seed weight/panicle. Additive genetic variance was significant for all traits, whereas additive x additive variances were not significant. Narrowsense heritability estimates, calculated using S(,1) progeny as the selection unit, ranged from 0.46 for rind thickness to 0.85 for flowering. Coefficients of variation were large for the lodging estimates. Rind thickness was significantly correlated, -0.46, with stalk lodging (post-frost), whereas internode diameter and flowering were significantly correlated (-0.30 and 0.25) with stalk lodging estimates taken before frost. Although the pre-frost lodging estimate had a significant phenotypic correlation with post-frost lodging, the genetic correlation was not significant. The genes conferring resistance to post-frost stalk lodging and pre-frost stalk lodging are apparently different. All characters except lodging (post-frost) and yield were significantly correlated with flowering. When flowering within years was used as a covariate, heritabilities did not change appreciably. Yield and seed weight/panicle were not significantly correlated with the lodging estimates.
Degree
Ph.D.
Subject Area
Agronomy
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