Heritability of Lodging Resistance and Its Association with Other Agronomic Traits in a Diverse Sorghum Population1
- T. J. Prest,
- R. P. Cantrell and
- J. D. Axtell2
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 ✕ additive genetic effects. In addition, heritabilities, phenotypic and genetic correlations between characters, and expected gains from S1 progeny selection were calculated. A hierarchical design employing 260 S4 lines tracing to 65 random S1 plants was used. The Sl-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), thickness of third-internode rind, diameter of third internode, flowering, and grain yield. Additive genetic variance was significant for all traits, whereas additive ✕ additive variances were not significant. Heritability estimates, using S1 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 (−0.31 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 appear to be somewhat unrelated to those conferring resistance to pre-frost stalk lodging. 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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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