Independent Inheritance of Genes for Dhurrin and Leucoanthocyanidin in a Sorghum Cross
- F. A. Haskins * and
- H. J. Gorz
Flag leaves of KS8 sorghum [Sorghum bicolor (L.) Moench] are low in dhurrin [p-hydroxy-(S)-mandelonitrile-β-D-glucoside] content and thus in hydrocyanic acid potential (HCN-p), and they contain little (if any) leucoanthocyanidin (LAC). Comparable leaves ‘Colman’ sorghum are intermediate in HCN-p and high in LAC. This study was conducted to investigate the inheritance of HCN-p and LAC in crosses of KS8 ✕ Colman. Flag leaves from field-grown plants of both parents; the F1, KS8 ✕ Colman; the backcross, KS8 ✕ (KS8 ✕ Colman); and the F2, (KS8 ✕ Colman) selfed, were assayed for both HCN-p and LAC. Assays for HCN-p indicated that the backcross values provided a good fit to 1 intermediate:1 low (X2 = 0.05, P = 0.82) and F2 results to 3 intermediate:1 low (X2 = 0.96, P = 0.33). For LAC, backcross results were 1 LAC+:1 LAC− (X2 = 0.20, P = 0.65) and F2 values were 3 LAC+:1 LAC− (exact fit). Classification for both traits yielded good fits to 1:1:1:1 for the backcross (X2 = 0.30, P = 0.96) and 9:3:3:1 for the F2 (X2 = 3.24, P = 0.36). These results indicated that the difference in HCN-p between Colman and KS8 depended primarily on a single gene, the difference in LAC depended largely on a separate single gene, and the HCN-p gene and the LAC gene were not linked.
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