Independent Inheritance of Genes for Dhurrin and Leucoanthocyanidin in a Sorghum Cross

Publisher Website
Google Scholar
Abstract
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.