Agronomy and Horticulture Department


Date of this Version



Published in Crop Science (January-February 1986) 26: 65-67.


Seedlings of both KS8 and N32 sorghum [Sorghum bicolor (L.) Moench] were high in dhurrin [p-hydroxy-(S)-mandelonitrile-β-D-glucoside] and thus in hydrocyanic acid potential (HCN-p), but the HCN-p of mature leaves from field-grown plants of KS8 was only about one-tenth as high as that of N32. A study of the inheritance of this large difference between KS8 and N32 revealed that a single major gene pair was responsible. There were no obvious maternal effects and F,'s were generally intermediate in HCN-p level between the two parents, indicating that neither high nor low HCN-p was completely dominant. HCN-p level was influenced by genetic background since mean values of the low and intermediate HCN-p classes increased slightly as the proportion of genetic background ascribable to N32 was increased. A survey of 102 additional sorghums revealed that the gene for low HCN-p carried by KS8 does not appear to occur widely because KS8 had the lowest HCN-p of all entries assayed.