Genetics of post-flowering drought tolerance traits in post-rainy sorghum [Sorghum bicolor (L.) Moench]

Abstract

Post-rainy sorghum (Sorghum bicolor L. Moench) is mostly cultivated under receding soil moisture leading to postflowering moisture stress. Gene effects governing six moisture stress tolerance attributing traits were studied in nine generations of a cross between drought susceptible parent, SPV 1587 and drought tolerant parent, Phule Maulee under natural receding soil moisture regime during winter season of 2006-07 under randomized block design with three replications. Phule Maulee recorded higher relative leaf water content, chlorophyll stability index and grain yield per plant. Stomata frequencies were less on both surfaces in the drought tolerant parent. Heterosis and preponderance of duplicate epistasis (particularly dominance × dominance) were recorded for all the traits. This suggested the potential for hybrid breeding for drought tolerance in sorghum. Transgressive segregants were recorded for all the traits. Presence of significant dominance x dominance epistatic interactions suggests that selection for drought tolerance should be avoided in early generations and practiced in the advanced generations.