INHERITANCE OF GRAIN YIELD, SEED NUMBER AND SEED SIZE IN SORGHUM

Abstract

In this study the inheritance of grain yield per main panicle (GYP), grain number per main panicle (GNP), and 100-grain weight (GW) was determined in sorghum (Sorghum bicolor L.Moench), and useful lines for plant breeding were identified. An experiment with six crosses involving three females (W-A, 46038A y SJ7A) and two pollinators (17473R and 22830R) with six populations each (P₁, P₂, F₁, F₂, BCP₁, and BCP₂), was established in 1997 at Nebraska, USA, under rainfed conditions. Two more experiments were established in 1998, using the cross SJ7Ax22830R with seven populations (P₁, P₂, F₁, F₂, BCP₁F₂, BCP₂F₂ and F₃ progeny). The inheritance for GYP was predominantly of dominance, for GNP both additive and dominance gene actions were important, and for GW differed between crosses. Crosses involving the pollinator 22830R had only additive effects, while for crosses involving the pollinator 17473R the dominance effects were also important. Mid parent heterosis for GNP ranged from 13.9 to 47.7 % and for GW from –0.3 to 20.8 % in one experiment, and 52.1 and 7.6 %, respectively, for the other assay. The male line 17473R produced across females simultaneous heterosis for GNP and GW, while the line 22830R produced heterosis only for GNP. The F₃ progeny mean heritability for the cross SJ7Ax22830R was of 0.71, 0.72 and 0.83 for GYP, GNP and GW, respectively. The restorer line 17473R is important for breeding purposes because of its high GNP contribution and high heterosis for GW, and the importance of line 22830R is due to its high GW contribution and high heterosis for GNP.