Estimating combining ability of advanced rapeseed lines for seed yield and yield components

Abstract

To estimate heritability and combining ability for yield components, seed yield, and related traits, a one-way diallel cross
involving eight canola lines (G41, Zafar, G56, G31, G22, GF2, G204, and G104) and their parents was evaluated in a
randomized complete block design with three replications. Diallel analysis revealed that the mean square for general
combining ability (GCA) was significant for all traits, whereas specific combining ability (SCA) was significant for all
traits except 1000-seed weight. Furthermore, the relatively high estimates of narrow-sense heritability for pod length
(0.50), 1000-seed weight (0.69), seed yield (0.63), and harvest index (0.53) suggest that additive gene effects play a
predominant role in the genetic control of these traits. The parental lines G41, Zafar, and G22 exhibited positive and
significant GCA effects for seed yield and were identified as superior combiners. Moreover, hybrids with positive and
significant SCA effects for seed yield generally included at least one parent with significant positive GCA for this trait.
Among the evaluated hybrids, G41 × G22, G41 × GF2, Zafar × G22, and Zafar × G204 were identified as the most promising
combinations, producing seed yields of 3422, 3400, 3348, and 3311 kg ha-¹, respectively.