Heterosis and Combining Ability in a Diallel Cross of Ethiopian Mustard Inbred Lines

Abstract

Heterosis is commercially exploited in rapeseed ( Brassica napus L.) and its potential use has been demonstrated in turnip rape ( B. rapa L.) and Indian mustard ( B. juncea L.). In Ethiopian mustard ( B. carinata A. Braun), however, information regarding heterosis has not been previously reported. This study, therefore, was conducted to generate information on heterosis and combining ability in B. carinata Nine inbred parents and their 36 F 1 s, obtained by half‐diallel cross, were evaluated for 12 traits at three locations in Ethiopia. Analysis of variance showed the presence of significant heterosis for all the traits. Seed yield showed the highest relative mid‐parent heterosis that varied from 25 to 145% with a mean of 67%. Relative high‐parent heterosis for seed yield varied from 16 to 124% with a mean of 53%. General combining ability (GCA) effects were predominant in all traits except secondary branches and pods per plant. Specific combining ability (SCA) was significant for days to flowering, secondary branches, pods per plant, pod length, seeds per pod, 1000‐seed weight and oil content. Interaction effects of GCA × location were significant for all traits except days to flowering, days to maturity, and oil content. All traits had significant SCA × location interaction effects. GCA effect for seed yield was positively correlated with F 1 performance ( r = 0.77) and absolute mid‐parent heterosis ( r = 0.67). The presence of high levels of mid‐ and high‐parent heterosis indicates a considerable potential to embark on breeding of hybrid or synthetic cultivars in Ethiopian mustard.