Heterosis and combining ability are reputable fundamental breeding tools in assessing the performance of hybrids and the extent of the parents’ combining ability. In the present study, evaluating 11 yield-attributing traits of 15 hybrids of the field mustard (Brassica rapa L.) helped estimate the magnitude and direction of combining ability and heterotic effects. The hybrids evolved from six diverse parents following a half-diallel mating scheme at the research farm of Sher-e-Bangla Agricultural University. The GCA effects showed that parents BARI-12, BARI-17, and BINA-10 for early maturity and plant height, while the parents BARI-6, BARI-14, and Maghi can be favorable as potential parents for yield-attributing traits. The hybrids BARI-6 × BARI-12 and BARI-12 × BINA-10 exhibited maximum negative SCA and heterotic effects for early maturity, and the hybrids BARI-12 × BARI-17 and BARI-14 × Maghi had the highest negative effects for plant height. Moreover, for yield and yield-contributing traits, hybrids BARI-6 × BARI-14, BARI-14 × Maghi, and BARI-17 × Maghi manifested higher SCA and heterotic effects than the other hybrids. The phylogeny and clustering analysis showed the developed hybrids have quite diversity, having been positioned in different clades. It suggests breeding superior recombinants could be effective from the segregating populations of hybrids.

Keywords: Mustard (B. rapa L.), combining ability, heterosis, genetic distance, early maturity, highyielding hybrids

Key findings: Promising findings indicate the early maturity and short-stature phenotypes incurred controlled by additive genetic effects. In general, non-additive gene action regulates the inheritance of most of the yield-attributing traits in B. rapa L. Overall, the hybrids, viz., BARI-6 × BARI-14, BARI-12 × BARI-17, and BARI-17 × Maghi could become potential lines in B. rapa L. breeding programs.