Agromorphological and Physiological Trait Diversity in Ethiopian Mustard (Brassica carinata A. Braun) Germplasm

Abstract

Ethiopian mustard (Brassica carinata A. Braun) is a versatile oil crop cultivated for vegetable and oilseed production. Despite the availability of numerous landraces, a comprehensive understanding of their phenotypic diversity remains limited, hindering breeding efforts to improve the crop. This study evaluated 386 Ethiopian mustard accessions for 21 agromorphological and six physiological traits over two growing seasons using an augmented block design. This comprehensive analysis aimed to uncover the extent of phenotypic variation within the germplasm collection and identify promising genotypes with desirable traits for breeding. Significant variation (p≤0.001) was found among accessions, highlighting their substantial phenotypic diversity. Principal component analysis (PCA) revealed that the top 5 components explained 61.23% of the total variation, providing insights into the major contributors to phenotypic variability. Cluster analysis grouped the accessions into four distinct clusters, with the highest intercluster divergence (18.21) observed between clusters 3 and 4. This suggests the potential for selecting diverse genotypes across phenotypic groups, which could be valuable for broadening the genetic base of breeding programs. Cluster 2 exhibited the highest intracluster distance (6.71) and mean genetic distance (5.23), implying extensive agromorphological and physiological variability, valuable for breeding to develop cultivars with diverse traits. Overall, this study identified several superior performing genotypes: acc-192, acc-386, acc-1, acc-192, acc-377, acc-1, acc-235, acc-294, acc-302, acc-112, acc-331, acc-152, acc-55, and acc-72 characterized by high seed yields and oil content. These accessions are promising candidates for further improvement and incorporation into breeding programs. These findings reveal extensive genetic diversity in Ethiopian mustard and provide valuable insights for future breeding programs, highlighting the potential of conserving genetic resources to enhance the crop’s performance, adaptability, and versatility, ultimately supporting sustainable agriculture and alternative energy development initiatives.