Prediction of heterotic combinations using correlation between genetic distance, heterosis and combining ability in yellow sarson ( Brassica rapa var. yellow sarson Prain)

Prediction of heterotic combinations from parental dissimilarity will improve the efficiency of heterosis breeding. This study was conducted to determine genetic divergence among 15 local germplasm lines of yellow sarson using 11 morphological traits and to study the correlation between parental genetic distance, combining ability and heterosis for the prediction of better heterotic combination. The 15 germplasm lines, 44 F 1 s (11 lines × 4 tester) along with check variety Pant Shweta were evaluated at Pantnagar, India. The principal component analysis revealed seven significant principal components accounting for 99.99% of the total variation. The Euclidean dissimilarity values ranged from 1.912 to 8.087 and genotypes were grouped into three clusters. Relationships between a group of five dissimilarity coefficients (usual Euclidean, mean Euclidean, Manhattan, range Manhattan and exponential range Manhattan) with heterosis, sum of parental combining ability (SGCA) and specific combining ability (SCA) were calculated using Pearson correlation coefficient. Standard heterosis for plant height and mid-parent heterosis for oil content and number of seed per silique have positive correlation with all dissimilarity coefficients. SGCA exhibited a positive correlation for plant height and silique density, while SCA did not associate significantly for any of the traits studied. Further, the correlation between combining ability and heterosis was also studied and strong significant correlation between combing ability and heterosis was observed for most of the traits studied. Owing to the strong correlation between SGCA and heterosis for most yield attributing trait, information of SGCA to predict heterosis appears to be a better method in Brassica rapa var. yellow sarson.