Statistical Characterization and Trait Association Studies for Selection of Elite Mutant Lines of Mustard (Brassica juncea L.)

Abstract

The​‍​‌‍​‍‌​‍​‌‍​‍‌ study presented to assess the scope of genetic variability and the interrelationships among different traits of the mutant lines of mustard (Brassica juncea L.) after treatment of the variety PM 21 with sodium azide mutagenesis. Seventy-one M4 generation mutant lines were evaluated in the field for nine agronomic and yield-related traits. The genotypes differed significantly for all the traits, indicating vast genetic diversity. The range of days to 50% flowering was 44.00 to 58.50 days (mean = 50.22 ± 3.07, CV = 6.1%), and days to maturity ranged from 88.00 to 107.00 days (mean = 100.37 ± 5.92, CV = 5.9%), indicating moderate variability. Plant height varied greatly from 124.90 to 223.77 cm (mean = 172.44 ± 16.66, CV = 9.7%), while the number of seeds per plant showed the highest variability (74.27 to 381.50; mean = 194.92 ± 65.11, CV = 33.4%), thus revealing a wide genetic base. The seed yield per plant ranged from 3.96 to 16.64 g (mean = 9.25 ± 2.76, CV = 29.8%), thus indicating high genetic variability for yield potential. Correlation analysis showed that days to 50% flowering had a positive correlation with days to maturity (r = 0.157 and a negative correlation with the number of seeds per plant (r = –0.163). Also, plant height was strongly positively correlated with the number of siliqua per plant (r = 0.44) and seed yield per plant (r = 0.181). The number of siliquae per plant showed the strongest positive correlation with seed yield (r = 0.34), identifying it as a main yield-determining factor. The findings of this study emphasize the presence of considerable genetic variability and the importance of choosing genotypes with a high number of siliqua and moderate plant height to enhance mustard yield ​‍​‌‍​‍‌​‍​‌‍​‍‌potential.