Evaluation of genetic diversity and selection of superior mutant lines in rapeseed (Brassica napus L.): the impact of mutations on yield and agronomic traits

Genetic variability is an indispensable prerequisite for any plant breeding program. The emergence of potential genetic capabilities that do not occur naturally is made possible by the induction of mutations using physical mutagens, which create genetic diversity. The objective of this project was to create genetic diversity in rapeseed through the use of gamma irradiation and to select superior mutant lines for the introduction of improved cultivars. The mutant population was evaluated during M2–M4, and 32 superior mutants were selected based on yield and morphological traits. The 32 mutant lines of rapeseed in the M5 and M6 generations were evaluated throughout, for two crop seasons. The results demonstrated that the number of seeds per pod, thousand seed weight, number of pods per plant, and grain yield per plant of the superior mutants, including RG16, RG14, RG31, and RG9, were significantly higher than those of the other mutants and their parents. The biplot analysis indicated a high degree of genetic diversity concerning to grain yield, number of pods per plant, and plant height. Our results suggest pods per plant and thousand seed weight represent the two primary selection criteria for high-yielding mutants. Furthermore, RG16, RG14, RG30, and RG9 exhibited stability in yield and were identified as promising mutant lines.