Induced mutagenesis for the development of high-yielding mutant lines of linseed (Linum usitatissimum L.) using caffeine and sodium azide

Generating variability is key for enhancing crops in any plant breeding initiative. This study aimed to create mutant lines with improved yield through induced mutation. Linum usitatissimum L. (variety ‘Shekhar’) was subjected to various concentrations of caffeine and sodium azide (0.10, 0.25, 0.50, 0.75, and 1.00%) before being sown to produce the M1 generation. After harvesting and screening the M1 variants, they were planted to cultivate the M2 generation. The M2 mutants undertook a thorough morphological examination for different mutation types and were then planted to develop the M3 generation. Across the three generations, various parameters were analyzed, including quantitative traits (plant height, number of branches), morphological traits (cotyledonary, vegetative leaf, and flower mutants), physiological traits (chlorophyll and carotenoid content), cytological aspects, and yield characteristics. The results indicated that caffeine was more effective than sodium azide in generating beneficial mutants. In the M3 generation, nine high-yielding mutant lines, labelled A, B1, B2, C1, C2, D, E, F1, and F2, were selected based on their morphological and yield-related traits. Also, SEM analysis was conducted on selected high-yielding mutants to examine stomatal variations in their leaves and to assess their seed morphology. These mutant lines have considerable breeding significance and should be advanced to future generations to promote their trait stability, ultimately creating new linseed cultivars with enhanced yield and better adaptability.