Isolation and characterization of gamma rays induced mutants for improved agro-morphological performance and harder grain texture in wheat (Triticum aestivum L.).

Purpose: Kernel texture plays a principal role in determining technological flour properties and end-use quality of wheat products. Hence, a multi-year mutation induction programme was conducted to isolate advanced wheat mutant lines with agro-morphologically superior performance, higher disease resistance and harder grain texture.

Materials and methods: Radiation mutagenesis was employed in soft textured wheat variety HPW 89 using gamma rays dose of 250, 300 and 350 Gy (Co⁶⁰: BARC, Mumbai) and evaluated across M_1-5 generations. Promising superior mutants selected were evaluated during M₄ and M₅ generation for induced variability and trait association for agro-morphological and quality traits. The screened mutants were also determined for induced changes at genetic level using gene specific markers for puroindoline genes.

Results: A total of 293 agro-morphologically superior mutants isolated showed significant genetic variation in the M₄ generation. Single kernel characterization system categorized 267 mutants (8.79-50.06) with higher grain hardness than the HPW 89 variety (7.39). Among these, 108 mutants were selected for agro-morphological and molecular characterization. Significant variations were found in these mutants in either pina and pinb or both puroindoline genes. Clustering among these mutants led to the formation of five clusters and a total of eleven mutants were found with better set of agro-morphological, disease resistance and quality traits.

Conclusion: These mutants can serve as important genetic resource for developing harder texture bread wheat varieties in the future grain quality improvement programmes. These mutants will also bridge the need of bakers and millers' requirement of varieties with specific texture and quality.