Identification of new alleles resistant to moisture stress in mutant lines of wheat genotypes developed by chemical mutagenesis through drought-specific ISSR markers

Abstract

Water stress is a significant global issue that severely limits crop production worldwide, and recent changes in the global climate have exacerbated the problem. Wheat crops are especially vulnerable to water shortages, which result in decreased yield and production. Mutation breeding offers a potential alternative approach for developing crops that are important for agriculture. It can enhance specific traits without altering entire genotype. In this study, ISSR markers were employed to evaluate genetic variation and diversity at the molecular level among selected M₃ mutant lines and wild-type wheat genotypes after chemical mutagenesis in response to moisture stress during 2022–2023 rabi season at SVPUA&T, Meerut, India. Out of 15 ISSR primers, 12 showed successful amplification across both genotypes. In HD-3226, 50 alleles and 585 amplified bands were recorded across 13 ISSR loci. PIC values ranged from 0.21 to 0.81, with an average of 0.47 for EMS and 0.39 for SA. The resolving power ranged between 2.33 and 9.56, while the marker index ranged from 0.59 to 3.95. Nine primers exhibited 100% polymorphism, and genetic similarity ranged from 0.40 to 0.88. UPGMA clustering grouped mutant lines into five clusters with genetic distances ranges from 0.54 to 1.00. The greatest dissimilarity (0.404) was observed between mutant 0.5% EMS (15% PEG, P-41) and 0.75% EMS (15% PEG, P-63) whereas the highest similarity (0.880) was between 0.04% SA (15% PEG, P-36) and 0.25% EMS (15% PEG, P-19). In HI-1620, 41 alleles and 273 amplified bands were produced. PIC values ranged from 0.00 to 0.89, with averages of 0.35 (EMS) and 0.42 (SA). Resolving power varied from 1.40 to 7.00, and marker index from 0.30 to 2.75. Eight primers showed 100% polymorphism. Genetic similarity ranged from 0.411 to 0.823. UPGMA dendrogram formed four clusters with genetic distances between 0.50 and 0.97. M₃ mutant lines 0.02% SA (15% PEG, P-28) and 0.25% EMS (15% PEG, P-4) were found to closely dissimilar (0.411) to each other while highest genetic similarity (0.823) was detected between mutant lines 0.02% SA (15% PEG, P-4) and 0.25% EMS (15% PEG, P-4). Our study found that ISSR markers, with their high PIC and resolving power, are highly effective at distinguishing closely related wheat mutant lines. Furthermore, identified M₃ mutants represent promising resources for reverse genetics and functional genomics approaches to improve drought tolerance in wheat.