DNA markers improved the productivity and accuracy of classical plant breeding by means of marker-assisted selection (MAS). The enormous number of quantitative trait loci (QTLs) mapping read for different plant species have given a plenitude of molecular marker-gene associations. In this review, we have discussed the positive aspects of molecular marker-assisted selection and its precise applications in plant breeding programmes. Molecular marker-assisted selection has considerably shortened the time for new crop varieties to be brought to the market. To explore the information about DNA markers, many reviews have been published in the last few decades; all these reviews were intended by plant breeders to obtain information on molecular genetics. In this review, we intended to be a synopsis of recent developments of DNA markers and their application in plant breeding programmes and devoted to early breeders with little or no knowledge about the DNA markers. The progress made in molecular plant breeding, plant genetics, genomics selection, and editing of genome contributed to the comprehensive understanding of DNA markers and provides several proofs on the genetic diversity available in crop plants and greatly complemented plant breeding devices. MAS has revolutionized the process of plant breeding with acceleration and accuracy, which is continuously empowering plant breeders around the world.

With the inevitable risk posed by global climate change to crop yield and ever increasing demands of agricultural production, crop improvement techniques have to be more precise in developing smart crop varieties. This review reviews the past, current progress and assesses the future directions in mutation breeding for crop improvement. It provides a background to plant mutation breeding strategies, basic and advanced techniques, and provides a critical review of this approach in comparison to other methods for the genetic improvement of crops. Mutation breeding is a fundamental and highly successful tool in the global efforts of agriculture to feed an ever increasing and nutritionally demanding human population. The physical and chemical mutagens, their effects and their utility are discussed. The induction of mutations has been used to enhance the yield, better nutritional quality and wider adaptability of world’s most important crops such as wheat, rice, pulses, millets and oilseeds. The total area covered by commercially released mutant cultivars clearly indicates that they have played a significant role in solving food and nutritional security problems in many countries. Of all the mutant varieties developed, majority of mutants were produced through direct mutagenesis of the plant propagules, and also there are several reports of mutants derived by irradiating rooted stem cuttings, which paves the way for in vitro mutagenesis. The production of mutants by irradiation of in vitro cultured tissues provides a means to treat large populations which would not have been possible before. The accessibility of genomics information in the public domain combined with the recent advances in molecular biology techniques have paved the way for transforming old mutation techniques into the state of art technology for crop improvement and basic genomic research. The molecular tagging and molecular marker based identification shall bring new dimensions in gene technology. These would finally lead to rapid enhancement of crops with improved yield, increased biotic and abiotic stress and reduced agronomic inputs. Thus mutation assisted plant breeding will play a crucial role in the generation of designer crop varieties to address the threats of global climate change and challenges of world food insecurity.

Cowpea, Vigna unguiculata (L.) Walp. is an important grain legume grown in the dry agro-ecologies of the tropics with considerably low yield due to lack of improved varieties, aggravated by prevalent narrow genetic base. Thus, induced mutagenesis was employed using sodium azide and gamma rays to increase genetic variability in cowpea genotypes that resulted in isolation of eleven high yielding mutant lines at the M₄ generation from the genetic background of cowpea varieties Gomati VU-89 and Pusa-578. In order to analyze the induced genetic divergence among the mutant lines and parent genotypes, biochemical and molecular characterization was carried out with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), simple sequence repeat (SSR) and CAAT box derived polymorphism (CBDP) markers. Activity of nitrate reductase (NR) and content of chlorophyll, carotenoid, protein and mineral were found to be significantly high in the selected mutant lines compared to their respective parent genotypes. SDS-PAGE profile of seed proteins generated 54 and 28 polymorphic bands and a total polymorphism of 62.06 and 41.17% in Gomati VU-89 and Pusa-578, respectively. SSR primers amplified a total of 16 and 24 polymorphic bands with an average polymorphism of 20.69 and 50.74% in Gomati VU-89 and Pusa-578, respectively. CBDP markers, used for the first time in mutagenized population, generated 175 bands with 77 bands being polymorphic in Gomati VU-89 and 121 bands with 59 bands being polymorphic in Pusa-578. Physiological, biochemical and molecular profiling of the selected promising mutants lines showed that Gomati VU-89-G and Pusa-578-C are genetically most diverged high yielding genotypes with significant increase in protein and micronutrient content, therefore, could be recommended for further research considerations. Thus, the favorable combination of genes induced in the novel cowpea mutants selected through the present study are valuable to correspond farmers requirements for new improved cultivars (direct or hybrids).

Faba bean is one of the most important grain legumes in the world because of its multiple uses and its ability to grow over a wide range of climatic conditions. The objective of this study was to evaluate the effectiveness and efficiency of single and combination doses of gamma rays and ethyl methanesulphonate (EMS) on two different varieties of faba bean. Studies on induced mutagenesis in faba bean involving EMS and gamma rays are sparse. Genetically pure, uniform, dry and dormant seeds of Vicia faba varieties Vikrant and PRT-12 were treated with four different doses of gamma rays (100, 200, 300 and 400 Gy) and of EMS (0.01, 0.02, 0.03 and 0.04%). However, the utility of a mutagenic agent is determined by its ability to induce a high frequency of desirable mutations as compared to undesirable ones; thus, it is necessary to assess the effectiveness and efficacy of mutagens. The results indicated that EMS is more effective in inducing mutations than gamma rays, with the following trend: EMS > gamma rays+EMS > gamma rays. However, with regard to mutagenic efficiency measured based on seedling injury, gamma rays were more efficient than EMS, with the following trend: gamma rays > gamma rays+EMS > EMS. Both mutagenic effectiveness and efficiency were found to be higher at lower doses of both the mutagens. The possible reason for decrease in mutagenic efficiency and effectiveness with increase in dose may be the higher dose of mutagens and less damaging effect of lower doses of mutagens.