RESUMEN
PURPOSE: Mungbean yellow mosaic India virus (MYMIV) is a serious constraint in the mungbean which is a potential source of easily digestible high-quality proteins, fibers, minerals, and vitamins in Asian countries. Developing resistant cultivars is the most cost-effective, eco-friendly, and sustainable approach to protect mungbean from MYMIV damage. Mutation breeding provides a quick and cost-effective way of developing resistance as lack of genetic variability is the biggest bottleneck for other traditional breeding tools. MATERIALS AND METHODS: Outstanding but MYMIV-sensitive varieties of mungbean, viz., MH 2-15 and MH 318 were mutagenized through various individual and combined doses of gamma-rays and Ethyl methanesulfonate (EMS) and evaluated in M2 and M3 generations for the appearance of resistance reactions. This was subsequently validated through marker-assisted genotyping using previously reported Yellow Mosaic Disease (YMD) linked markers. RESULTS: The phenotyping in M3 generation yielded 64 MYMIV resistant mutants whereas, marker-assisted genotyping identified the 22 mutants with true resistance. Markers YR4, CYR1, and CEDG180 were found associated with MYMIV resistance whereas, DMB-SSR158 did not show any amplification. Among identified resistant mutants, ten lines exhibited at par and two revealed a little higher seed yield over controls. CONCLUSIONS: The mutagenesis created significant variability in MYMIV resistance as well as seed yield per plant. YR4, CYR1, and CEDG180 are found to be linked with the MYMIV loci in the mungbean and could be utilized for MYMIV resistance breeding. Mutant M-37 from MH 2-15 and M-104 from MH 318 exhibited more seed yield along with MYMIV resistance which upon further validation can be released as a variety. The induced mutagenesis integrated with powerful emerging molecular and next-generation sequencing (NGS) tools would be highly helpful in breeding mungbean for durable resistance against threatening MYMIV.
Asunto(s)
Begomovirus , Vigna , Metanosulfonato de Etilo , Enfermedades de las Plantas/genética , Vigna/genéticaRESUMEN
Mung bean [Vigna radiata (L.) Wilczek] is an important short-duration grain legume widely known for its nutritional, soil ameliorative, and cropping system intensification properties. This study aims at evaluating genetic diversity among mung bean genotypes and detecting genomic regions associated with various yield attributing traits and yellow mosaic disease (YMD) resistance by association mapping. A panel of 80 cultivars and advanced breeding lines was evaluated for 10 yield-related and YMD resistance traits during kharif (monsoon) and summer seasons of 2018-2019 and 2019-2020. A total of 164 genome-wide simple sequence repeat (SSR) markers were initially screened, out of which 89 were found polymorphic which generated 317 polymorphic alleles with an average of 3.56 alleles per SSR locus. The number of alleles at each locus varied from 2 to 7. The population genetic structure analysis grouped different genotypes in three major clusters and three genetically distinct subpopulations (SPs) (i.e., SP-1, SP-2, and SP-3) with one admixture subpopulation (SP-4). Both cluster and population genetic structure analysis categorized the advanced mung bean genotypes in a single group/SP and the released varieties in other groups/SPs, suggesting that the studied genotypes may have common ancestral history at some level. The population genetic structure was also in agreement with the genetic diversity analysis. The estimate of the average degree of linkage disequilibrium (LD) present at the genome level in 80 mung bean genotypes unveiled significant LD blocks. Over the four seasons, 10 marker-trait associations were observed significant for YMD and four seed yield (SY)-related traits viz., days to flowering, days to maturity, plant height, and number of pods per plant using the mixed linear model (MLM) method. These associations may be useful for marker-assisted mung bean yield improvement programs and YMD resistance.