Association analysis of molecular markers with various agronomic traits of horsegram (Macrotyloma uniflorum)
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Date
2021-11-30
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Palampur
Abstract
Macrotyloma uniflorum is an important, self pollinated diploid (2n=2x=20) food legume with
probable genome size of 400Mbps. Limited genomic resources and lack of genetic variation
are major constrains in its genetic improvement. Further, horsegram production is hampered
due to twining growth habit, longer days to maturity, photosensitivity and indeterminate
growth habit. The present study was aimed with the objective(s) to estimate genetic diversity
among a diverse panel of horsegram accessions and to analyze the association of molecular
markers with various agronomic traits. To dissect the association of molecular markers with
various agronomic traits in horsegram and identification of genomic regions linked to
morphological, phenological, biochemical and yield related traits 88 diverse horsegram
germplasm lines were evaluated for various agronomic traits for four years at two locations.
Lines were analysed using 791 SNPs and 37 SSRs polymorphic markers. Of these 704 SNPs
and 37 SSR were mapped with known chromosomal location and were found to be
significantly associated with traits of interest.
Analysis of variance of germplasm population revealed significant differences for all the
measured traits except days to maturity. Phenotypic and genotypic data were used to identify
QTLs for various agronomic traits by using compressed Linear model (CMLM), Generalized
linear model (GMLM) and Mixed linear model (MLM). A total of 146 QTLs were detected
across the five environments for 12 agronomic traits. Among these, 25 were major and stable
QTLs across locations and years with heritability more than 80 percent.
In conclusion, it is envisaged that the present association study fortified with 704 SNP
markers, 37 SSR markers and 25 QTLs for various agronomic traits, which would provide
genomics tools to breeders for further genetic enhancement of this crop species. Thus, the
current study will serve as a strong foundation for further validation and fine mapping of
QTLs for utilization in horsegram breeding programs.