Identification of QTLs linked to early maturity and yield related traits in horsegram Macrotyloma uniflorum

Abstract

newline Macrotyloma uniflorum is an important, self pollinated diploid (2n=2x=20) food newlinelegume with probable genome size of 400Mbps. Limited genomic resources and lack of newlinegenetic variation are major constrains in its genetic improvement. Further, horsegram newlineproduction is hampered due to twining growth habit, longer days to maturity, photosensitivity newlineand indeterminate growth habit. The present study was aimed to construct linkage map of an newlineintraspecific F8 RILs population of 162 individuals derived from HPKM249×HPK4 of newlinehorsegram and identification of genomic regions linked to early maturity and yield related newlinetraits. Two thousand and eleven molecular markers were screened for parental polymorphism newlineand 493 (25.42 %) were found to be polymorphic among the parents. Of these, 295 were newlinemapped on ten linkage groups at LOD 3.5 spanning 1541.7 cM with an average marker newlinedensity of 5.20 cM. newlineAnalysis of variance of 162 RILs revealed significant differences for all the measured newlinetraits. Phenotypic data from the RILs were used to identify QTLs for early maturity and yield newlinerelated traits by composite interval mapping (CIM). A total of 27 QTLs (LOD and#8805; 2.5) were newlinedetected across the three environments (Palampur 2016, Palampur 2017, Bajaura 2017) and newlinecombined data) for 24 traits. Among these, 15 were major QTLs with PVE greater than ten newlineper cent and five were stable QTLs across locations and years. Phenotypic variation explained newline(PVE) by QTLs ranged from 6.4 to 53.4 per cent. The highest phenotypic variation (53.4 %) newlinewas explained by the QTLs for root length. newlineIn conclusion, it is envisaged that the present linkage map, fortified with 295 SSR newlinemarkers and 27 QTLs for early maturity and yield-related traits would provide genomics tools newlineto breeders for further genetic enhancement of this crop species. Thus, the current study will newlineserve as a strong foundation for further validation and fine mapping of QTLs for utilization in newlinehorsegram breeding programs.