Genetic characterization and divergence studies of maize (Zea maysL.) lines developed from landraces indigenous to North Eastern Hill Region (NEHR) of India

Abstract

AbstractThe current study focused on characterization of the underlying genetic divergence in inbred lines developed from local landraces of North Eastern Hill Region of India – a designated Asiatic maize diversity centre – following six generations of inbreeding. Substantial genetic differentiation was indicated based on very high to moderateFstvalues for 22 of the 38 simple sequence repeat markers studied. STRUCTURE analysis partitioned the subset into two distinct and one admixture subgroup (Populations I, II and III respectively) accompanied by a significant reduction in heterozygosity. Population II was further subdivided into subpopulations Pop-M9 and Pop-T9. Nei's pairwise genetic distance and populationFstvalues indicated that Populations I and II were more divergent with neighbour joining clustering analysis clearly defining landraces originating from the states of Tripura (Population II) and Sikkim (Population I) as most divergent. Principal coordinates analysis could explain 31.26% of the variation present in the subgroups wherein Population I was more variable. Analysis of molecular variance andFstcoefficients (P< 0.001) indicated 17% population structuring with 55% variation detected for individuals within populations. These results combined with the presence of phenotypic variability in the subgroups for yield traits supported by results of a preliminary partial diallel analysis strongly suggest the existence of distinct heterotic groups. Divergence studies are crucial for exploiting heterosis, and the current study would go a long way to help establish a germplasm base for developing varieties with improved agronomic performance and surer commercial prospects no reports of which are available thus far.