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

Abstract

The 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 moderate Fst values 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 population Fst values 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 and Fst coefficients (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.

Genetic Diversity within a Collection of Italian Maize Inbred Lines: A Resource for Maize Genomics and Breeding

“…As an example, in recent studies, values of genetic variance between groups varying from 3% [38] to 17% [39] were reported. Based on Nei's genetic diversity, a reduction was observed in Group 4, containing many modern lines, compared to groups characterized by inbred lines derived from traditional landraces.…”

Harnessing potential of maize (Zea mays) genetic resources for exploring yield and yield-related traits under organic farming in hill region

“…These represent collections from farmers’ field located at different locations of Eastern and NEH region which are highly heterogeneous due to their breeding behaviour and population mixtures commonly observed in cross-pollinated crops. LR from NEH region have shown high phenotypic variability for leaf length, width, ear length, ear width, kernel rows per cob, kernels per row and test weight (Goyanka et al ., 2021) and divergence in inbred lines developed from local populations for exploiting heterosis (Naveenkumar et al ., 2020). Plant height, ear height, grain yield, ear width, number of kernel rows and kernels per row were major contributors to phenotypic diversity of maize LR (Kumar et al ., 2015; Kumari et al ., 2016).…”