Germplasm should be conserved in such a way that the genetic integrity of a given accession is maintained. In most genebanks, landraces constitute a major portion of collections, wherein the extent of genetic diversity within and among landraces of crops vary depending on the extent of outcrossing and selection intensity infused by farmers. In this study, we assessed the level of diversity within and among 108 diverse landraces and wild accessions using both phenotypic and genotypic characterization. This included 36 accessions in each of sorghum, pearl millet, and pigeonpea, conserved at ICRISAT genebank. We genotyped about 15 to 25 individuals within each accession, totaling 1,980 individuals using the DArTSeq approach. This resulted in 45,249, 19,052, and 8,211 high-quality single nucleotide polymorphisms (SNPs) in pearl millet, sorghum, and pigeonpea, respectively. Sorghum had the lowest average phenotypic (0.090) and genotypic (0.135) within accession distances, while pearl millet had the highest average phenotypic (0.227) and genotypic (0.245) distances. Pigeonpea had an average of 0.203 phenotypic and 0.168 genotypic within accession distances. Analysis of molecular variance also confirms the lowest variability within accessions of sorghum (26.3%) and the highest of 80.2% in pearl millet, while an intermediate in pigeonpea (57.0%). The effective sample size required to capture maximum variability and to retain rare alleles while regeneration ranged from 47 to 101 for sorghum, 155 to 203 for pearl millet, and 77 to 89 for pigeonpea accessions. This study will support genebank curators, in understanding the dynamics of population within and among accessions, in devising appropriate germplasm conservation strategies, and aid in their utilization for crop improvement.

Little millet (Panicum sumatrense Roth. Ex. Roem. & Schult.), a member of the grass family Poaceae, is native to India. It is nutritionally superior to major cereals, grows well on marginal lands, and can withstand drought and waterlogging conditions. Two-hundred diverse little millet landraces were characterized to assess variability for agronomic and nutritional traits and identify promising accessions. Highly significant variability was found for all the agronomic and grain nutrient traits. Accessions of robusta were high yielding whereas those of nana were rich in grain nutrients. About 80% of the accessions showed consistent protein and zinc (Zn) contents whereas iron (Fe) and calcium (Ca) contents were less consistent (29.5 and 63.5%, respectively) over 2 yr. Promising trait-specific accessions were identified for greater seed weight (10 accessions), high grain yield (15), high biomass yield (15), and consistently high grain nutrients (30) over 2 yr (R 2 = .69-.74, P ≤ .0001). A few accessions showed consistently high for two or more nutrients (IPmr 449 for Fe, Zn, Ca, and protein; IPmr 981 for Zn and protein). Five accessions (IPmr 855, 974, 877, 897, 767) were high yielding and also rich in Ca. Consumption of 100 g of little millet grains can potentially contribute to the recommended dietary allowance of up to 28% Fe, 37% Zn, and 27% protein. Multilocation evaluation of the promising accessions across different soil types, fertility levels, and climatic conditions would help to identify valuable accessions for direct release as a cultivar or use in little millet improvement. INTRODUCTIONCrop and dietary diversity by including climate-resilient and nutrient-rich underutilized crops can potentially con-Abbreviations: DAS, days after sowing; DV, daily value; RDA, recommended daily allowance per 100 g; SNP, single nucleotide polymorphism.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Finger millet [Eleusine coracana (L.) Gaertn.] is an important climate-resilient nutrient-dense crop grown as a staple food grain in Asia and Africa. Utilizing the full potential of the crop mainly depends on an in-depth exploration of the vast diversity in its germplasm. In this study, the global finger millet germplasm diversity panel of 314 accessions was genotyped, using the DArTseq approach to assess genetic diversity and population structure. We obtained 33,884 high-quality single nucleotide polymorphism (SNP) markers on 306 accessions after filtering. Finger millet germplasm showed considerable genetic diversity, and the mean polymorphic information content, gene diversity, and Shannon Index were 0.110, 0.114, and 0.194, respectively. The average genetic distance of the entire set was 0.301 (range 0.040 – 0.450). The accessions of the race elongata (0.326) showed the highest average genetic distance, and the least was in the race plana (0.275); and higher genetic divergence was observed between elongata and vulgaris (0.320), while the least was between compacta and plana (0.281). An average, landrace accessions had higher gene diversity (0.144) and genetic distance (0.299) than the breeding lines (0.117 and 0.267, respectively). A similar average gene diversity was observed in the accessions of Asia (0.132) and Africa (0.129), but Asia had slightly higher genetic distance (0.286) than African accessions (0.276), and the distance between these two regions was 0.327. This was also confirmed by a model-based STRUCTURE analysis, genetic distance-based clustering, and principal coordinate analysis, which revealed two major populations representing Asia and Africa. Analysis of molecular variance suggests that the significant population differentiation was mainly due to within individuals between regions or between populations while races had a negligible impact on population structure. Finger millet diversity is structured based on a geographical region of origin, while the racial structure made negligible contribution to population structure. The information generated from this study can provide greater insights into the population structure and genetic diversity within and among regions and races, and an understanding of genomic-assisted finger millet improvement.

Landraces are highly dynamic populations with historical origins. Several factors have influenced the evolution of landraces and some of them were selection by farmers, natural selection, gene-flow from various neighboring populations, genetic drifts, etc. In this study, we phenotyped 36 landraces and wild populations of sorghum conserved at ICRISAT genebank, Hyderabad, India, to assess the diversity among the populations of sorghum. Since landraces are diverse populations, we phenotyped more plants (over 100 plants) in each accession for nine economically important quantitative traits, thus capturing the entire variability. Our study revealed that the clustering pattern based on D 2 statistics grouped the 36 accessions into 5 clusters, in which cluster 1 holds the maximum number of 15 accessions and cluster 3 with the least (2 accessions). Minimal intra cluster distance (3.66) was observed in cluster 3 followed by cluster 5 (9.52), while the maximum intra cluster distance was found in cluster 2 (12.50). The highest inter cluster distance was found between clusters 1 and 4 (16.29) indicating the presence of wide diversity between accessions of these two clusters. Accessions in cluster 1 were early maturing (67 days after sowing, DAS) while those in cluster 4 were late maturing (129 DAS) and high yielding (36.9 g). Results from this study provide information about the diversity of landraces and wild sorghum populations for their utilization in crop improvement

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