The studies on genetic variation, diversity and population structure of rice germplasm of North East India could be an important step for improvements of abiotic and biotic stress tolerance in rice. Genetic diversity and genetic relatedness among 114 rice genotypes of North East India were assessed using genotypic data of 65 SSR markers and phenotypic data. The phenotypic diversity analysis showed the considerable variation across genotypes for root, shoot and drought tolerance traits. The principal component analysis (PCA) revealed the fresh shoot weight, root volume, dry shoot weight, fresh root weight and drought score as a major contributor to diversity. Genotyping of 114 rice genotypes using 65 SSR markers detected 147 alleles with the average polymorphic information content (PIC) value of 0.51. Population structure analysis using the Bayesian clustering model approach, distance-based neighbor-joining cluster and principal coordinate analysis using genotypic data grouped the accession into three sub-populations. Population structure analysis revealed that rice accession was moderately structured based on F_ST value estimates. Analysis of molecular variance (AMOVA) and pairwise F_ST values showed significant differentiation among all the pairs of sub-population ranging from 0.152 to 0.222 suggesting that all the three subpopulations were significantly different from each other. AMOVA revealed that most of the variation in rice accession mainly occurred among individuals. The present study suggests that diverse germplasm of NE India could be used for the improvement of root and drought tolerance in rice breeding programmes.

Mithun (Bos frontalis) or gayal and Indian Bison or wild gaur (Bos gaurus) are listed among the rare and endangered bovine species of India. The remote location of mithun in four North Eastern Hill states (Arunachal Pradesh, Nagaland, Manipur, and Mizoram), scattered population size, and non-availability of genetic diversity status are major limitations towards devising a suitable breeding and conservation policy of these species. Since several studies have demonstrated the successful applicability of microsatellite/SSR markers across related genera/families in both crop plants and animal species, 30 FAO recommended cattle microsatellites were utilized for the assessment of the genetic diversity of Indian mithun, bison, and local Tho-tho cattle. Mitochondrial transmembrane protein coding cytochrome B (CYTB) complete sequence data of 71 bovine samples from India were also used to reinforce the study. Population structuring clustered the all bovines into three subgroups as per geographical location and species. Bottleneck analysis indicated a mode shift in the allelic frequency distribution of gaur, indicating minor genetic bottleneck events in the past, while no bottleneck was found in mithun and Tho-tho cattle. To our knowledge, this study represents the first report of molecular genetic characterization showing the population structure and status of genetic diversity in rare Indian bovines, namely, Mithun, Gaur, and Tho-tho cattle.

The study on rice germplasm showed considerable genetic variation in different quality characters analyzed. The grain length varied from 5.10 to 8.03 mm, grain width from 2.00 to 3.17 mm, cooked grain length from 7.40 to 12.37 mm, cooked grain width from 3.30 to 7.17 mm, grain elongation ratio from 1.29 to 2.02 and grain widening ratio from 1.37 to 3.32. On dry weight basis, moisture contents of genotypes ranged from 8.33 to 10.74 per cent, amylose from 0.05 to 29.6 per cent, starch from 70.37 to 82.83 per cent, GC from 53 to 100.03 mm, GT from 2 to 7, crude fat content from 2.64 to 3.76 per cent, crude protein content 8.10 to 10.32 and lysine content from 2.71 to 3.39 (g/100 g of protein). UPGMA based cluster analysis revealed the existence of two major clusters (A and B) with additional sub clusters within each major cluster in indica rice genotypes under study for grain quality data. The difference between GCV and PCV was less for all characters except GT, which indicate greater correspondence between phenotype and genotype and less environmental influence and greater role of genetic factors on expression of grain quality traits. Based on above results amylose content trait would be highly effective to be used in breeding programmes for improving cooking and eating quality.

Nagaland is one of the parts of the center of origin of rice, and has diversified rice landraces with unique cooking quality, taste, aroma and stress tolerance. In current study, landraces were evaluated for grain quality, yield and stress tolerance. Landraces Aongsho, Semmeki, Goyo Tsük and Moya Tsük showed higher yield as compared to Bhalum-3 check variety in the upland ecosystem. Whereas, Mehourü was the smallest landraces with a height of 65 cm. Among all the landraces under study, Yunghah, Goyo Tsük, Rükhatang and Vepvu Tsük were found strongly aromatic. While, Teke, Aongsho and Semmeki landrace showed moisture stress tolerance. Cluster and principal component analysis grouped the landraces into six distinct clusters. These landraces harbor the genes for various grain quality traits, drought tolerance and brown spot disease (Cochliobolus miyabeanus) tolerance. Superior landraces identified for grain quality, drought tolerance and brown spot can be utilized in future breeding programmes. This study may help in pre-breeding activities for development of improved varieties/hybrids for this agro-climatic zone.