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Estimation of genetic diversity is a prerequisite to select genetically diverse parents. Availability and collection of genetically diverse parents contribute significantly towards the selection and utilization of promising parents in plant breeding to develop a commercial variety or hybrid. Germplasm is an important source for various qualitative and quantitative traits that may be used to introgress through combination breeding for the improvement of the existing cultivars or development of new cultivars and hybrids by using marker assisted selection. Genetic diversity refers to the variations among the alleles of a gene and it may be examined at nucleotide level in the DNA sequence. Various classical and DNA tools are available to access genetic diversity at morphological and molecular levels and can be expressed in the form of dendrogram, percentage polymorphic loci and genetic distance. Estimation of genetic diversity using molecular techniques is more reliable as it is based on highly polymorphic molecular markers which remain unaffected by the influence of environment. Genetically diverse genotypes are used as valuable source by the plant breeders for the development of new or improved crop varieties with desirable traits to cope up the biotic and abiotic stresses such as drought tolerant, salt tolerant, insect pest and disease resistance etc. This article reviews various traditional to molecular methods used in estimation of genetic diversity and their exploitations in plant breeding programme. Keywords clusters * genetic diversity * genetic vulnerability * metroglyph * molecular markers, Introduction The major objective of plant breeding programmes is to increase the yield and improve other important traits, which depends on nature and magnitude of genetic variability available in the [...]

Horsegram (Macrotyloma uniflorum) - an important, self-pollinated food legume, however due to limited genomic and genetic resources the genetic improvement could not be achieved as compare to other major legumes. Our work aims at finding novel microsatellite markers and their use for the construction of a linkage map from 157 individuals of F9 recombinant inbred lines (RILs) of horsegram. The determinate growth habit and plant height are important traits for its suitability for different cropping systems. The genotypic data were generated by screening 2 395 molecular markers, of which 600 (25.05 %) polymorphic markers were selected. Two-hundred eighty-seven markers were mapped on ten linkage groups (LGs) at a log of odds (LOD) of 3.5 straddling 796.76 cM with 2.78 cM of marker density. For the identification of the quantitative trait loci (QTLs), the phenotypic data recorded on the RILs for the plant height and growth habit were analysed using the statistical tools JoinMap® and Windows QTL cartographer, based on the composite interval mapping (CIM) technique. Across the ten linkage groups, we detected four QTLs (LOD ≥ 2.5) for four traits. All the traits were major QTLs as indicated by the percentage of phenotypic variance (PVE) (≥ 10%) that ranged from 13.5% to 40.3%, therefore, this is very important information which can be used in marker-assisted selection (MAS). The present genomic information generated in this orphan crop, thus, provides the base for genetic improvements by devising molecular breeding strategies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Macrotyloma uniflorum (horsegram) is cultivated in the alpine Himalayas for its nutritional benefits. The chemical diversity of M. uniflorum has been explored by several research groups, but none has reported the chemical signature to monitor the identity and quality. To overcome quality control problems and provide more accurate chemotype information, proton nuclear magnetic resonance (1H‐NMR)‐based chemical signature and tentative metabotype discrimination was studied. RESULTS: Metabolites were identified by characteristic chemical shifts and their correlations in one‐dimensional (1D) and two‐dimensional (2D) nuclear magnetic resonance (NMR) experiments. The identifications were confirmed by reference standards, with in‐house databases, and with public databases. From the analysis of seed samples from eight locations, NMR detected 46 diversified metabolites, including 18 amino acids, nine carbohydrates, three vitamins, seven flavonoids, and nine miscellaneous molecules (fatty acids/choline/phenolics/organic acids/sterols). These metabolites generated a single snapshot chemical signature for M. uniflorum. Greater content of identified metabolites was found at high elevations of 1829 m (55.78 g kg−1) followed by 1000–1150 m (19.30–17.23 g kg−1) and 1150–1450 m (7.33–13.41 g kg−1). Principal component analysis of samples revealed that chemotypes grouped into three distinct clusters. 'Cluster‐3' was positively correlated with metabolites and found the best nutritionally enriched chemotype. CONCLUSIONS: A proton nuclear magnetic resonance‐based M. uniflorum chemical signature was generated for the first time. The environmental conditions of 1829 m were most suitable for obtaining nutritionally enriched M. uniflorum crops. Overall, this information could help in the conservation, quality control, product development, and agriculture inventions of M. uniflorum. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Valeriana jatamansi, a medicinally important species of the family Valerianaceae, has been cytologically studied in different geographical areas of North-Western Himalayan region of India. Te tetraploid cytotype with chromosome numbers 2n=32 is in conformity with the earlier reports of the species from different parts of the world. An octoploid cytotype (2n=64) makes a new addition for the species on a worldwide basis, whereas the diploid cytotype (2n=16) is new to India have been reported for the first time in India. Tese cytotypes (2n=16, 32, 64) show significant variations with respect to morphology as well as geographical distribution in the Western Indian Himalayas. Further, anomalous populations have been marked with meiotic abnormalities in the form of cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges resulting in abnormal microsporogenesis, and production of heterogeneous-sized fertile pollen grains along with reduced pollen fertility. [ABSTRACT FROM AUTHOR]