Exploring the Molecular Variability of Diverse Black gram (Vigna mungo L. Hepper) Genotypes Using SSR Markers
Abstract
This investigation aimed to explore the molecular diversity of 117 black gram genotypes employing Simple Sequence Repeats (SSR) markers. Out of 43 SSR markers studied, 15 markers showed polymorphism. Polymorphic Information Content (PIC) values ranged from 0.4 to 0.7 with a mean of 0.6. A total of 52 alleles, ranging from three to four with a mean of 3.4 alleles per locus, were detected. Population structure analysis grouped the 117 genotypes into four sub-populations. UPGMA cluster analysis grouped the genotypes into three main clusters: Cluster I (51 genotypes), Cluster II (19 genotypes), and Cluster III (47 genotypes). Principal coordinate analysis indicated that the genotypes were distinctly separated from one another. The results of the unweighted neighbor-joining clustering tree and PCoA analysis were in close correspondence with the results of model-based STRUCTURE analysis. The findings provide valuable insights into the genetic diversity of black gram, which can assist plant breeders in developing improved cultivars.
Keywords
Simple Sequence Repeats (SSR) Markers
Polymorphic Information Content
Genetic Diversity
Population Structure
Black gram.
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Introduction
Black gram (Vigna mungo L. Hepper) is a short-duration, cleistogamous, self-pollinating, diploid species with a chromosome number (2n-2x-22) and a genomic size of 574 mega base pairs (Mbp). It is a member of the Leguminaceae family (Gupta et al., 2008). India is the world's largest user and producer of black gram. Black gram in India is cultivated extensively over an area of about 4.6 million hectares (Mha), with annual production and productivity of 24.5 lakh tonnes and 533 kg per hectare, respectively. In Andhra Pradesh, black gram is grown over an area of 3.93 lakh ha with 3.65 lakh tonnes production and 929 kg ha⁻¹ productivity (2020-21) (www.agricoop.nic.in). According to El-Karamany (2006), most nutrients, including vitamins, minerals, and amino acids, are abundant in black gram, with proteins making up 25–26%, carbohydrates 60%, and fats 1.5%. It is high in vitamins A, B1, and B3, and contains trace amounts of riboflavin, niacin, and vitamin C.
As one of the most valued pulses in India and Pakistan, black gram is native to India and has been grown there since ancient times. Grown practically throughout India, this leguminous pulse has become the most renowned and is appropriately called the "king of the pulses." Asia, Pakistan, Myanmar, and other southern Asian nations are the main growing regions. Black gram is a member of the genus Vigna and the family Leguminaceae.
Conclusion
From the results of population structure analysis, the maximum value for Evanno's measure of ΔK showed a clear peak at an optimal K value of four (K = 4), which indicated that the entire population can be grouped into four subgroups. Diversity analysis using DARwin based on the unweighted neighbor-joining method segregated black gram germplasm into three main clusters: Cluster I, Cluster II, and Cluster III. The grouping of genotypes based on UPGMA clustering and PCoA analysis was in close correspondence with the results of model-based STRUCTURE analysis, which further confirmed the population structure results. The identified polymorphic SSR markers, particularly those with high PIC values (CEDG 128, CEDG 44, TWSSR 87, CEDG 154, CEDG 53, CEDG 92, and CEDG 91), can be effectively utilized for future genetic diversity studies and marker-assisted selection programs in black gram.
References
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