Molecular Diversity Analysis in Tomato (Solanum lycopersicum L.) Using SSR Markers

Abstract

The current experiment was conducted at the PG Research Block, College of Horticulture, Rajendranagar, Hyderabad, during Kharif 2017- 2018 to determine the genetic diversity of 40 tomato genotypes at the molecular level using SSR primers. Genomic DNA from each genotype was extracted and quantified for molecular characterization using agarose gel electrophoresis. Then, PCR amplification by using 100 SSR markers was done. The collected data were aligned for the construction of cluster analysis and a similarity matrix. The cluster analysis of 40 genotypes was constructed using NTSYS software based on the Unweighted Paired Group of Arithmetic Mean Average (UPGMA). Using NTSYS software, a tree-like dendrogram was constructed. Genotypes were divided into clusters, sub-clusters, and sub-sub-clusters based on their genetic diversity, and linkage distance was calculated. An aggregate of 100 simple sequence repeat (SSR) markers has been chosen for diversity analysis. Of these, 51 markers showed a good amplification pattern in all the genotypes with 193 alleles. In the remaining 49 SSR markers, plenty of missing values were there with poor amplification patterns. The polymorphic bands had been scored visually as present (1) or absent (0) on a binary matrix. The Polymorphic Information Content (PIC Value) of each SSR primer was determined, with values ​​ranging from 0.18 (TGS-2261) to 0.97 (TGS-2080 and TES-559), with an average value of 0.816. The dendrogram allowed the genotypes analyzed to be grouped based on their genetic similarity. The similarity coefficients ranged between 0.17 and 0.83. The tomato genotype EC- 631349 was found to be the most diverse and significantly superior in terms of plant height (191.56 cm), number of primary branches (9.83), number of fruits per plant (323.00) and ascorbic acid (59.43mg/100gm), genotype EC-313466 was identified to be early as noted from the character days to first flowering (21.26 days) and days to 50% flowering (29 days). The accession EC-514013 was detected to be superior for TSS (8.16 0Brix).