MOLECULAR DIVERSITY STUDIES IN SESAME (Sesamum indicum L.)
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Date
2019
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Acharya N G Ranga Agricultural University, Guntur
Abstract
The present study was carried out with thirty genotypes of sesame for characterization based on 20 DUS characteristics of PPV&FRA (Agricultural Research Station, Yelamanchili, Visakhapatnam District of Andhra Pradesh) and molecular diversity analysis using SSR markers (Advanced Post Graduate Centre, Lam , Guntur).
The DUS characters, branching pattern (basal), leaf size (large), leaf serration (serrate), flower petal colour (light purple), flower petal hairiness (dense), locule number/capsule (four), capsule shape (broad oblong), capsule number/leaf axil (one) and capsule arrangement (alternate) showed no variability. The characters, days to 50% flowering, plant height (cm), plant branching, stem hairiness, leaf lobes, capsule hairiness, capsule length (cm), days to maturity, seed coat colour, 1000 seed weight (g) and oil content (%) showed variability phenotypically and are considered for the identification and characterization of genotypes.
The cluster analysis based on eleven variable DUS characteristics grouped the genotypes into 5 clusters at 85 % similarity. The similarity level (85 to 100 %) in the clustering pattern clearly indicated the presence of sufficient variability for few traits among the genotypes for differentiation.
The molecular characterization with 50 SSR primers revealed the use of 45 primers for characterization as they produced clear banding pattern. Only seven primers showed polymorphism and total number of bands produced were 191 with 7 primers. The number of alleles per locus was varied from 2 to 6 with an average of 3.57 alleles per locus. The size of the scoring bands ranged from 120 to 300 bp. PIC values of
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primers ranged from 0.28 to 0.80 with an average value of 0.47. The Number of effective alleles (Ne) ranged from 1.38 to 4.86 with an average of 2.49. Average expected heterozygosity (He) values ranged from 0.27 to 0.79 with an average of 0.53. The Average Shannon’s diversity index (Ic) was 0.95 with the range of 0.40 to 1.65. These allele diversity values indicated the high level of informativeness of these markers in the present material.
The dendrogram prepared from the UPGMA grouped the genotypes into 4 clusters and a clade at similarity coefficient value of 0.85. The similarity coefficient values range was 0 to 1. The cluster-I had 12 genotypes while the clusters-II, III and IV had five, seven and five genotypes, respectively, indicating the existence of sufficient variability in the lines studied. The clade had one genotype (MLTS-1). Further, the similarity coefficient values indicated the very close relatedness among the genotypes of GOURI and MADHAVI; GOURI and YLM-164; MADHAVI and YLM-164; YLM149 and YLM-150; MLTS-7 and YLM-148; MLTS-8 and TKG-22. The similarity values were minimum between the genotypes of the clusters II and IV indicating their exploitation. The released varieties were grouped into the cluster I while the MLTS genotypes were grouped into the cluster IV indicating their high level of genetic similarity among the genotypes present in these clusters.
Thus, the preliminary study on DUS characterization and molecular diversity in sesame genotypes of ARS, Yelamanchili revealed the presence of sufficient variability at both morphological and molecular levels. The comparative study involving both morphological and molecular data indicated that there is no correlation among the genotypes grouped in clusters. This study also reported the potentiality of SSR markers for studying the genetic relatedness among the genotypes of sesame.
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D5773
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