SSR analysis
The bands of DNA were amplified from five SSR primers against
Dolichos lablab (L.). From the molecular weight of 1636 base pair to 128 base pair, different primers revealed a total of fifty-one bands indicating 88.23 per cent polymorphism (45 bands). The polymorphism varies between 90% and 100%. Banding arrangement with primer AGB 9 generates the largest no. of bands
viz. 15 followed by 11 bands (VM 4); 10 bands (CEDG 198 and DMB SSR 182) while, primer (111) revealed a total of 6 bands which is least (Table 2, Fig 1).
The ten bands generated with primer DMB SSR 182 exhibited 90 per cent of polymorphism. The uppermost band generated at about 1247 bp and the lowest at about 176 bp. Ten bands generated with primer CEDG 198 exhibited 90 per cent of polymorphism. The uppermost band generated at about 822 bp whereas the lowest at about 190 bp. Against primer VM 4, eleven bands were generated; of which polymorphic bands are nine thus revealing 90.90 per cent polymorphism. The uppermost band generated at about 562 bp whereas the lowest at about 128 bp. The pattern of banding generated by primer AGB 9 revealed 15 bands having 80 per cent polymorphism among the accessions considered. The uppermost band generated at about 738 bp and the lowest at 178 bp. Finally, the pattern of banding generated with primer 111 intensified six bands with 100 percent polymorphism rate. The uppermost band generated at about 1636 bp and the lowest at 152 bp (Table 1).
SSR Markers are co-dominant
(Narshimulu et al., 2011) and locus-specific and generally amplify one locus (
Gupta and Varshney, 2000). These markers evaluate the variability and the identification of connections between accessions for breeders
(Li et al., 2011). From the molecular weight of 1636 base pair to 128 base pair, different primers revealed a total of fifty-one bands indicating 88.23 per cent polymorphism. The polymorphism varies between 90% and 100%. Banding arrangement with primer AGB 9 generated the largest no. of bands
viz. 15 while, primer (111) revealed a total of 6 bands which is the least. In evaluating
Dolichos lablab (L.), SSR markers have proven a more accurate variety in genes. In 143 germplasm of bean (Indian) with one hundred and thirty-four SSR markers (
Lablab purpureus), genetic diversity is reported by
Rai et al., (2011). With the 5 RAPD primers, ten
Dolichos lablab (L.) accessions demonstrated major genetic variation. As a result, primer AGB 9 produced max. numbers of bands (15) and bands with a minimum number were revealed by primer 111
i.e. 6. Our findings support
Zhong et al., (2008) and
Zhang et al., (2013) who investigated various markers and identified a large degree of variability between the twenty-four
Dolichos lablab (L.) accessions studied
(Keerthi et al., 2018). The accession classification based on the EST-SSRs was similar to the genomic AFLP and SSR work by
Woodhead et al., (2005). The variation in the band number, governed by various markers
(Kernodle et al., 1993) is induced by the various variable factors like the structure of primer, some annealing site,
etc. The revealed bands also had specific molecular weight to check the distinctions in length between primary connections and the DNA that resulted in band changes (
Devos and Gale, 1992).
Data analysis and polymorphic information content
Performance of marker was checked by the use of different parameters
i.e. polymorphic information content, resolving power, mean resolving power and matrix index. Primer 111 (0.265) has lowest PIC value whereas primer AGB 9 had highest (0.488) with a mean PIC value of 0.390. In compare,
Asare et al., (2010) imply low value of PIC about 0.38 at an average of 3. 8 alleles for every loci in 141 cowpea genotype gathered starting with nine geographic locales for Ghana. In 92 common bean PIC value detected is 0.54 (
Díaz and Buendía, 2011). Similarly,
Benchimol et al., (2007) found a PIC value varied from 0.05-0.83 while studying genetic dry beans diversity with 87 SSR loci the average value of PIC was 0.45. PIC values range from one (very high discriminative power with many alleles in equal frequencies) to zero (which is an indicative of monomorphism) and the higher the PIC value, the more informative is the SSR marker
(Nagy et al., 2012). The value of matrix index ranges from 4.68 (AGB 9) to 1.59 (111) with a mean of 3.2. Higher the MI, better the method is. The value of resolving power ranges from 2.2 to 12.60. The highest value of RP and MRP was recorded for the primer AGB 9 and lowest for primer 111 (Table 2).
Genetic relationship and phylogenetic study
For every marker, genetic relationship among the Genotypes was determine based on Jaccard’s Pairwise similarity coefficient. Genetic Relationships and pooled diversity data by using marker grouped each genotype into its clusters. According to
Beaumont et al., (1998) the genetic gap is any quantitative evaluation of genetic difference at the level of the sequence or the level of allele frequency, measured between persons, populations or species. Pairwise similarity among the genotypes ranged from 0.55 to 0.93 (Primer-AGB-9), followed by 0.33 to 0.89 (Primer-CEDG 198), 0.40 to 0.86 (Primer- VM4), 1 to 0.67 (Primer 111) and 0.33 to 0.86 (Primer DMB-SSR182).
Dendrogram formed was derived from the matrix similarity analysis by UPGMA (Unweighted pair group method with arithmetic averages) cluster analysis by using GenAlEx (Genetic Analysis in Excel, version 6.2) software (
Peakall and Smouse, 2006). Based on the genetic distances with all primers, the UPGMA neighbour-joining tree method generated two distinct clusters for the 10
Dolichos lablab (L.) genotypes
(Hair et al., 1995) (Fig 2). Thus, cluster analysis groups individuals or objects based on characteristics they possess so that individuals with similar descriptions are mathematically gathered into the same cluster
(Atienza et al., 2005).