Molecular analysis of soybean varying in water use efficiency using SSRs markers

A set of 91 soybean germplasm lines, collected from different parts of the world, were screened for Water Use Efficiency (WUE) using Carbon Isotope Discrimination (CID) technique and were characterized for 10 quantitative traits. After screening under field condition, 44 soybean genotypes showed variations in WUE. Molecular diversity of these 44 diverse soybean lines was carried out with 26 Simple Sequence Repeats (SSRs) markers, of which 10 were polymorphic (38.47% polymorphism). 28 alleles were observed which were distributed over 10 loci, with an average of 2.8 alleles per locus. Polymorphism Information Content (PIC) value of 10 polymorphic markers ranged from 0.40 (locus Satt460) to 0.67 (locus satt260), with an average of 0.46. Pair-wise genetic similarity value, as calculated by simple matching coefficient, ranged from 0.99 to 0.40, with an average of 0.70. Genotypes were clustered using NTSYS-pc software employing unweighted paired group method using arithmetic averages to generate the dendrogram. Dendrogram exhibited 8 distinct clusters with a similarity coefficient of 0.69. Genotypes having low to medium and medium to high CID value were clustered in distant groups indicating usefulness of these polymorphic SSRs markers for differentiating genotypes on the basis of their CID value. The findings of this study indicate the need for broadening genetic base of the present Indian soybean cultivars through use of exotic sources of variation towards WUE. Thus, diverse genotypes identified in this study would be beneficial to soybean breeders to develop mapping population to identify QTLs for WUE.