Application of inter simple sequence repeat markers to analyze molecular relationships in wheat (Triticum aestivum L. em. Thell)

Wheat is one of the most important staple food crop and is cultivated throughout the world. High temperature stress is one of the major constrains to wheat production worldwide. This study was undertaken with the objective to assess polymorphism among 14 genotypes (7 thermo-sensitive and 7 thermo-tolerant) of wheat. Genomic DNA of these wheat genotypes was amplified using 40 ISSR primers. Out of 40 primers screened, 26 ISSR primers which produced reproducible alleles were selected for allele scoring. Using these 26 ISSR primers, 187 amplified products were obtained of which 101 were polymorphic. ISSR analysis generated a moderate level of average polymorphism i.e. 52.97%. Average of amplified and polymorphic alleles per primer was calculated as 7.2 and 3.9, respectively. Overall size of PCR amplified products ranged between 220 bp and 3000 bp. Based on similarity matrix data, the value of similarity coefficient ranged from 0.73 to 0.87 with an average genetic similarity of 0.80. Cluster analysis based on ISSR markers discriminated all the wheat genotypes into two major clusters, one consisted of thermo-sensitive genotypes and other had all thermo-tolerant genotypes along with one thermo-sensitive genotype S1 (WH157). ISSR-24 amplified «2200bp band which was present in all 7 thermo-sensitive genotypes but absent in all thermo-tolerant genotypes. The above identified marker may potentially be used in marker assisted selection to develop thermo-tolerant wheat varieties.