Application of SSR markers for assessment of genetic similarity and genotype identification in local winter wheat breeding program

Abstract

Background. Simple sequence repeat (SSR) markers are widely used for genetic analysis in plant breeding, allowing for the investigation of genetic divergence and similarity of genotypes, identification of unique alleles and determination of levels of genetic diversity. Materials and Methods. Analysis of 42 wheat cultivars and lines from the bree­ding program of Poltava State Agrarian University was carried out using 11 SSR mar­kers located on different chromosomes. A set of 11 microsatellite single locus primer pairs was used in this study (Xgwm 11, Xgwm 44, Xgwm 46, Xgwm 135, Xgwm 174, Xgwm 186, Xgwm 194, Xgwm 219, Xgwm 312, Xgwm 372, Xgwm 389). Amplification of 11 loci was performed using the Kapa2G FastHotStart PCR Kit (Kapa Biosystems, Boston, USA). The mixture for PCR amplification contained 1.5 x Kapa2G buffer, 0.5 mM dNTP mix, 0.5 μM of each primer (Sigma-Aldrich), 1 unit of Kapa2G FastHotStart DNA Polymerase and 11.8 ng of template DNA in a volume of 25 μl. Fragment lengths were determined using GeneMapper 4.0 software (Applied Biosystems). Dendrogram was constructed using UPGMA (unweighted pair-group method with arithmetic average) in DarWin 6.0 software (Perrier and Jacquemoud-Collet 2006) for clustering analysis. Results and Discussion. The number of alleles detected per locus varied from 5 (Xgwm 11, Xgwm 135, Xgwm 219) to 12 (Xgwm 174). A total of 80 alleles were identified for the 11 loci studied. Among these, 25 unique alleles were found, each of which was present in only one genotype. The polimorphism information content (PIC) values ranged from 0.48 to 0.87. The markers Xgwm 174 (PIC = 0.87), Xgwm 389 (PIC = 0.84) and Xgwm 372 (PIC = 0.83) were the most polymorphic in our study. We obtained a distribution of cultivars and lines by genetic similarity into five clusters. Conclusion. The use of SSR markers made it possible to identify rare alleles within the varieties presented. The study of the genetic similarity of the presented geno­types showed their relationship according to their origin. It was shown that unique alleles tended to occur in certain local breeding genotypes. This study has shown that genotypes representing the local Ukrainian breeding program often have the same allelic variants and at the same time some genotypes have unique allelic variants. The results obtained from the study of 42 winter wheat genotypes based on 11 SSR markers showed that molecular markers can be very useful in assessing genetic similarity and identifying genotypes in the local breeding program.

Keywords

• alleles
• polymorphic information content
• clusters
• triticum aestivum l.