Studying genetic diversity and population structure of bread wheat (Triticum aestivum L.) genotypes using microsatellite markers

Document Type : Research Paper

Authors

1 Department of Genetics and Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

2 Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia, Iran.

3 Department of Genetics and Plant Breeding, College of Agriculture, Tarbiat Modares University, Tehran, Iran.

10.22124/cr.2024.27755.1824

Abstract

Introduction
Bread wheat (Triticum aestivum L.) is one of the most important crops in the world. Improving genetic base and diversity can increase wheat yield. Genetic diversity is the basis of selection programs, exploitation of gene pools in breeding activities and evolution of breeding populations. SSR markers are the most popular PCR-based molecular markers widely used to analyze genetic diversity among different plant species. The present study was conducted to investigate the genetic diversity of bread wheat cultivars based on SSR markers.

Materials and methods
Seventy bread wheat cultivars were cultivated in a completely randomized design with three replications at greenhouse in Tarbiat Modares University. Genomic DNA extraction was performed using the Viragen kit and the quality and quantity of DNA samples were determined. Then, 30 pairs of wheat Xgwm microsatellite primers were used for studying diversity and determining genetic distance among bread wheat cultivars. The bands in the gels were scored co-dominantly to distinguish homozygous and heterozygous genotypes.

Research findings
The results showed that 24 pairs of microsatellite primers investigated on bread wheat cultivars showed suitable polymorphism. These primers successfully identified a total of 79 alleles, with an average of 3.29 alleles per marker locus. The number of observed alleles at each locus varied from two to seven, with the primer Xgwm443 identifying the highest number of alleles (seven alleles). The content of polymorphic information (PIC) varied from 0.14 in xgwm129 marker to 0.92 in xgwm174 and Xgwm162 markers with an average of 0.56. Gene diversity varied from 0.15 to 0.97 with an average of 0.62. Comparing the amount of polymorphism information and gene diversity showed that these two parameters have a direct relationship with each other. Cluster analysis based on SSR markers data using the nearest neighbor method grouped the studied genotypes into three subgroups.

Conclusion
This research was designed to assess the genetic diversity of various bread wheat cultivars based on SSR molecular markers. In this study, the primer Xgwm443, which exhibited the highest number of alleles, along with Xgwm174 and Xgwm162, which demonstrated the highest levels of polymorphism, were identified as the most suitable primers. Based on the results of cluster analysis, 70 bread wheat cultivars were classified into three groups. Overall, the obtained results indicate a considerable polymorphism identified by studied SSR markers; therefore they are introduced as useful and appropriate markers for assessing the diversity and differentiation in wheat genotypes and possibly in other cereals. In addition to their application in grouping genotypes, these markers also can be used effectively in identifying genes related to agro-morphological traits in wheat.

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Cereal Research
Volume 14, Issue 4 - Serial Number 53
February 2025
Pages 365-380

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