Molecular diversity of Omani wheat revealed by microsatellites: II. Hexaploid landraces

Abstract

For millennia, wheat (Triticum spp.) has been grown in traditional aflaj-irrigation systems of remote mountain oases in Oman. However, little is known about the diversity of the ancient landraces used. Given recent reports about the occurrence of novel germplasm in such material, the objective of this study was to evaluate the genetic diversity of hexaploid wheat (Triticum aestivum L.) landraces in relation to their geographic origin using microsatellites. The collection covered most of the cultivation areas in northern Oman where wheat landraces are growing. Total genomic DNA was extracted from six pooled plants representing each accession. A total of 161 wheat accessions were assayed using 35 microsatellite loci in which a total of 305 polymorphic bands were recorded for the 35 microsatellites. The polymorphic information content (PIC) across the 35 microsatellite loci ranged from 0.02 to 0.89 with an average of 0.50. A heterozygosity percentage value of 9.09 was determined and the highest level recorded for accessions from the Batinah district. Rare alleles averaged 1.85 with the highest value being from the Dakhilia district. The results indicated a significant correlation between gene diversity and number of alleles across districts. The correlation coefficient between these two variables over the 35 loci was 0.657, whereby correlation coefficients of 0.718, 0.706, 0.657 and 0.651, respectively, were found for the Batinah, Dhahira, Dakhilia and Sharqia materials. Genetic distances indicated that all landraces were closely related. The cluster analysis discriminated most of the landraces accessions. However, it failed to achieve region-specific groupings of landraces. The present study demonstrated the presence of high diversity in Omani landraces and also indicated the effectiveness of microsatellites to describe it.

Investigation of Genetic Diversity among Bread Wheat Cultivars (Triticum aestivum L.) Using SSR Markers

“…Although SSR or microsatellite markers are often of multi-allelic nature, co-dominant inheritance, relative abundance, and extensive genome coverage were observed (Gupta & Varshney, 2000). Microsatellite markers are useful and becoming popular for different applications in wheat breeding due to their high level of polymorphism and easy handling (Devos et al, 1995;Roder et al, 1995;Bryan et al, 1997;Roy et al, 1999;Lelley et al, 2000) and are used to evaluate genetic diversity of hexaploid wheat (Al Khanjari et al, 2007). In the present study SSR markers almost succeeded in discrimination wheat cultivars.…”

Genetic diversity of Cameroonian bread wheat (Triticum aestivum L.) cultivars revealed by microsatellite markers

“…On the other hand, Al-Khanjari et al (2007) found that all local varieties of wheat from the same geographical area clustered in the same group. In our case, we can hypothesize that the genetic proximity of the cultivars based on their geographical origin results from a local selection and diversification, coupled with weak or nonexistent exchanges of seeds between regions, inducing a geographical structuration and a form of isolation by distance.…”

Molecular and Elemental Characterization of Selected Turkish Durum Wheat Varieties

“…Other than these properties, genetic diversity studies of diverse accessions is strengthen by the advancement and thriving appliance of various types of molecular markers (Khan et al, 2014). For more than two decades, simple sequence repeats (SSRs) or microsatellite markers (Tautz et al, 1986) have been progressively used for diversity analysis of native and contemporary cultivars (Todorovska et al, 2005;Al Khanjari et al, 2007;Colomba and Gregorini, 2011) and has shown promising polymorphism.…”