Assessment of EST-microsatellites markers for discrimination and genetic diversity in bread and durum wheat landraces fr

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Assessment of EST-microsatellites markers for discrimination and genetic diversity in bread and durum wheat landraces from Afghanistan K. Chabane Æ O. Abdalla Æ H. Sayed Æ J. Valkoun

Received: 28 November 2005 / Accepted: 30 May 2006 / Published online: 24 January 2007  Springer Science+Business Media B.V. 2007

Abstract Accurate and reliable means for identification are necessary to assess the discrimination between landraces of tetraploid wheat [T. turgidum L. subsp. durum (Desf.) Husn.] and hexaploid wheat (T. aestivum L. em. Thell.). In Afghanistan, farmers usually cultivate mixed landraces, and thus distinction between bread and durum is difficult. A set of 18 microsatellites derived from the DuPont ESTdatabase were used to describe genetic diversity in a sample of 82 Afghan wheat landraces. A total of 101 alleles were detected, with allele number per locus ranging from 2 to 13, and a mean allele number of 6.31. The percentage of polymorphic loci was 89%. The EST-SSRs markers showed different level of gene diversity: the highest Polymorphism Information Content value (0.921) was observed with DuPw 221. Our results demonstrated that with a reasonable number of expressed sequences target microsatellites (EST-SSRs) it is possible to discriminate between T. durum and T. aestivum species of K. Chabane (&) Æ J. Valkoun Genetic Resources Unit, International Center for Agricultural Research in the Dry Areas, PO Box 5466, Aleppo, Syria e-mail: [email protected] O. Abdalla Æ H. Sayed Integrated Gene Management Program, MP2, ICARDA, PO Box 5466, Aleppo, Syria

wheat germplasm. Our results showed that ESTdatabases could be a useful source for speciesspecific markers and have the potential for new genic microsatellites markers that could enhance screening germplasm in gene banks. Keywords Afghanistan Æ EST-SSRs Æ Species discrimination Æ T. aestivum Æ Triticum durum

Introduction Wheat is the most important food crop in Afghanistan, covering 80–85% of the arable land, equivalent to 4–8 million hectares. Afghanistan is the third most important center of origin of domesticated crops in the world (Vavilov 1926). Based on the diversity of landraces he collected, Vavilov identified Afghanistan as a center of origin for wheat, barley (Hordeum vulgare L.), chickpea (Cicer arietinum L.), and peas (Pisum sativum L.). Vavilov (1951) identified in Afghanistan 110 varieties of wheat and a progenitor of rye (Secale cereale L.). It is not known what proportion of these earlier-sampled landraces is still cultivated. In Afghanistan, agriculture is still predominantly traditional, where landraces of both tetraploid and hexaploid wheat’s are grown. Hexaploid wheat is indigenous to Afghanistan; hence the probability of bread wheat being the most cultivated crop species in

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the post-conflict war time is the most probable hypothesis. In Afghanistan, farmers usually cultivate mixed landraces where distinction between bread and durum wheat is difficult. A large number of Triticum, Cicer, and Hordeum acce