Analysis of genetic diversity in Tunisian durum wheat cultivars and related wild species by SSR and AFLP markers

Abstract

Thirty-four durum wheat cultivars representing the Tunisian durum (Triticum durum Desf.) wheat collection and seven wild species of wheat relatives (Triticum turgidum L., T. dicoccon Schrank., T. dicoccoides (Kö rn) Schweinf., T. araraticum Jakubz., T. monococcum L., Aegilops geniculata Roth, and Aegilops ventricosa Tausch) were analysed with amplified fragment length polymorphism (AFLP) and microsatellite (SSR) markers. Both marker systems used were able to differentiate durum wheat cultivars from the wild relatives and to specifically fingerprint each of the genotypes studied. However, the two marker systems differed in the amount of detected polymorphisms. The 15 SSR markers were highly polymorphic across all the genotypes. The total number of amplified fragments was 156 and the number of alleles per locus ranged from 3 to 24 with an average of 10.4. Two SSR markers alone, Xwms47 and Xwms268, were sufficient to distinguish all 34 durum wheat genotypes. The five AFLP primer pair combinations analysed yielded a total of 293 bands, of which 31% were polymorphic. The highest polymorphic information content (PIC) value was observed for SSRs (0.68) while the highest marker index (MI) value was for AFLPs (7.16) reflecting the hypervariability of the first and the distinctive nature of the second system. For durum wheat cultivars, the genetic similarity values varied between 31.3 and 81% for AFLPs (with an average of 54.2%), and between 3.6 and 72.7% for SSRs (with an average of 19.9%). The rank correlation between the two marker systems was moderate, with r ¼ 0.57, but highly significant. Based on SSR markers, highest genetic similarity (GS) values were observed within the modern cultivars (37.3%), while the old cultivars showed a low level of GS (19.9%). Moreover, the modern cultivars showed low PIC and MI values. UPGMA Cluster analysis based on the combined AFLP and SSR data separated the wild wheat species from the durum wheat cultivars. The modern cultivars were separated from the old cultivars and form a distinct group.

Molecular characterization of genetic variation in somaclones of durum wheat (Triticum durum Desf) using SSR markers

“…The locus gwm131 was the most polymorphic, followed by the locus gwm427. Our results are in agreement with the studies of Medini et al (2005) and those of Colomba and Gregorin (2011) conducted on different durum populations and showed the existence of a higher genetic diversity estimated on the base of the use of SSR and AFLP markers. Hamrick and Godt (1997) reported that intra-population genetic diversity of crosspollinated species varies from 10.3% to 26.6%, whereas intra-population genetic diversity of self-pollinated species varies from 0.09% to 0.14%.…”

Geographical diversity pattern in Iranian landrace durum wheat (Triticum turgidum) accessions using start codon targeted polymorphism and conserved DNA-derived polymorphism markers

“…Genetic diversity in different durum wheat germplasm has been estimated using AFLP (Medini et al 2005;Mardi et al 2011), SSR and SSAP (Mardi et al 2011) and AFLP markers (Maccaferri et al 2007), but studies on the genetic diversity of Iranian landrace durum wheat are limited. The largest variability for yield and yield-related traits was recorded in Iranian durum wheat landraces, which is in agreement with its proximity to the Fertile Crescent, the origin for domestication of wheat (Harlan 1986;Fayaz et al 2013).…”

Genetic resources of barley and oat characterised by microsatellites

“…In addition, microsatellites exhibit a codominant inheritance (Hernández et al 2002), which is essential for effective discrimination between closely related lines (Akkaya et al 1992). Microsatellite markers are currently used to identify genotypes, quantitative trait loci (QTLs) and genetic diversity (Leišová & Ovesná 2001;Medini et al 2005;Roussel et al 2005).…”