Genetic diversity analysis of the durum wheat Graziella Ra, Triticum turgidum L. subsp. durum (Desf.) Husn. (Poales, Poaceae).

For the first time, the durum wheat Graziella Ra was compared to four Italian durum wheat varieties (Cappelli, Grazia, Flaminio and Svevo) and to Kamut in order to preliminary characterize its genome and to investigate genetic diversity among and within the accessions by Amplified Fragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs) and α-gliadin gene sequence analysis. The main aim of the study was an attempt to determine the relationship between the historic accession Graziella Ra and Kamut which is considered an ancient relative of the durum subspecies. In addition, nutritional factors of Graziella Ra were reported. Obtained results showed that (i) both AFLP and SSR molecular markers detected highly congruent patterns of genetic diversity among the accessions showing nearly similar efficiency; (ii) for AFLPs, percentage of polymorphic loci within accession ranged from 6.57% to 19.71% (mean 12.77%) and, for SSRs, from 0% to 57.14% (mean 28.57%); (iii) principal component analysis (PCA) of genetic distance among accessions showed the first two axes accounting for 58.03% (for AFLPs) and 61.60% (for SSRs) of the total variability; (iv) for AFLPs, molecular variance was partitioned into 80% (variance among accessions) and 20% (within accession) and, for SSRs, into 73% (variance among accessions) and 27% (within accession); (v) cluster analysis of AFLP and SSR datasets displayed Graziella Ra and Kamut into the same cluster; and (vi) molecular comparison of α-gliadin gene sequences showed Graziella Ra and Kamut in separate clusters. All these findings indicate that Graziella Ra, although being very similar to Kamut, at least in the little part of the genome herein investigated by molecular markers, may be considered a distinct accession showing appreciable levels of genetic diversity and medium-high nutritional qualities.