Genetic diversity in a durum wheat collection for morphological traits, biochemical and molecular markers.

During the past decades old durum wheat varieties were replaced by a limited number of improved varieties, selected to perform well under intensive crop management, resulting in the loss of genetic resources useful for future breeding programs. The interest towards organic, low-input agricultural systems and the new focus on local products have highlighted the need to re-introduce into cultivation old accessions. “Ex situ” collections may have a considerable percentage of genetic diversity and useful traits for future breeding needs because of their wide variability in terms of phenological, morphological and quality traits. Thus, a comprehensive characterization of germplasm collections is a prerequisite for understanding the extent of genetic variability and ensuring the genetic resources conservation and subsequent utilization. In this study 132 durum wheat accessions collected in Southern Italy since 1947 and now preserved “ex situ” in genebanks were evaluated through quanti-qualitative morphological traits, biochemical markers and molecular markers. A huge variability emerged for all the observed morphological traits. 53% of the accessions showed fusiform ear, 35% oblong ear and 12% elliptic ear. The analysis of variance for quantitative traits was significant for the following characters: plant height, ear length, length of awns, number of spikelets per spike, number of seeds per spike, seed length, seed weight per spike, and weight of 1000 seeds. Biochemical characterization of gliadins subunits established that 49 accessions possessed gliadin γ-42 and 35 γ-45. In the α region were identified patterns having from 2 to 6 bands; in the β region patterns with 1 to 5 bands; in the γ region patterns having from 1 to 6 bands and in the ω region patterns with 1 to 9 bands. The analysis of the high molecular weight glutenin subunits (HMW-GSs) evidenced that in the collection there were 19 different patterns. The molecular markers (SSR) identified a total of 115 alleles, with 3.83 alleles per locus. Results of this study highlighted a huge variability for the examined parameters, suggesting that genetic diversity was available in the whole germplasm collection, and that the collection can represent a valuable genetic resource for future wheat breeding programs