Nowadays cereal crop improvement must cope with the increased requirements posed by the climate change effects on: (i) phenology, (ii) resilience to abiotic stresses (drought and heat), and (iii) susceptibility to diseases. Altogether, this requires boosting the efficiency of traditional selection methods, particularly considering the potential of genomics on improving the efficiency of selection.

Durum wheat (BBAA) is a major cereal for the Mediterranean basin and belongs to the highly diverse tetraploid wheat gene pool, including 11 T. turgidum subspecies all interfertile with common wheat (BBAADD). Contrary to tetraploids, the hexaploid common wheat originated from two domestication bottlenecks (wild emmer to domesticated emmer and durum for the BBAA genomes and goatgrass to wheat for the DD genome) and the depletion in diversity as compared to its ancestors is even stronger. Hence, the tetraploid germplasm can be considered a valuable resource for both durum and bread wheat improvement. Tetraploid germplasm has spread from the Fertile Crescent across Europe, North Africa, Asia, India and Ethiopia. The evolution has produced a huge diversity valuable for adaptation to abiotic and biotic stresses.

Based on an international effort, we have assembled a comprehensive global durum wheat resource comprising (i) theTetraploid wheat Global Collection (TGC, 1,856 accessions), including wild and domesticated emmer and landraces of durum wheat and related subspecies, (ii) the Global Durum Panel (GDP; 1,033 accessions) including cultivated and locally grown durum wheat varieties from worldwide, and (iii) the Tetraploid wheat Core Collection (TCC; 350 accessions) capturing 90% of the haplotype diversity. The iSelect 90K SNP array anchored to the Svevo genome sequence allowed us to study population structure and perform haplotype and GWAS analysis. Passport and genotypic data of the Global Durum Resource are available in GrainGenes . GDP, TGC and TCC are being characterized in various ways to dissect the QTLome for resistance to yellow rust, leaf rust, soil-borne cereal mosaic virus (SBCMV), root growth angle (RGA) and ear fertility traits. Preliminary genome wide association (GWAS) results and the use of haplotype information to develop diagnostic KASP® markers valuable for marker-assisted selection and narrow down the candidate gene intervals will be presented for key traits.

The combined analysis of these resources allowed to identify novel QTL, cross-validate major QTLs as well as trace the origin, spread and phenotypic effects of valuable haplotypes at target loci. The Global Durum Resource provides unprecedented opportunities to exploit at best the native diversity of the A and B genomes for the identification and deployment of novel beneficial haplotypes in both durum and common wheat.