Global Durum Wheat Panel: A Genetic Tool for Durum Wheat Breeding

ELISABETTA MAZZUCOTELLI; ET AL.; HANS-JOACHIM BRAUN; ROBERTO TUBEROSA; LUIGI CATTIVELLI; ANNA MARIA MASTRANGELO; AHMED AMRI; MICHAEL BAUM; MARCO MACCAFERRI; PABLO F RONCALLO; KARIM AMMAR; FILIPPO BASSI

San Diego, CA,

Conferencia; International Plant & Animal Genome XXVIII; 2020

Scherago International

A Global Durum Wheat Panel (GDP) of 1,011 genotypes was established through a cooperative effort of durum wheat scientists within the framework of the Expert Working Group on Durum Wheat Genetics and Breeding, part of the Wheat Initiative. Following extensive genotyping with the wheat iSelect 90K SNP assay and a process of selection, nearly 20,000 unique, non-redundant, single Mendelian SNP markers that were both genetically and physically mapped were used to characterise the GDP for linkage disequilibrium (LD), genetic diversity, population structure and genetic relationships. According to the analysis with Admixture, grouping statistics stabilized at K > 11. A refined analysis was carried out on 473 durum wheat cultivars representing 12 breeding programs from all-around the world. Following an analysis of molecular variance, the highest proportion of variance was observed within groups (> 88%) partitioned based on breeding group and year of release. Moderate levels of genetic diversity were observed for the breeding programs considered, ranging from 0.30 for Icarda and Cimmyt groups up to 0.41 for the Ethiopian modern germplasm. A moderate but continuous decrease of genetic diversity (from 0.38 to 0.34) was observed with respect to the year of release, across groups of cultivars released in decades from 1970 to 2018. Finally, four genome-wide selection indexes (Fst, DRI, XP-EHH and XP-CLR) estimated chromosome regions putatively subjected to selection in comparisons of both landrace vs. cultivar subpopulations and between cultivar subpopulations.