Genetic dissection of resistance to abiotic and biotic stresses in durum wheat

This thesis was aimed to investigate the genetic response to abiotic and biotic stresses in durum wheat (Triticum turgidum L. var. durum), a cultivated tetraploid subspecies used for the production of pasta, couscous and various types of bread. Two research areas were focused: i) the high-throughput phenotyping (HTP) to detect novel drought tolerance quantitative trait loci (QTL) clusters and ii) the Kompetitive Allele Specific Polymerase chain reaction (KASP) marker development for the genetic dissection of Furarium head blight (FHB) resistance. Concerning the first area, I investigated drought adaptive traits on durum wheat elite accessions at Maricopa Agricultural Center (University of Arizona, US) which provided the experimental field and the high-throughput phenotyping platforms. The genome-wide association study (GWAS) detected thirty-one QTL clusters for two or more drought adaptive traits unrelated to the major loci responsible for phenology and plant height. Twelve of them overlapped with the major QTL for grain yield and related traits previously reported in studies carried out across a broad range of soil moisture availability and field drought conditions in wheat. Concerning the second area, I investigated two plant materials: i) 130 durum wheat accessions artificially inoculated with Fusarium culmorum and F. graminearum species and evaluated for incidence (INC), severity (SEV), FHB index, Fusarium-damaged kernels (FDK) and deoxynivalenol (DON) content; ii) 165 F6 recombinant inbred lines (RILs) from the cross between the cultivars Simeto and Levante evaluated for SEV using FG as inoculum. The genetic dissection led to sixteen QTL clusters, in part unrelated to the phenology and unknown in bread wheat, from which specific loci significantly influenced DON content. The haplotype analysis allowed me to validate KASP Single Nucleotide Polymorphisms (SNPs) suitable for marker-assisted selection (MAS) programs and to select cultivars for resistance/tolerance to DON content and other FHB traits.