| Abstrakt: |
Introduction: The recent boosting of genomic data in durum wheat (Triticum turgidum subsp. durum) offers the opportunity to better understand the effects of breeding on the genetic structures that regulate the expression of traits of agronomic interest. Furthermore, the identification of DNAmarkers useful formarker-assisted selection could also improve the reliability of technical protocols used for variety protection and registration. Methods: Within this motivation context, 123 durum wheat accessions, classified into three groups: landraces (LR), ancient (OC) and modern cultivars (MC), were evaluated in two locations, for 34 agronomic traits, including UPOV descriptors, to assess the impact of changes that occurred during modern breeding. Results: The association mapping analysis, performed with 4,241 SNP markers and six multilocus-GWAS models, revealed 28 reliable Quantitative Trait Nucleotides (QTNs) related to plant morphology and kernel-related traits. Some important genes controlling flowering time and plant height were in linkage disequilibrium (LD) decay with QTNs identified in this study. A strong association for yellow berry was found on chromosome 6A (Q.Yb-6A) in a region containing the NADH-UBIQUINONE OXIDOREDUCTASE subunit, a gene involved in starch metabolism. The Q.Kcp-2A harbored the PPO locus, with the associated marker (Ku_c13700_1196) in LD decaywith Ppo-A1 and Ppo-A2. Interestingly, the Q.FGSGls-2B.1, identified by RAC875_c34512_685 for flag leaf glaucosity, mapped less than 1Mb from the EPISTATIC INHIBITORSOF GLAUCOUSNESS (Iw1), thus representing a good candidate for supporting the morphological DUS traits also with molecular markers. LD haplotypeblock approach revealed ahigherdiversity, richness andlength of haploblocks inMCthan OCand LR (580 in LR, 585 inOCand 612 inMC), suggesting a possible effect exerted by breeding programs on genomic regions associated with the agronomic traits. Discussion: Our findings pave new ways to support the phenotypic characterization necessary for variety registration by using a panel of cost-effectiveness SNP markers associated also to the UPOV descriptors. Moreover, the panel of associated SNPsmight represent a reservoir of favourable alleles to use in durum wheat breeding and genetics. [ABSTRACT FROM AUTHOR] |
