Rizky Pasthika Kirana, Sebastian Michel, Jose Moreno-Amores, Noemie Prat, Marc Lemmens, Maria Buerstmayr, Hermann Buerstmayr & Barbara Steiner

Theoretical and Applied Genetics; September 2023; vol. 136: 201

Key message

FHB resistance of durum wheat was improved by introgression of Fhb1 and resistance genes from emmer wheat and by selection against adverse alleles of elite durum wheat.

Abstract

Durum wheat is particularly susceptible to Fusarium head blight (FHB) and breeding for resistance is impeded by the low genetic variation within the elite gene pool. To extend the genetic basis for FHB resistance in durum wheat, we analyzed 603 durum wheat lines from crosses of elite durum wheat with resistance donors carrying resistance alleles derived from Triticum aestivum, T. dicoccum and T. dicoccoides. The lines were phenotyped for FHB resistance, anthesis date, and plant height in artifcially inoculated disease nurseries over 5 years. A broad variation was found for all traits, while anthesis date and plant height strongly infuenced FHB severities. To correct for spurious associations, we adjusted FHB scorings for temperature fuctuations during the anthesis period and included plant height as a covariate in the analysis. This resulted in the detection of seven quantitative trait loci (QTL) afecting FHB severities. The hexaploid wheat-derived Fhb1 QTL was most signifcant on reducing FHB severities, highlighting its successful introgression into several durum wheat backgrounds. For two QTL on chromosomes 1B and 2B, the resistance alleles originated from the T. dicoccum line Td161 and T. dicoccoides accessions Mt. Hermon#22 and Mt. Gerizim#36, respectively. The other four QTL featured unfavorable alleles derived from elite durum wheat that increased FHB severities, with a particularly negative efect on chromosome 6A that simultaneously afected plant height and anthesis date. Therefore, in addition to pyramiding resistance genes, selecting against adverse alleles present in elite durum wheat could be a promising avenue in breeding FHB-resistant durum wheat.

See https://link.springer.com/article/10.1007/s00122-023-04426-7

Fig.3: Manhattan and Q–Q plots of the SNP associations with best linear unbiased estimates (BLUEs) for a FHB severity (AUDPC_corrected) after thermal accumulation correction and plant height as a covariate, b anthesis date and c plant height in the durum wheat population across the 2012–2020 trials. The horizontal dotted line shows the − log10 p value with FDR 5% significant threshold