Dissection of a grain yield QTL from wild emmer wheat reveals sub-intervals associated with culm length and kernel number

Abstract

Genetic diversity in wheat has been depleted due to domestication and modern breeding. Wild relatives are a valuable source for improving drought tolerance in domesticated wheat. A QTL region on chromosome 2BS of wild emmer wheat (Triticum turgidum ssp. dicoccoides), conferring high grain yield under well-watered and water-limited conditions, was transferred to the elite durum wheat cultivar Uzan (T. turgidum ssp. durum) by a marker-assisted backcross breeding approach. The 2B introgression line turned out to be higher yielding but also exhibited negative traits that likely result from trans-, cis-, or linkage drag effects from the wild emmer parent. In this study, the respective 2BS QTL was subjected to fine-mapping, and a set of 17 homozygote recombinants were phenotyped at BC4F5 generation under water-limited and well-watered conditions at an experimental farm in Israel and at a high-throughput phenotyping platform (LemnaTec-129) in Germany. In general, both experimental setups allowed the identification of sub-QTL intervals related to culm length, kernel number, thousand kernel weight, and harvest index. Sub-QTLs for kernel number and harvest index were detected specifically under either drought stress or well-watered conditions, while QTLs for culm length and thousand-kernel weight were detected in both conditions. Although no direct QTL for grain yield was identified, plants with the sub-QTL for kernel number showed a higher grain yield than the recurrent durum cultivar Uzan under well-watered and mild drought stress conditions. We, therefore, suggest that this sub-QTL might be of interest for future breeding purposes.

The wild emmer wheat grain protein content 5B QTL introgressed into bread wheat is associated with tolerance to nitrogen deficiency .

“…This enabled us to select BC 3 F 4 IL99 (further designated as IL99) as a parent for development of a large ne mapping population, carrying the shortest introgression size and lower level of heterozygosity at the whole-genome level. IL99 was backcrossed as the female parent with Ruta to produce the BC 4 F 1 population which was increased to BC 4 F 4 following genotyping in each generation, as previously described (Deblieck et al 2022). For the ne-mapping procedure, we rst used the KASP markers that had been used for MAS and then saturated the QTL region with additional KASP markers obtained by genotyping the parental lines.…”

Nitrogen deficiency tolerance conferred by introgression of a QTL derived from wild emmer into bread wheat

“…This enabled us to select IL99-2 (further designated as IL99) as a parent for the development of a large fine mapping population. IL99 was backcrossed again as the female parent with Ruta to produce the BC 4 F 1 population which was increased to BC 4 F 4 following genotyping in each generation , as previously described (Deblieck et al 2022 ). For the fine mapping procedure, we first used the KASP markers that had been used for MAS and then saturated the QTL region with additional KASP markers obtained by genotyping the parental lines.…”