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

Mathieu Deblieck; Gergely Szilagyi; Fatiukha Andrii; Yehoshua Saranga; Madita Lauterberg; Kerstin Neumann; Tamar Krugman; Dragan Perovic; Klaus Pillen; Frank Ordon

doi:10.3389/fgene.2022.955295

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

Front Genet. 2022 Oct 19:13:955295. doi: 10.3389/fgene.2022.955295. eCollection 2022.

Authors

Affiliations

¹ Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Quedlinburg, Germany.
² The Hebrew University of Jerusalem, Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel.
³ University of Haifa, Institute of Evolution, Haifa, Israel.
⁴ Research Group Genebank Documentation, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany.
⁵ Department of Plant Breeding, Martin-Luther-University Halle-Wittenberg, Institute of Agricultural and Nutritional Sciences, Halle, Germany.

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.

Keywords: 15K-iSelect; GBS; culm length; drought tolerance; grain yield; kernel number; wild emmer.