Email: seragalnor.yasir.5x@kyoto-u.ac.jp

Introducing genes from wild relatives is one of the best options to broaden the narrow genetic diversity and discover new alleles necessary for wheat improvement under the pressures of climate change and the growing world population. Among wheat wild relatives, Aegilops tauschii is believed to be an attractive and rich gene source; therefore, we developed a new strategy for fast and efficient utilization of Ae. tauschii genetic diversity for wheat breeding.

A total of 43 primary synthetic hexaploid wheat (SHW) lines were developed by crossing the durum wheat cultivar ʻLangdonʼ with 43 different Ae. tauschii accessions representing the entire range of the species. A multiple synthetic derivatives (MSD) population was then developed by crossing and backcrossing the hexploid wheat ʻNorin 61ʼ with the 43 SWH lines. We genotyped selected lines, identified their pedigree and evaluated them across six heat-stress environments (combination of seasons and locations) in Sudan. In addition, the harvested seeds were used to examine some end-use quality attributes.

The MSD lines showed wide variation in the trait studied. Some MSD lines were superior to the adapted Sudanese cultivars and the recurrent parent ‘Norin 61’ in heat stress tolerance and end-use quality. Genome wide association analysis showed several potential marker-trait associations (alleles) that could enhance heat stress tolerance and end-use quality under heat stress conditions. For seed dormancy we followed a different strategy. First, we screened 3000 seeds from the MSD mixture, selected the dormant lines, genotyped them and identified their pedigree.

Using the pedigree information a backcross inbred lines population was constructed (BC1F6), genotyped, and evaluated for seed dormancy. QTL analysis revealed a novel QTL on chromosome 5D that might correspond to a putative alanine transferase gene. Our findings demonstrate that our strategy was efficient and successful in exploring the diversity of Ae. tasuchii in the background of bread wheat.

This work represents a rare example of systematic evaluation of wild relatives' genes in a hexaploid wheat genetic background, and it may pave the way for obtaining more useful insights that could contribute to food security. We could successfully move Ae. tauschii genes from the gene bank to the field and make them available for selection.