Evaluation of grain dormancy under field conditions in a wheat (Triticum aestivum) qsd1 triple mutant

Abstract

Genome editing is a powerful tool for improving the agronomic traits of polyploid crops such as wheat (Triticum aestivum) by simultaneously generating mutations in multiple homoeologs. However, improvements in cultivars that are amenable to transformation (and thus genome editing) must be tested in region‐specific cultivars under field conditions. Grain dormancy helps ensure the appropriate timing of germination and strong dormancy helps prevent preharvest sprouting. We previously introduced mutations in all three homoeologs of quantitative trait locus for seed dormancy1 (Qsd1) in the wheat cultivar Fielder using genome editing and showed that this triple qsd1 mutant had strengthened grain dormancy under laboratory conditions. In this study, we introduced the triple qsd1 mutation into two Japanese cultivars, Tamaizumi and Tamaizumi R, by recurrent backcrossing. As in Fielder, the triple qsd1 mutation also altered grain dormancy in the Tamaizumi and Tamaizumi R genetic backgrounds under laboratory conditions. To evaluate the mutation's effect on grain dormancy in the field, we conducted field trials in two areas in Japan and assessed the dormancy of the harvested grains. This is the first report of field trials of genome‐edited wheat in Japan. Our findings demonstrate the importance of such trials for evaluating grain dormancy, which is influenced by environmental conditions.