Investigation of Aegilops umbellulata for stripe rust resistance, heading date, and the contents of iron, zinc, and gluten protein

Aegilops umbellulata (UU) is a wheat wild relative that has potential use in the genetic improvement of wheat. In this study, 46 Ae. umbellulata accessions were investigated for stripe rust resistance, heading date (HD), and the contents of iron (Fe), zinc (Zn), and seed gluten proteins. Forty-two of the accessions were classified as resistant to stripe rust, while the other four accessions were classified as susceptible to stripe rust in four environments. The average HD of Ae. umbellulata was significantly longer than that of three common wheat cultivars (180.9 d vs. 137.0 d), with the exception of PI226500 (138.9 d). The Ae. umbellulata accessions also showed high variability in Fe (69.74-348.09 mg kg-1) and Zn (49.83-101.65 mg kg-1) contents. Three accessions (viz., PI542362, PI542363, and PI554399) showed relatively higher Fe (230.96-348.09 mg kg-1) and Zn (92.46-101.65 mg kg-1) contents than the others. The Fe content of Ae. umbellulata was similar to those of Ae. comosa and Ae. markgrafii but higher than those of Ae. tauschii and common wheat. Aegilops umbellulata showed a higher Zn content than Ae. tauschii, Ae. comosa, and common wheat, but a lower content than Ae. markgrafii. Furthermore, Ae. umbellulata had the highest proportion of gamma-gliadin among all the species investigated (Ae. umbellulata vs. other species=mean 72.11% vs. 49.37%; range: 55.33-86.99% vs. 29.60-67.91%). These results demonstrated that Ae. umbellulata exhibits great diversity in the investigated traits, so it can provide a potential gene pool for the genetic improvement of these traits in wheat.