Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2004
Publication Date: 3/1/2005
Citation: Anikster, Y., Manisterski, J., Long, D.L., Leonard, K.J. 2005. Resistance to leaf rust, stripe rust, and stem rust in Aegilops species in Israel. Plant Disease. 89:303-308. Interpretive Summary: Leaf rust is one of the most serious diseases of wheat in the U.S. and worldwide. The most effective and economical way to control leaf rust is through the development of resistant wheat varieties. Unfortunately, most resistance to leaf rust is only effective against some races of the leaf rust fungus. Such resistance usually remains effective for only a few years because new rust races arise that are not affected by the resistance. The available supply of rust resistance genes in cultivated wheat varieties and breeding lines is nearly exhausted. We collected seed from 1,323 plants of wild wheat relatives in the genus Aegilops from natural habitats in Israel and tested the Aegilops lines for resistance to leaf rust, stripe rust, and stem rust in Israel and the U.S. Nearly all lines of Aegilops speltoides, a close relative of bread wheat, were resistant to all three rusts. Many lines of Aegilops longissima, Aegilops sharonensis, and Aegilops variabilis also were resistant to wheat leaf rust. These lines can be crossed to cultivated wheat varieties and may provide combinations of resistance genes with long-lasting protection against leaf rust in U.S. wheat production. This would prevent wheat leaf epidemics that periodically reduce yields by 15% or more in major wheat-producing States in the U.S.
Technical Abstract: A total of 1,323 single plant accessions of Aegilops bicornis, Ae. kotschyi, Ae. longissima, Ae. ovata, Ae. searsii, Ae. sharonensis, Ae. speltoides, and Ae. variabilis collected from 18 regions in Israel and adjacent regions of Lebanon and Egypt were evaluated for leaf rust and stripe rust resistance in field plots and for seedling resistance to leaf rust and stem rust in greenhouse tests. Nearly all accessions of Ae. speltoides were highly resistant to leaf rust, stripe rust, and stem rust. Ae. longissima and Ae. ovata were highly resistant to stripe rust, but Ae. bicornis and Ae. kotschyi were highly susceptible. Ae. searsii was highly susceptible to stem rust, but 24-51% of accessions of Ae. bicornis, Ae. longissima, Ae. ovata, and Ae. variabilis were resistant. Except for Ae. ovata and Ae. speltoides, more than 95% of the Aegilops accessions were susceptible to leaf rust caused by Puccinia recondita alternating on Anchusa. Only Ae. ovata was susceptible to P. recondita from Echium. In field tests, Ae. bicornis showed high susceptibility to common wheat leaf rust, caused by P. triticina, but more than 90% of the accessions of the other Aegilops spp. developed little or no leaf rust on adult plants. Ae. bicornis, Ae. koschyi, and Ae. searsii were highly susceptible as seedlings to P. triticina. Most accessions of Ae. variabilis and about half the accessions of Ae. longissima had good seedling resistance to P. triticina. Few accessions of Ae. ovata showed seedling resistance to the P. triticina population in Israel, but 30% were resistant to U.S. isolates. The Aegilop spp. in Israel and adjoining countries provide a rich and varied source of rust resistance for wheat breeding.