|Kolmer, James - Jim|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2007
Publication Date: 7/1/2007
Citation: Olivera, P.D., Steffenson, B.J., Anikster, Y., Kolmer, J.A. 2007. Resistance of Sharon Goatgrass (Aegilops sharonensis) to Fungal Diseases of Wheat. Plant Disease. 91:942-950.
Interpretive Summary: Sharon goatgrass is found in Israel and is a plant related to wheat. This wild relative of wheat has resistance to many important diseases that attack wheat in the U.S. and world-wide. Collections of goatgrass from Israel were tested for resistance to different fungal pathogens that also attack wheat. Resistance to leaf rust, stem rust, Fusarium, powdery mildew, and tan spot was found in the goatgrass collections. The goatgrass collections have the potential to be used in wheat breeding programs as sources of new disease resistance genes.
Technical Abstract: Sharon goatgrass (Aegilops sharonensis) is a wild relative of wheat that is native to Israel and Lebanon. The importance of Ae. sharonensis as a source of new resistance genes for wheat warrants additional research on the characterization of accessions for economically important genes. Thus, the objectives of this study were to evaluate a collection of Ae. sharonensis accessions for resistance to seven important fungal diseases of wheat and assess the phenotypic diversity of the germplasm for disease reaction. The frequency of resistance in Ae. sharonensis was highest to powdery mildew (79-83%) and leaf rust (60-77%). Resistance to stem rust also was common, although the percentage of resistant accessions varied markedly depending on the pathogen race—from 13% to race TTTT to 72% to race QCCJ. The frequency of resistance was intermediate to stripe rust (45%) and low to tan spot (15-29%) and spot blotch (0-34%). None of the Ae. sharonensis accessions was resistant to Fusarium head blight. Many of the accessions tested exhibited heterogeneous reactions (i.e. had both resistant and susceptible plants) to one or more of the diseases, suggesting that heterozygosity may be present at some resistance loci. Substantial variation was observed in the level of diversity to individual diseases as Shannon’s Equitability index ranged from 0.116 (for Fusarium head blight) to 0.994 (for tan spot). A high level of diversity was found both between and within collection sites. Moreover, differences in the geographic distribution of resistant accessions were observed. For example, accessions from northern Israel were generally less diverse and less resistant to leaf rust and stripe rust than accessions from more southern locations. Four Ae. sharonensis accessions were highly resistant to most of the diseases evaluated and may provide a source of unique resistance genes for introgression into cultivated wheat.