Patterns of resistance of Israeli wild emmer wheat to pathogens I. Predictive method by ecology and allozyme genotypes for powdery mildew and leaf rust

Abstract

The association of ecological factors and allozyme markers with genotypes of tetraploid wild emmer wheat, Triticum dicoccoides, varying in resistance to four cultures of the pathogen Ervsiphe graminis tritici, and to one culture of Puccinia recondita tritici, which incite the diseases powdery mildew and leaf rust respectively, were explored theoretically and practically. The study involved 233 accessions comprising 10 populations representing the ecological range of 7". diococcoides in Israel. Our results indicate that genetic polymorphism for resistance to both pathogens is structured geographically, and is predictable by climatic as well as allozymic markers. Three variable combinations of water factors and temperature differentials significantly explain 0.27 and 0.14 of the spatial variance for resistance to powdery mildew and leaf rust, respectively, suggesting the involvement of natural selection. Several allozyme g~notypes, singly, or in combination, are significantly associated with disease resistance. We conclude that T. dicoccoides populations in Israel, which grow in the center of diversity of the species, contain large amounts of unexploited disease resistant genotypes. The populations could be effectively screened and utilized for producing resistant cultivars by means of ecological factors and allozyme markers as predictive guidelines.

Resources of high-protein genotypes in wild wheat,Triticum dicoccoides in Israel: Predictive method by ecology and allozyme markers

“…Enzyme marker genes are ideal candidates for such a study as we have shown already in our own work on powdery mildew in wild barley (Nevo et al, 1984a), and on powdery mildew, leaf rust, stripe rust and agronomic elite characters in wild emmer (Nevo et al, 1984b(Nevo et al, , 1985a. In the present study we have shown that protein percentage, kernel weight and protein weight (--protein percentage • kernel weight) in wild emmer are associated with allozyme genotype markers singly or in combinations.…”

Molecular Genetic Maps in Wild Emmer Wheat, Triticum dicoccoides: Genome-Wide Coverage, Massive Negative Interference, and Putative Quasi-Linkage

“…Wild emmer wheat is an important genetic resource that could be exploited in breeding for resistance to a broad range of diseases, pests, and for tolerance to poor soil and climatic factors (Nevo 1983(Nevo , 1989(Nevo , 1995. Among many agriculturally important characteristics already found in T. dicoccoides is its resistance to stripe rust (Gerechter-Amitai and Stubbs 1970;Nevo et al 1986;Fahima et al 1998), stem rust (Nevo et al 1991), and powdery mildew (Nevo et al 1985). Wild emmer wheat contains rich and variable genetic resources that will play a major role in future wheat improvement (Nevo 1983(Nevo ,1989(Nevo , 1995.…”

Genetic Markers and Plant Genetic Resource Management

“…Consequently, such associations are expected to occur more frequently in clones than in sexually reproducing germplasm, and in inbreeding populations more frequently than in outbreeding populations. Indeed, several recently reported examples of genetic marker-facilitated utilization involve highly autogamous or clonally propagated crops (Nevo et al 1984(Nevo et al , 1985Weeden et al 1984;Zhang and Tang 1987;Martin et al 1991). Nevertheless, genetic markers are not effective in this role in every clonal or inbreeding species (e.g., Burdon and Jarosz 1989).…”