Inheritance of Stripe Rust Resistance among Near-Isogenic Lines of Spring Wheat
- C. A. Griffey and
- R. E. Allan
Increased range of virulence of stripe rust (Puccinia striiformis West.) on wheat (Triticum aestivum L.) in the northwestern USA has required assemblage of a broad genetic base of resistance. This study genetically differentiated among 14 sources of stripe rust resistance represented by near-isogenic lines developed in stripe rustsusceptible ‘Lemhi 53.’ Plant reactions of the lines were evaluated in F1, F2, and BC1 populations from resistant by susceptible crosses and in F1 and F2 populations from resistant by resistant crosses. Greenhouse-grown seedlings and field-grown adult plants were tested for their reactions to the fungus. Most lines had resistance believed to be race-specific, and the same gene(s) probably governed both their seedling and adult-plant reactions. Other lines expressed only adult-plant resistance, and some may have had different genes for each type of resistance. Segregation patterns from resistant by susceptible parent crosses suggested monogenic or digenic control of plant reaction to the fungus with digenic expression more common in the field. Some lines with resistance from ‘Brevor’ and ‘Alba’ and other lines with resistance from Alba, ‘Webster’, ‘Giza 139’/‘Gabo’ and ‘Ministre’ probably had gene(s) in common for reaction to the fungus. Some lines derived from Webster, Giza 139/Gabo, and ‘Soissonais’ had gene(s) in common for their adult-plant reactions. The cross ‘Magnif 27’/5*Lemhi 53/3/T. spelta/‘Coastal’//6*Lemhi 53 expressed novel seedling resistance; wherein the F~ progeny derived from susceptible parents expressed digenic control of resistance. Genetic diversity was modest among the various lines, especially for seedling resistance.
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