Mapping Yr28 and other genes for resistance to stripe rust in wheat

Singh, R.P.; Nelson, J.C.; Sorrells, M.E.

Mapping Yr28 and other genes for resistance to stripe rust in wheat

2000

Singh, R.P. | Nelson, J.C. | Sorrells, M.E.

Stripe (yellow) rust, caused by Puccinia striiformis West., is an important constraint to wheat production in cool environments. With the purpose of identifying genes for resistance to the disease, a RFLP mapping population of recombinant inbred lines developed from a synthetic [Triticum turgidum L. × Aegilops tauschii (Coss.) Schmal.] × T. aestivum L. cv. `Opata 85' cross was visually evaluated for seedling infection type in three greenhouse inoculation tests and for adult-plant disease severity in four field tests at Celaya and Toluca, Mexico. A previously unidentified gene from Ae. tauschii, designated as Yr28, was located on chromosome arm 4DS. Although Yr28 strongly influenced seedling resistance, it showed a strong effect in adult plants at only the warmer of the two field sites. A second gene showed high environmental sensitivity in seedling tests, with resistance associated with Opata marker alleles near the adult-plant resistance (APR) gene Yr18 on chromosome arm 7DS. Gene Yr18, known to be present in Opata, strongly reduced disease response in field trials and was tightly linked with leaf-rust resistance gene Lr34 Three other regions from Opata on chromosome arms 3BS, 3DS, and 5DS were also associated with APR.

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