Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/31/1998
Publication Date: N/A
Citation: BROWN GUEDIRA,G.L., COX,T.S., BOCKUS,W.W., GILL,B.S., SEARS,R.G., REGISTRATION OF KS96WGRC38 AND KS96WGRC39 TAN SPOT-RESISTANT HARD RED WINTER WHEAT GERMPLASMS, CROP SCIENCE, 1998. Interpretive Summary: The disease tan spot of wheat is capable of causing large losses of yield to wheat when infection is heavy. In order to develop resistant hard winter wheat cultivars, wheat breeders need to have access to new resistance genes in agronomically adapted backgrounds. Many strains of the wild relatives of wheat have genes for resistance to various diseases of wheat. We used two tan spot-resistant strains of the wild relatives, Aegilops tauschii and Triticum timopheevii subsp. aremeniacum, to pollinate susceptible hard winter wheat cultivars. We then used backcrossing to transfer two new genes for resistance to tan spot into germplasm lines KS96WGRC38 and KS96WGRC39. These genes should be useful to wheat breeders who are developing tan spot-resistant cultivars.
Technical Abstract: New genes for resistance to tan spot [caused by Pyrenophora tritici-repentis (Died.) Drechs] in agronomically adapted backgrounds are needed in the hard winter wheat region. KS96WGRC38 and KS96WGRC39 are hard red winter wheat germplasms resistant to tan spot. KS96WGRC38 is a BC2F3-derived line with the pedigree KS90WGRC10*3/TA 895. The donor parent, TA 895, is a tan spot-resistant accession of Triticum timopheevii subsp. armeniacum from northern Iraq. KS96WGRC39 is a BC2F3-derived line with the pedigree TAM 107*3/TA 2460. TA 2460 is an accession of Aegilops tauschii Coss. with resistance to leaf rust (Lr41) and tan spot. Both resistances were transferred from TA 2460 to KS96WGRC39. In replicated tests at the seedling stage in the greenhouse, KS96WGRC38 and KS96WGRC39 averaged 27.6% and 25.3%, respectively, of leaf area affected by tan spot. This was similar to the level for infection observed in the test on the tan spot-resistant cultivar 'Jagger' that had 25.1% diseased leaf area. Tan spot resistances in the two germplasms are not conditioned by the same genetic loci, because the donor species do not have a common genome.