Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2002
Publication Date: 4/30/2004
Citation: Brown Guedira, G.L., Fritz, A.K., Gill, B.S., Singh, S., Cox, T.S. 2004. Registration of ks00wgrc44 leaf rust-resistant hard red winter wheat germplasm. Crop Science. 44:702. Interpretive Summary: Leaf rust is one of the most important foliar diseases of wheat world-wide. Yield losses in the U.S. Great Plains have averaged $150 million dollars annually since 1990. Genetic resistance is the most effective method of control of leaf rust. New genes for resistance to leaf rust are continually needed as new races of the pathogen evolve that are able to overcome currently deployed sources of resistance. Wild wheat relatives are a valuable source of new leaf rust resistance genes. A hard red winter germplasm, KS00WGRC44, was developed that has a new leaf rust resistance gene transferred from wild goatgrass (Ae. tauschii). KS00WGRC44 is resistant to 20 diverse races of leaf rust. No disease was observed on KSOOWGRC44 when evaluated in field plots at Manhattan and Hutchinson, KS and at Uvalde and Beaumont, Texas. This germplasm is similar to the susceptible recipient wheat variety TAM 107 for all traits except leaf rust resistance. Leaf rust resistance in KS00WGRC44 is due to a single dominant gene from TA 1715 of Ae. tauschii. This germplasm can be used by wheat breeders for development of leaf rust resistant wheat varieties.
Technical Abstract: KS00WGRC44 is a BC2 F5-derived line with the pedigree `TAM 107'*3/TA 1715. TAM 107 is a hard red winter wheat cultivar, and TA 1715 is a leaf rust resistant accession of Aegilops tauschii Coss. collected in Iran. Seedlings of KS00WGRC44 exhibited a low infection type [IT = 1 or lower on a scale of 0 to 4 (1)] when inoculated with 20 races or isolates of leaf rust (Puccinia triticina Eriks). High infection types were observed on seedlings of TAM 107 with all races of leaf rust tested. Adult plants of KS00WGRC44 displayed a low infection type (;) when exposed to moderate to heavy leaf rust inoculum levels in the field at Manhattan and Hutchinson, Kansas in 1999 and 2000, and under heavy inoculum pressure at Uvalde and Beaumont, Texas in 2000. Except for resistance to leaf rust, KS00WGRC44 is similar to TAM 107 in height, heading date, and overall phenotype.Leaf rust resistance in KS00WGRC44 is due to a single dominant gene from TA 1715. Differences in infection type of seedlings when inoculated with diverse isolates of Puccinia triticina indicate that the gene in KS00WGRC44 is different from the Ae. tauschii-derived genes Lr32, Lr39, Lr41 and Lr42. KS00WGRC44 had a lower infection type (IT = ;1) when inoculated with leaf rust race PNM-10,18 at the seedling stage than that observed on the lines TA 4186 (Lr39; IT = 4) and KS90WGRC10 (Lr41; IT = 3C). When seedlings of KS00WGRC44 and RL5713 (Lr32) were inoculated with the TFG-10 race of leaf rust, IT of 0 and 2+ were observed, respectively. When inoculated with race KDB-10, seedlings of KS91WGRC11 (Lr42) had an IT of 2C while no sporulation was observed on seedlings of KS00WGRC44 (IT = ;). Absence of the 1.36 Kb fragment amplified by the primer pair KSUD14, which corresponds to a portion of the cloned Lr21 gene, indicates that the gene in KS00WGRC44 is different from Lr21 (3).