Stem rust is a major threat to wheat production in Georgia. Breeding for resistance to the rusts is a major strategy for wheat improvement programs. Our objective was determination of the stem rust resistance levels in entries of the 4nd International Winter Wheat Stem Rust Resistance Nursery. Responses of 85 varieties/lines were evaluated in an inoculated field nursery. A coefficient of infection (CI) and area under the disease progress curve (AUDPC) were estimated for each entry. Fifteen entries (T03/17, TAM-107/T21, SD92107-2/SD99W042, KS95U522/TX95VA0011/F1/JAGGER, AR800-1-3-1/NW97S320, FL9547/NC00-14622, FL9547/TX00D1626, TAM302/KS93U450, MCCORMİCK/TREGO, NC00-14622/2137, TAM200/KAUZ//GOLDMARK/3/BETTY, KS920709-B-5-1-1/BURBOT-4, AFINA SOMNEZ, TAM200/KAUZ/4/BEZ/NAD//KZM(ES85.24/3/F900K) were resistant; 39 showed moderate resistance; 15 were scored MR-MS and 17 were moderately susceptible. Most of entries had very low CI (0.2 - 0.5) and AUPDC (less than 10.0); the best including T07/08, T07/09, T08/02, T08/01, T08/02, T08/04, CAKET/PEHLIVAN, ID800994.W/VEE//PIOPIO/3/MNCH/4/FDL4/KAUZ, PBI1013.13.3/3233.35 /3/STAR//KAUZ/STAR, DULGER-1//VORONA/BAU, ZANDER-17/3/YE2453/KA//1D13.1/MLT, 55-1744/7C//SU/RDL/3/CROW/4/MILAN/5/ITOR, 1D13.1/MLT//TUI/3/S?NMEZ/4/ATAY/GALVEZ87, TAM107//ATAY/GALVEZ87, HBF0290/X84W063-9-39-2//ARH/3/LE2301, STAR/BWD/3/PRL/VEE#6//CLMS, FRTL//AGRI/NAC/3/KALYOZ-17, CV. RODİNA/AE.SPELTOİDES10 KR, TAM 107//ATAY/ GALVEZ87, and 06393GP1. The severities for susceptible entries varied from 20 to 70%, with checks Morocco and Bezostaya 1 at 80% and 60%, respectively. However, the majority of entries (94%) had average CI of 0.2 - 20 and five entries with CI 21 - 40 had high to moderate levels of resistance.
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Stripe rust is a worldwide constraint to wheat production. The rust pathogens are assumed to have originated in the Caucasus, from which they disseminated into Western Europe and Asia (Zhukovsky 1965, Euphytica, 14; Stubbs 1985, The Cereal Rusts II). Rust surveys are a useful means to provide information on distribution. More than 400 wheat fields were monitored for rust incidence and severity and for collection of samples at 20 locations in Georgia during 2010-2013. The majority of wheat fields were occupied by Russian cultivars and Bezostaya-1 was the most common, followed by Copper and American cv. Jagger. Yellow rust was the most widely distributed rust, with>65% of fields showing its presence. In 2009 yellow rust incidence was moderate to high. Abundant overwintering inoculum, susceptible cultivars and favorable conditions resulted in severe epidemics in late May and early June 2010. Mean field incidence and severities were 74.8 and 84.6% in the Kakheti zone, and 70 and 68.2% in Kvemo Kartli. Incidence was lower in the following years due to drought and high late spring temperatures. Bezostaya 1 and Jagger showed moderately susceptible reactions to all three rust, but Copper was moderately resistant. Accessions of Georgian endemic species T. carthlicum, T. timopheevi, T. macha, T. georgicum and T. monococcum were resistant to all three rusts.