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Meeting the Challenge of Yellow Rust in Cereal Crops - ICARDA

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360<br />

Identification <strong>of</strong> wheat<br />

germplasm with effective yellow<br />

rust resistance genes<br />

A. Kokhmetova 1 and Sh. Rsaliev 2<br />

1. Institute <strong>of</strong> Plant Biology and Biotechnology, Almaty, Kazakhstan<br />

2. Institute <strong>of</strong> Problems <strong>of</strong> Biological Safety, Gvardeysky, Kazakhstan<br />

Abstract<br />

<strong>Yellow</strong> or stripe rust <strong>of</strong> wheat (Pucc<strong>in</strong>ia striiformis f.sp. tritici) causes severe<br />

damage to wheat production throughout <strong>the</strong> world, <strong>in</strong>clud<strong>in</strong>g Central Asia.<br />

Dur<strong>in</strong>g <strong>the</strong> epidemic <strong>of</strong> 2009 <strong>in</strong> Kazakhstan, most high yield<strong>in</strong>g widely grown<br />

cultivars were severely attacked by stripe rust. Effectiveness <strong>of</strong> most known Yr<br />

genes broke down due to changes <strong>in</strong> virulence <strong>of</strong> <strong>the</strong> pathogen. This study<br />

aimed to identify new wheat germplasm resistant to yellow rust, us<strong>in</strong>g<br />

greenhouse and field tests. Seedl<strong>in</strong>gs <strong>of</strong> w<strong>in</strong>ter wheat recomb<strong>in</strong>ant <strong>in</strong>bred l<strong>in</strong>es<br />

(RILs) and parental cultivars were tested under controlled greenhouse<br />

conditions aga<strong>in</strong>st two races <strong>of</strong> P. striiformis f.sp. tritici prevalent <strong>in</strong><br />

Kazakhstan: 27E9 and 47E159. The IT data <strong>of</strong> seedl<strong>in</strong>g reactions were scored.<br />

Genetic analysis based on <strong>the</strong> reaction data <strong>of</strong> RILs to <strong>in</strong>fection was used for<br />

identify<strong>in</strong>g <strong>the</strong> genes for resistance. Observed and expected data were<br />

analysed us<strong>in</strong>g <strong>the</strong> Chi-squared test. The results <strong>of</strong> field evaluation <strong>of</strong> wheat<br />

isogenic l<strong>in</strong>es and yellow rust differentials <strong>in</strong> Almalybak (Almaty oblast)<br />

<strong>in</strong>dicated that <strong>the</strong> most effective genes aga<strong>in</strong>st stripe rust were Yr5, Yr10, Yr15<br />

and Yr24. In comparison with 2006 and 2007 data, most <strong>of</strong> <strong>the</strong> l<strong>in</strong>es and<br />

cultivars carry<strong>in</strong>g genes for resistance to yellow rust expressed <strong>in</strong>creased<br />

susceptibility to <strong>the</strong> disease <strong>in</strong> 2009. The predom<strong>in</strong>ant pathotypes <strong>in</strong> <strong>the</strong><br />

population <strong>of</strong> P. striiformis f.sp. tritici are <strong>the</strong> races virulent to <strong>the</strong>se genes. A<br />

total <strong>of</strong> 11 pathotypes <strong>of</strong> rust were identified as <strong>the</strong> most virulent from <strong>the</strong><br />

yellow rust samples. The pathotypes 47E223, 15E191, 47E159, 71 191, 71E175,<br />

111E155 and 111E158 were virulent on cultivars Vilmor<strong>in</strong> 23, He<strong>in</strong>es Kolben,<br />

Lee, Ch<strong>in</strong>ese 166, He<strong>in</strong>es VII, Compair, Nord Desprez, He<strong>in</strong>es Peko,<br />

Reichersberg 42 and Hybrid 46. Pathotype 31E158 was virulent on Moro (Yr10,<br />

YrMor) and pathotype 47E223 on Spald<strong>in</strong>gs Prolific (Yr6, YrSP). All pathotypes<br />

studied were virulent on <strong>the</strong> cultivars He<strong>in</strong>es Kolben, Lee, Ch<strong>in</strong>ese 166,<br />

He<strong>in</strong>es VII and Reichersberg 42. Among <strong>the</strong> differentials, Spald<strong>in</strong>gs Prolific<br />

had immunity to <strong>the</strong> most isolates. He<strong>in</strong>es Kolben (Yr6) had a susceptible<br />

reaction to almost all isolates. Cv. Moro was resistant to <strong>the</strong> majority <strong>of</strong> <strong>the</strong><br />

isolates. The evaluation <strong>of</strong> field response to yellow rust <strong>in</strong> commercial cultivars<br />

and advanced l<strong>in</strong>es <strong>of</strong> wheat showed that dur<strong>in</strong>g <strong>the</strong> epidemic <strong>of</strong> 2009, most

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