Stem rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks ＆ E. Henn., is an important disease of wheat （Triticum aestivum L.） in many countries. To estimate grain yield losses due race Ug99 （TTKSK）, repli...Stem rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks ＆ E. Henn., is an important disease of wheat （Triticum aestivum L.） in many countries. To estimate grain yield losses due race Ug99 （TTKSK）, replicated experiments including fifteen wheat cultivars were screened for seedling and adult plant resistance. Greenhouse seedling test was conducted under controlled conditions. Field experiments were set up at two locations, Mau-Narok and KARI-Njoro, during 2008 and 2009 cropping seasons. The stem rust epidemics were created by inoculating spreader rows of a susceptible variety planted perpendicular to rows of non-protected plots. Rust severity and infection response were determined using modified Cobb scale. All the cultivars were susceptible at seedling stage, but some displayed adult plant resistance response despite of the high disease pressure. Mean grain yield losses ranged between 5.6% and 66.3% and were highly correlated to final disease severity （FDS） and the area under disease progress curve （AUDPC）. Genetic studies are needed to characterise the adult plant resistance in tolerant culti（,ars to race Ug99 for exploitation in breeding for resistance.展开更多
文摘Stem rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks ＆ E. Henn., is an important disease of wheat （Triticum aestivum L.） in many countries. To estimate grain yield losses due race Ug99 （TTKSK）, replicated experiments including fifteen wheat cultivars were screened for seedling and adult plant resistance. Greenhouse seedling test was conducted under controlled conditions. Field experiments were set up at two locations, Mau-Narok and KARI-Njoro, during 2008 and 2009 cropping seasons. The stem rust epidemics were created by inoculating spreader rows of a susceptible variety planted perpendicular to rows of non-protected plots. Rust severity and infection response were determined using modified Cobb scale. All the cultivars were susceptible at seedling stage, but some displayed adult plant resistance response despite of the high disease pressure. Mean grain yield losses ranged between 5.6% and 66.3% and were highly correlated to final disease severity （FDS） and the area under disease progress curve （AUDPC）. Genetic studies are needed to characterise the adult plant resistance in tolerant culti（,ars to race Ug99 for exploitation in breeding for resistance.
