Quantitative resistance of some Elite wheat lines to Puccinia striiformis f. sp. tritici

Abstract

Host resistance is the most economical way to manage wheat stripe rust caused by Puccinia striiformis f. sp. tritici. Slow rusting, a type of quantitative resistance, has been reported to last for a long time. Quantitative resistance, in terms of slow rusting parameters including final rust severity (FRS), apparent infection rate (r), relative area under disease progress curve (rAUDPC) and coefficient of infection (CI), was evaluated in a set of 29 wheat genotypes along with susceptible control during 2008–2009 and 2009–2010 cropping seasons. This study was conducted in field plots at Ardabil Agricultural Research Station (Iran) under natural infection conditions with two times artificial inoculation. Artificial inoculation was carried out by yellow rust inoculum having virulent genes against Yr2, Yr6, Yr7, Yr9, Yr22, Yr23, Yr24, Yr25, Yr26, Yr27, YrA and YrSU. Results of mean comparison for resistance parameters showed that lines C-86-1, C-86-2, C-87-1 and C-87-3 along with susceptible had the highest values of FRS, CI, r and rAUDPC, therefore were selected as susceptible lines. The lines C-86-3, C-86-9, C-87-2, C-87-6, C-87-8, C-87-11 and C-87-18 were susceptible at the seedling stage and had low level infection at adult plant stage. Consequently, these lines with low different parameters most probably have slow rusting resistance. The remaining lines had no infection or were at low level of infection. Thus, they were selected as resistant or moderately resistant lines. In this study, correlation coefficient between different parameters of slow rusting was significantly high (r = 0.92–0.99).