Evalution of slow rusting resistance to stem rust (Puccinia graminis f. sp. tritici) in some elite wheat lines

The emergence and rapid spread of virulent races of wheat rusts has driven a search for sources of resistance for durable resistance. Slow rusting resistance, a kind of race-nonspecific resistance, has been reported to be more durable. In this study in order to identify possible sources of durable stem rust resistance between elite wheat lines, slow rusting parameters including coefficient of infection (CI), final rust severity (FRS), apparent infection rate (r) and relative area under disease progress curve (rAUDPC) were evaluated in a set of forty six wheat lines along with susceptible control (mixture of McNair and the line CD-90-12) in 2015-2016 and 2016-2017 cropping seasons. This study was conducted in field plots at Ardabil Agricultural Research Station (Iran). All lines were evaluated under natural infection conditions against race population having virulence to resistance genes including Sr25, Sr5, Sr6, Sr7a, Sr23, Sr28, Sr29, Sr30, Sr33, Sr34, Sr37, SrDP2, SrGT, SrPL, SrWLD, SrH and SrTmp < /em>. Results of evaluations for resistance parameters showed that the lines M-93-13, M-93-14, M-93-16 and M-93-20 had low level of CI, FRS, r and rAUDPC so were considered as lines having high levels of slow rusting resistance. The lines C-93-10, C-94-6, C-94-8, CD-94-6, M-93-3, M-93-12 and M-93-18 had moderate level of slow rusting and 25 lines with high values of CI, FRS, r and rAUDPC were grouped as lines having low level of slow rusting resistance. The remaining lines without slow rusting resistance were considered as susceptible group. The lines with high and moderate levels of slow rusting resistance can be used in breeding programs or releasing new resistant cultivars.