Adult plant resistance to leaf and stripe rusts in landraces

A set of 63 wheat landraces obtained from Institute of Agri-Biotechnology and Genetic Resources, NARC-Islamabad was screened for adult plant resistance (APR) at two inoculated locations during the 2012-13 cropping season, i.e. Wheat Research Institute (WRI), Faisalabad, for leaf rust and Cereal Crops Research Institute (CCRI), Pirsabak, for stripe rust. Responses based on coefficients of infection (CI) were recorded. Five landraces were susceptible (CI >60) and 39 were resistant to both rusts at the adult plant stage; 47 lines were resistant to leaf rust and 51 were resistant to stripe rust, with CI values of 0-20. Four landraces had moderate levels of APR (CI 21-40) to both rusts, 12 to leaf rust and 8 to stripe rust. Only two landraces (accessions 10975 and 11029) showed MR/MS reactions, and one (11438) had an MS/S reaction; the remaining produced S reactions to leaf rust at WRI. At CCRI Pirsabak, the majority of lines responded with MR/MRMS reactions, the remaining lines were susceptible. The 39 landraces identified to have resistance to both diseases may carry new APR gene(s) to one or both rusts, but must be further characterized prior to use as parents in national wheat breeding programs.