Valuable sources of resistance in the Ethiopian durum wheat landraces to UG33 and other stem rust races

The evolution of new stem rust races with broad virulences on many of the resistance genes deployed in wheat breeding gave additional impetus to search for new sources of resistance. This study was conducted to identify sources of resistance in the Ethiopian durum landraces to Ug99 (TTKSK) and other prevalent races at Debre Zeit Agricultural Research Center, Ethiopia. The experiment was conducted in the 2009 main and 2010 off-seasons. In 2009 main season, a total of 991 durum wheat lines previously collected from different parts of the country were tested whereas in 2010 off-season, only 132 entries were being evaluated. The entries were sown in two rows of one meter long plots together with susceptible checks. Spreader rows of susceptible varieties were sown and being inoculated three times starting from stem elongation with mixtures of stem rust races including Ug99 (TTKSK) using injection method. Rust scores were taken three times using a modified Cobb’s scale. Leaf rust appeared early in the season and most of the landraces exhibited susceptible reaction to this disease. Out of the total entries, 132 exhibited combined resistances to stem and leaf rust diseases and those were selected for further test in the 2010 off-season. In the subsequent test, 28 lines were identified to have high level of stem rust resistance comparable or better than the resistant checks. The selected durum landraces could be exploited in wheat breeding program.