DETECTION OF VIRULENCES AND EVALUATION OF WHEAT LINES (Triticum spp.) FOR RESISTANT TO STRIPE , LEAF AND STEM RUST (Puccinia spp.) IN CENTRAL AND SOUTH-EAST ETHIOPIA

Abstract

Wheat rusts caused by Puccinia spp. are among the major biotic constraints of wheat production all over the world, including in Ethiopia. Nowadays different virulent races of stem, yellow and also leaf rust have evolved and threaten wheat production worldwide across all the wheat belt, among which Ethiopia is the most vulnerable. In view of the above facts, the present investigation was carried out to detect the prevailing virulent races, to identify resistance wheat lines and resistance genes to triple rusts in central and south eastern parts of the country. An inventory of 93 wheat lines and checks was made for triple rusts resistance under field conditions of Sinana and Debrezeit. Besides, 409 wheat lines including checks were tested for triple rust resistance at field conditions of Kulumsa Agricultural Research Center in 2015. The experiments were laid out in augmented design. Each plot consisted of two rows of 2-m long with 0.2 m between rows. Leaf, stem and yellow rust severity varied among wheat lines. Wheat lines also varied in their seedling infection types against races and isolates of triple rust in green house. The terminal severity and infection types varied across locations and wheat lines both at field and greenhouse conditions. The terminal severity for yellow rust ranged from 0 to 90S at Sinana and 0 to 40S at Kulumsa field conditions. The terminal severity for stem rust varied from 0 to 90S at Kulumsa and it was as high as 60S on the susceptible cultivar Kekeba at Debrezeit. The terminal severity of leaf rusts varied from 0 to 80S at Debrezeit. Of the 409 wheat lines tested 99.3%, 80.2% and 99. % were resistant to moderately resistant at field conditions of Kulumsa to yellow rust, stem rust and leaf rust, respectively. At Sinana 70.8% and 92.5% of wheat lines tested exhibited resistance to yellow rust and stem rust, respectively, with coefficient of infection ranging from 0 to 30. At Debrezeit 43% and 51% of wheat lines were resistant and moderately resistant to stem and leaf rust, respectively. Wheat lines Sr 50+Sr 45 # 35, Sr 45/Cs #20, Sr 45/Cs #21, Sr 45/Cs #25, Sr 45+Sr 2/Cs #28, Sr 45+Sr 2/Cs #29, Sr 45+Sr 2/Cs# 20, Sr 45+Sr 2/Cs# 33, Sr 45+Sr 2/Cs# 32, Thatcher+Lr 34, Westonia Sr 50+ Sr 26, Westonia Sr 24+ Sr 50 and Pavon Sr 24+ SR 26+Sr 31, were consistently resistant to triple rusts under field conditions across locations. However, the only wheat line resistant to triple rust both at field and seedling tests in green house was Pavon Sr 24+ SR 26+Sr 31, and hence it could be exploited in wheat improvement programs.