VARIATION IN ETHIOPIAN BARLEY LANDRACE POPULATIONS FOR RESISTANCE TO BARLEY LEAF SCALD AND NETBLOTCH

One-hundred and eighty landrace populations and six-hundred single-hea d plants selected from 60 promising populations were evaluated for res istance to scald and netblotch at three locations in Ethiopia. Each ac cession was tested with and without the application of 50% of the reco mmended rate of fertilizer at planting. Plants were rated for disease attack two to four times during the season. Both diseases were enhance d by the application of fertilizer and were more severe at the testing sites of Holetta and Bekoji than at Sheno. The difference in disease resistance among and within populations was considerable. Moreover, po pulations from Arsi and Bale tend to be more susceptible to scald but more resistant to netblotch than populations from other regions. Popul ations collected from higher altitudes were more resistant to scald, b ut susceptible to netblotch, than were populations from lower altitude s. The paper illustrates approaches to the identification of valuable genotypes from landrace populations that can be incorporated into a br eeding programme for the development of improved varieties with resist ance to the principal diseases of barley in Ethiopia.