Maize has become one of the most important food crops in the Rift Valley region of central Ethiopia. Due largely to drought stress, maize yields are usually less than 1 t/ha. This region has a bimodal rainfall pattern which is characterized by a short season with erratic rainfall beginning in early April, followed by the main rainy season starting in late June or early July. Farmers traditionally plant long duration local varieties during the short rains which must survive the drought stress in June and then mature during the main season. Early maturing varieties have been developed or introduced which can be planted at the beginning of main rains, thereby avoiding the prolonged period of stress between the two rainfall periods. CERES maize, a crop simulation model, was used to simulate the relative productivity of using a late maturing variety planted early and an early maturing variety planted late. Simulations were run using 8 years of weather data from Adamitulu and 10 years from Melkasa, both within the Rift Valley. Of the treatments simulated, planting an early-maturing variety like Katumani at the beginning of the long rains is the most stable for yield across years and sites. The long duration cultivar A210 planted early was not stable for yield but frequently out-yielded the other treatments by a significant margin. Germplasm development for the rift Valley should continue to focus on improving early-maturing types which can be planted at the beginning of the long rains, but should also look at developing later maturing, drought tolerant genotypes and improving management practices for early plantings in the short rainy season.

English

9801|AGRIS 9702|anterior|R97-98PROCE|FINAL9798

Jose Juan Caballero

CIMMYT Publications Collection