KULUMSA RESEARCH CENTER, ETHIOPIAN AGRICULTURAL RESEARCH ORGANIZATION
P.O. Box 489, Arsi, Asella, Ethiopia.
Evaluation of introduced bread wheat germ plasm under Ethiopian conditions.
Bedada Girma, Zewde Alemayehu, Balcha Yaie, Thomas Payne, and Amsal Tarekegn.
Bread wheat breeding objectives in Ethiopia include high yield, disease resistance, tolerance to stress environments, resistance to lodging and shattering, and grain quality. The major sources of germ plasm introductions are CIMMYT/Mexico and CIMMYT/ICARDA/Syria. In 1997, six nurseries consisting of nearly 700 entries were introduced and evaluated under quarantine at Holetta Research Center, a hot-spot for S. tritici. Resistance/tolerance to Septoria leaf blotch, yield potential, and agronomic appeal were the major factors in screening the materials for high rainfall areas. However, leaf blotch is not a major factor in evaluating genotypes in semi-arid nurseries. After field evaluation and scoring, seed selection was used to scrutinize and advance promising materials. Based on different criteria used in screening, about 31 % of the introductions were promoted to the next testing stages under different environments.
Ethiopian bread wheat cultivars and their morphological descriptions.
Zewdie Alemayehu, Balcha Yaie, Bedada Girma, Desalegn Debelo, and Bekele Geleta.
Distinguishing characteristics of wheat can be used in monitoring the purity of varieties under production. Nine released bread wheat cultivars and one promising line were grown and evaluated for characteristic differences under three environments for three seasons. Dhera, Kulumsa, and Bekoji represented low, medium, and high moisture environments, respectively. Plant, ear, and grain characters were the major factors used in describing the varieties. The distinguishing characters were recorded when appropriate plant stages showed full expression of the characters. Several descriptors were used to describe the 10 genotypes. The cultivars were distinctively variable for some characters and similar for others. The result of this work will serve as a guideline to wheat seed growers, seed certification agencies, and researchers.
Feedback from farmers on the status of released bread wheat varieties in Chilalo Awraja, Arsi Zone, Ethiopia.
Zewdie Alemayehu, Regassa Ensermu, Balcha Yaie, Bedada Girma, Girma Taye, and Mohammed Hassena.
A survey of wheat farmers conducted in 1995 in four woredas (districts) of Chilalo (Awraja, Ethiopia (Etheya, Tiyo), Lemu-bilbilo, and Asasa) determined the status of released wheat varieties, assessed the impression of small-holder farmers on the merits and demerits of the varieties, and evaluated the grain yield and quality parameters deemed important by farmers for the released varieties. Twelve wheat varieties were identified. The major varieties were Pavon-76, Dashen, and Batu in Etheya/Tiyo; Enkoy, Dashen, and K6295-4A in Lemu-bilbilo; and Pavon-76, Dashen, and K6295-4A In Asasa. Grain yields ranged from 2,610 kg/ha for Enkoy to 7,259 kg/ha for HAR 1709, with a grand mean of 3,473 kg/ha. In general, farmers preferred Pavon-76, Dashen, Enkoy, K6295-4A, and Batu. Farmers in Arsi were eager to test and adopt new varieties of wheat. Therefore, periodical monitoring and evaluation of varieties is essential to determine the status of varieties in the farming community and provide important feedback to researchers.
Agronomic performance and stability of breat wheat geneotypes in the national yield trial of Ethiopia.
Zewdie Alemayehu, Balcha Yaie, Bedada Girma, Osman Abdalla, Desalegn Debelo, and Bekele Geleta.
Twenty bread wheat genotypes were tested in Ethiopia over 35 environments to evaluate their grain yield performance and stability across locations. An additive main effect and multiplicative interaction model was used to measure the performance of genotypes and 'genotype x location' interaction. In addition, disease resistance of the genotypes was taken into consideration. Mean grain yield of the varieties ranged from 3,383 to 4,144 kg/ha, with a grand mean of 3,933 kg/ha. The first principal component explained 46 % of the interaction. The principal componet values ranged from 45.96 to -31.65, showing wider adaptability of the six genotpes. Four genotypes showed a positive interaction with high moisture environments. Based on their performance across locations, HAR 1775 and HAR 1875 were selected as candidate varieties for verification and possible release in 1999.
DEBRE ZEIT AGRICULTURAL RESEARCH CENTER - EARO
P.O. Box 32, Debre Zeit, Ethiopia.
Effect of heading date on stem rust development in durum wheat.
Yeshi Andenow and Mengistu Hulluka.
Three stem rust-susceptible lines of durum wheat that required 55, 68, and 82 days from planting to heading were classified as early, intermediate, and late maturing types, respectively. These lines were planted at Debre Zeit, Ethiopia, on alfisol/mollisol soils in paired 9-m^2^ plots following a randomized complete block design in four replications. A plot from each line was protected from stem rust by application of the fungicide Propiconazole. In the four test seasons, clear differences in the effect of the fungicide were observed, with mean grain yield losses of 35, 38, and 36 % for the early, intermediate, and late maturing types, respectively. Maturity alone was insufficient to determine affect of yield loss from the disease. The effect of the rust was highest on the intermediate maturing type, because the plants were green during the peak seasons of the rust epidemic. Rust severity levels and grain yields were inconsistent in the late maturing type.
Evaluation of durum wheat using broadbed and flat drainage systems.
Demissie Mitiku, Efrem Bechere, and Bemnet Gashawbeza.
Durum wheat is traditionally grown on highland vertisols in Ethiopia. These soils are productive, if excessive water accumulation can be managed. In a regional durum wheat variety trial, 20 genotypes were compared in a randomized complete block design trial with four replications at three locations. Our study identified superior genotypes when grown on vertisol fields using broad bed, furrow, or water-managed plots on flat, level terrain. The trials were conducted in 1997 at Bichena, Enewary, and Chefe Donsa. In general, grain yield was higher with broad bed and furrow planting structures. Differences in genotype performance suggest genotype by environment interaction between the two planting systems, and germ plasm adaptation to a particular planting methodology.
ADET AGRICULTURAL RESEARCH CENTER
P.O. Box 8, Bahir Dar, Ethiopia.
Yield potential of durum wheat on well-drained Nitosol soils.
Tadesse Dessalegn and Landuber Wondale.
Traditionally in northwestern Ethiopia, durum wheat land races have been grown mainly on waterlogged soils (e.g., Vertisols). Because of poor drainage and associated yield-limiting factors, the yield potential under these conditions is discouraging (< 1 t/ha). Some farmers are abandoning the crop, and its in situ genetic diversity is under threat. Possibilities to stop this trend and increase productivity include improved soil-drainage systems. Alternately, selection of durum wheat genotypes tolerant to waterlogged condition is possible. To identify such varieties, a yield trial was conducted at the Adet Agricultural Research Center in 1996 and 1997. Semidwarf and medium-tall durum wheat varieties were tested, and all grew vigorously. Significant differences were observed in most traits. Some entries outyielded all checks, with grain yields of 3.5 t/ha achieved.
Genotype by environment interaction for grain yield of bread wheat in northwestern Ethiopia.
Tadesse Dessalegn, J. Crossa, Landuber Wondale, and T.S. Payne.
A bread wheat yield trial investigated the 'genotype x environment' interaction of 14 genotypes grown at four locations for 3 years in northwestern Ethiopia. Additive main effects and multiplicative interaction analysis were used to analyze "G x E', and the interaction was found to be significant (p = 0.01). Mean grain yield of genotypes across environments ranged from 3,644 to 4,897 kg/ha. Several genotypes were specifically adapted; few genotypes showed stable performance across environments but with low grain yield performance. Further testing is necessary to develop genotypes that combine high and stable grain yield performance across environments or to define agroecologies with more precise site specificity.