Drought resistance in durum wheat

Durum wheat is widely grown as a rainfed crop in the semi-arid tropics. Its production is low and variable from season to season due to frequent drought-stress. Characterization of target environment and employing both analytical and empirical breeding approaches would speed up progress in the development of cultivars with improved adaptation to the prevailing weather conditions.Analysis of historical weather data and a crop growth model were used to predict the growing season and the optimum plant growth cycle in six different ecological regions of Ethiopia. The matching of crop development to the prevailing soil water availability patterns is considered as a major step towards sustainable durum wheat production.High yield and yield stability are equally important breeding objectives under drought conditions. The cause-effect relationships of the duration of vegetative period, the duration of grain-filling period, yield components (number of spikes/m 2, kernels/spike, kernel weight) and grain yield revealed a complex pattern of relationships. Longer grain-filling period, increased number of kernels per spike and limited tillering were found to be associated with drought- resistance.Increasing water use efficiency is the major focus of the dryland cropping system. The different definitions of water use efficiency are explained. Water use efficiency on the basis of grain yield proved the most valuable parameter. The ratios of water used before anthesis and after anthesis by drought-resistant and -susceptible cultivars were different.Relative growth rate (RGR) and its components (leaf area ratio, LAR, and net assimilation rate, NAR) changed with growth stage and moisture availability. Drought-resistant cultivars were characterized by a fast growth rate in the beginning and slow growth later. Deep rooting and a low shoot:root ratio are effective components of drought-resistance.Durum wheat straw is one of the major feed sources. The quality of straw varied among cultivars, but did not correlate with drought-resistance. Drought-stress considerably improved straw quality, due to reduced remobilization of assimilates.The research showed that there is considerable potential to improve the current low and variable durum wheat production in the semi-arid regions

The use of remote sensing to quantify wetland loss in the Choke Mountain range, Upper Blue Nile basin, Ethiopia

Wetlands provide multiple ecosystem services such as storing and regulating water flows and water quality, providing unique habitats to flora and fauna, and regulating micro-climatic conditions. Conversion of wetlands for agricultural use is a widespread practice in Ethiopia, particularly in the southwestern part where wetlands cover large areas. Although there are many studies on land cover and land use changes in this region, comprehensive studies on wetlands are still missing. Hence, extent and rate of wetland loss at regional scales is unknown. The objective of this paper is to quantify wetland dynamics and estimate wetland loss in the Choke Mountain range (area covering 17 443 km<sup>2</sup>) in the Upper Blue Nile basin, a key headwater region of the river Nile. Therefore, satellite remote sensing imagery of the period 1986–2005 were considered. To create images of surface reflectance that are radiometrically consistent, a combination of cross-calibration and atmospheric correction (Vogelman-DOS3) methods was used. A hybrid supervised/unsupervised classification approach was used to classify the images. Overall accuracies of 94.1% and 93.5% and Kappa Coefficients of 0.908 and 0.913 for the 1986 and 2005 imageries, respectively were obtained. The results showed that 607 km<sup>2</sup> of seasonal wetland with low moisture and 22.4 km<sup>2</sup> of open water are lost in the study area during the period 1986 to 2005. The current situation in the wetlands of Choke Mountain is characterized by further degradation which calls for wetland conservation and rehabilitation efforts through incorporating wetlands into watershed management plans

Information, motivation and resources: the missing elements in agricultural pesticide policy implementation in Ethiopia

To promote pesticide governance that protects the environment and human health, Ethiopia has developed a legal framework for pesticide registration and control. However, in Ethiopia, pesticides are still registered, traded and used inappropriately. This research analyses how Ethiopia's pesticide policy is implemented and identifies the barriers for an effective implementation of this policy. With a theoretical framework based on the information, motivations and resources of relevant actors, data are collected from state pesticide experts, traders and end users (farmers) through in-depth interviews. The overall result reveals that major gaps exist between pesticides policy on paper and its implementation in practice. The key policy actors scored low on each of the three characteristics: they have poor information available, have low motivation to implement policies and lack sufficient resources. Involvement of and collaboration with private actors is likely to improve the implementation of pesticide governance, and contribute to sustainability in agricultural and food systems in Ethiopia

Haricot bean agroecology in Ethiopia: Definition using agroclimatic and crop growth simulation models

Bean (Phaseolus vulgaris L.) is an important food and cash crop grown in diverse environmental settings in Ethiopia. Its production is very heterogenous in terms of ecology, cropping system and yield. This study analyses the agroclimatic resources of 18 representative bean growing sites in Ethiopia and assesses the potential yield and moisture deficit stress using DRYBEAN (DSSAT V.3) growth model. Annual rainfall of various locations ranged from 580 mm (Mekele) to 1995 mm (Gore). Seasonal rainfall varied from 270 mm (Babile) to 1650 mm (Gore). The length of the growing period is from only 80 days (Mekele) to more than 220 days (Jimma). Among the agroclimatic variables, annual rainfall, seasonal rainfall, length of the growing period and altitude (temperature) are important factors to cluster the bean growing regions into 3 major and 6 minor homogeneous groups in agronomic sense for strategic planning. Simulated yield potential varied from 1.6 t ha^-1 (Jijiga) to 3.3 t ha^-1 (Bako). Planting date has a significant impact on simulated yield in the sub-humid and semi-arid clusters. Yield losses for each day of delayed planting after the effective onset of rainfall reached up to 60 kg ha^-1 day^-1. Moisture deficit stress was found to be an important limiting factor in the semi-arid and moderately limiting in the sub-humid regions. The analysis established that bean improvement work should focus on the development of high-yielding, long-maturing genotypes for multiple cropping systems in the humid regions. In the semi-arid regions emphasis should be on the development of drought tolerant and early maturing cultivars which fit well with efficient soil and water conservation practices