Occurence, distribution and management Strategies for Ascochyta blight (Ascochyta Rabiei pass.) Of chickpea (Cicer arietinum l.) In Ethiopia

Chickpea (Cicer arietinum L.) is one of the important pulse crops in Ethiopia. However, its production is affected by pest and disease. Among the diseases Ascochyta blight caused by Ascochyta rabiei, is considered to be the most devastating. A survey was conducted during August 2015 to February 2016 to determine the status of blight disease affecting chickpea in the major growing areas of Ethiopia. More than 250 fields were visited at research centers and on farmers’ field during the growing season. The result indicated that ascochyta blight was not distributed in all surveyed areas. The prevalence of the disease was low ranging from 0 to 45.6%. AB was observed in 30 of the 251 fields and incidence ranged from 0 to 25 % with mean of < 10%. The highest mean incidence was in Ensaro district of Amhara region (46.6%) followed by Lume district of Oromia region (15%). The severity varied from 1 to 7 with mean severity of 1 to 3.2 which was observed in few fields indicating that low severity of the disease on chickpea in the country. The low incidence and severity could be attributed to environmental factors. Erratic rainfalls and rise in temperature are increasingly becoming a challenge under the changing scenario of climate in Ethiopia. As a consequence of it, chickpea blight disease severity levels have declined throughout the chickpea growing regions in Ethiopia. Thirty nine advanced chickpea breeding lines were evaluated for blight resistance under field conditions during the main season of 2013/14-2014/15. The experiment was laid out in a randomized complete block design with 3 replications. Disease incidence and severity was assessed at seedling, flowering and full podding stages. There was a considerable variation between genotypes with respect to their disease reaction at three stages (P< 0.001). This study revealed that none of the 39 genotypes was asymptomatic, whereas 36 genotypes were resistant and two were moderately resistant on average basis. Variability in blight severity due to genetic differences among the genotypes, environment, and that due to genotype × environment interaction was highly significant (P < 0.001). Genotype × environment (G × E) interaction contributed only 3.33% of total variation, revealing stability of the phenotypic expression across environments. Correlation analysis of disease severities exhibited high significant association between average severity and seedling (r = 0.65**), flowering (r = 0.96**) and full podding (r=0.95**) stage at P< 0.05. Ultimately, genotypes which showed resistance may be exploited for the development of resistant cultivars against blight disease. Progress in chickpea breeding has been constrained by lack of good early maturity with resistance to blight disease in the short-season semi-arid environment of Ethiopia. Field experiment was conducted during 2014/2015 growing season to evaluate yield and yield components of early maturing chickpea grown under rainfed conditions. The experiment was carried out in a randomized complete block design in three replications at Debre Zeit research station. Fifteen chickpea lines obtained from ICRISAT were evaluated. Chickpea genotypes were significantly different for evaluated traits at P < 0.05. Days to 50% flowering ranged from 43 to 53 and plant maturity from 103 to 111 days. The earliest flowering line was DZ -2012-CK- 00075 (43 days) whereas earliest maturing genotype was DZ-2012-CK-00019 (103 days). Line DZ-2012-CK-00019 produced highest grain yield(1960kg/ha) followed by DZ-2012-CK- 00015(1950kg/ha). Both correlation and path analysis showed that seed weight, biomass yield and number of pod per plant could be used as a selection index for chickpea improvement.