Ethiopia is one of the major producers of sesame in sub-Saharan Africa, and Ethiopian sesame particularly the whitish Humera type is among the highest quality in the world. However, the yield is lower than some of the producing countries due to many factors including low yielding varieties and bacterial blight disease severities. This study was conducted with the objective of evaluating sesame genotypes for yield and bacterial blight disease resistance during 2017/18 -2018/19 main cropping seasons at Dansha, Ethiopia. Sixteen sesame genotypes were evaluated with one local variety in randomized complete block design (RCBD) with three replications under hot spot area for bacterial blight disease infection. There was significant (P < 0.05) difference among the genotypes for yield, yield-related traits and bacterial blight disease severity. Higher seed yield was recorded in genotype WARC-063 (716.2 kg) with a mean yield advantage of 24.3% over the standard check Humera-1 whereas the lowest seed yield was ABOUT THE AUTHORS Weres Negash Golla (Mr) is a researcher in Tigray Agricultural Research Institute, Humera Agricultural Research Center. He has MSc in plant pathology from Mekelle University, Ethiopia. His research interest focuses on plant pathology, plant breeding, agronomy and agricultural economics.

An epidemic of disease is the progress of the disease in time and space. The objectives of the present study are to understand and compare the four nonlinear models for disease progress curves of five sesame varieties. The regression parameters estimation, standard error, R-square, Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) were estimated. The lowest values of standard error and the highest values of R-square were calculated from the monomolecular model. Also, the result showed that; the disease progress curve better fitted within the monomolecular model for each varieties with the smallest AIC and BIC values. This model is appropriate for modelling epidemics where there is a monocycle within a growing season. The Monomolecular model allows the estimation of the disease progression rate and an area under the disease progress curve was carried out to know the level of reaction to the disease. The lowest rate of fusarium wilt disease was recorded from Hirhir followed by Setit-2. However, the highest value was recorded from Setit-3 followed by Setit-1. A highest value of area under disease progress curve (AUDPC) was calculated from Setit-3. However, the lowest was calculated from Hirhir. Varieties with low disease incidence could be useful in breeding programs aimed at developing varieties with higher resistance to Fusarium wilt disease.

Gall midge (Asphondilia sesame Felt) is one of the most serious insect pests of sesame threatening sesame production in Tigray, Ethiopia. The aim of the present study was to assess distribution and incidence of sesame gall midge and its association with different agronomic practices. Field survey was conducted in Kafta-Humera, districts in 2019 cropping season. A total of 60 farmers’ fields were assessed for the prevalence and incidence of the insect. Results indicated that 94% of farmers’ fields were infected by sesame gall midge from the total assessed fields. Sesame gall midge incidence ranged from 33.33-100% in the assessed Kebelles. The mean incidence gall midge was 81.74%. The highest mean incidences were recorded from Bereket, Adebay, Lugdi, Rawuyan. However, the lowest was recorded from Freselam.  Mean incidence of sesame gall midge was significantly (p < 0.05) variation with the sowing date, altitude and crop rotation. The lowest mean incidences of sesame gall midge, flower abortion and galled capsule were recorded from the early sowing date, lower altitude and previous grown with sorghum. Overall results of the present study indicated that sesame gall midge is one of the major challenges to sesame production in study areas. Therefore, efforts should be put in place to manage the insect via integration of appropriate management.

The production of sesame (Sesame indicum L.), an important oil crop produced for export in Ethiopia, is affected by environmental and biotic factors as well as management practices. Determining the optimum plant population in optimum moisture areas for sesame is crucial to boost sesame productivity. A field experiment was conducted at Zuria-Dansha, in optimum moisture areas of western Tigray to evaluate yield performance of sesame varieties at different levels of plant population. The experiment was laid out in RCBD in factorial arrangement with three varieties of sesame (Gida-Ayana, Humera-1 and Hirhr) and four plant population (80,000, 124,444, 250,000 and 666,666 plants/ha) in three replications. The result revealed that varieties and plant population significantly differed in yield and yield related traits. The variety Gida-Ayana recorded maximum fertile capsules per plant, thousand seed weight, seed per capsule and oil content (%) while the local variety Hirhr recorded the least. The yield components like: fertile capsules per plant, seed per capsule and thousand seed weight were highest in the low plant population than highest plant population but oil content (%) was not affected by different levels of plant population. The highest seed yield was obtained from variety Gida-Ayana grown at 250,000 plants (10 cm × 40 cm) which significantly increases yield by 34.75% as compared with local variety Hirhr with the same plant population. Hence, it can be concluded that higher seed yield and oil content (%) of sesame could be obtained by using Gida-Ayana variety sowing at the plant population of 250,000 plants/ha (40 cm × 10 cm) under optimum moisture areas of western Tigray and similar agro-climatic conditions.