Effect of sesame gall midge (Asphondylia sesami Felt) on seed yield and yield components on selected sesame genotypes at Northern Tigray, Ethiopia

Sesame is an oil crop in Ethiopia primarily produced for the international market. Its production is challenged by both biotic and abiotic factors. Among the biotic factors, gall midge (Asphondylia sesami Felt) is one of the most important insect pests of sesame in western Tigray, Ethiopia. The objectives of the current study were to evaluate resistant sesame genotypes to sesame gall midge and assess higher yield under field conditions. A field experiment was conducted at Humera and Bereket during the 2019 cropping season using fifteen sesame genotypes. The genotypes were evaluated using a Randomized Complete Block Design (RCBD) and replicated three times. The results showed that there was significant (p<0.001) variation among the tested sesame genotypes in regard to yield (Kg/ha), flower abortion (%), and galled capsule (%), severity (%); while incidence (%) among treatments was not significant at all study areas. The highest yield was recorded from genotype Setit-1-sel-14, which produced 653.9 kg/ha at Humera and 562.5 kg/ha at Bereket. Conversely, the minimum yield was observed in genotype WARC103 with 250.6 kg/ha at Humera and WARC_076 with 190.4 kg/ha at Bereket. The lowest severity was observed in genotype Setit-1-sel-14, with percentages of 19.32% at Humera and 29.32% at Bereket. In contrast, the highest severity was recorded for genotype WaRC-103, with mean percentages of 44.56% at Humera and 55.56% at Bereket. This indicates significant variation in susceptibility to gall midge among the tested genotypes, which could be critical for breeding programs aimed at developing resistant varieties. Genotype Setit-1-sel-14 (17.53%, 1.79%) and (24.53%, 5.79%) had the lowest flower abortion and capsule damage at Humera and Bereket, respectively. Setit-1-sel-14 demonstrates superior resilience with the lowest recorded percentages of flower abortion (17.53%, 24.53%) and capsule damage (1.79%, 5.79%) at Humera and Bereket, respectively, while WARC103 shows the highest percentages (38.03%, 45.03%) for flower abortion and (6.6%, 13.6%) for capsule damage.