Genetic gain in fruit yield potential and associated traits of tomato [lycopersicon esculuntum (L.) Mill] varieties in Ethiopia

In the current study conducted in the Sodo district, 16 tomato varieties released between 1997 and 2015 were evaluated. The experiment followed a randomized complete block design with three replications during the 2024 cropping season. The analysis of variance revealed highly significant differences among the varieties for all traits, except for the number of primary branches per plant and the number of seeds per fruit. The average annual rate of increase per year of variety release, calculated from the slope of the linear regression graph of mean fruit yield against the year of variety release, was estimated to be 0.127 tons per hectare. This corresponds to a relative genetic gain of 0.40% per year. In the last 18 years, recently released varieties demonstrated a yield improvement of 0.40 kg per hectare (1.47%) compared to the oldest varieties. Significant positive trends were observed for marketable yield, fruit diameter, fruit length, fruit width, fruit growth rate per plant, and fruit yield per day. On the other hand, all other traits showed a significant decreasing trend over the years of variety release. Fruit growth rate per plant exhibited high genetic advance (509.61%), while total soluble solids showed the lowest genetic advance (0.74%). The study concluded that the improvement in fruit yield over the past 18 years has been inconsistent. Therefore, further efforts should be strengthened and continued to achieve more progress in these and other relevant traits. This will contribute to the development of an appropriate strategy for tomato fruit yield improvement in the country.