Progrès dans la science et la technologie des cultures

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Evaluating the Adaptability of Released and Introduced Orange Fleshed Sweet Potato Varieties in Selected Highland Areas of Southern Ethiopia

Bililign Mekonnen, Fekadu Gurmu

Sweet potato is a versatile crop playing an immense potential in the global food system. The objective of this study was to select outperformed sweet potato varieties to recommend for highland areas in Ethiopia. Nine Orange Fleshed Sweet Potato varieties (OFSP) were evaluated at two highland areas, Bursa (2348 m.a.s.l) and Gedeb (2358) districts, Sidama region and Gedeo zone of Southern Ethiopia, respectively during the main cropping season over two years. A Randomized Complete Block Design (RCBD) in three replications. Data were recorded on sweet potato virus disease score, above ground fresh biomass, root length, root diameter, marketable root yield, unmarketable root yield and total root yield and subjected to combined analysis. The results of analysis of variance showed highly significant differences (p<0.001) between varieties, locations and their interactions. The three way interaction effects (variety × location × year) were significant at p<0.005) for marketable and total root yields and non significant for the rest of traits studied.

This suggests that there is an opportunity to select better adapted varieties for highland areas. Combined mean value for SPVD scores ranged from 1.58 to 2.67 (1 to 9), these values indicated resistance/tolerance ranges, implying that most of the tested varieties showed tolerance to SPVD in the tested areas. Variety Mayayi followed by Alamura gave the highest above ground biomass of 20.50 t ha^-1 and 20.22 t ha^-1, respectively, while Kyoyabwerer gave the lowest yield of 8.00 t ha^-1 as compared to the others. The maximum marketable root yield was recorded from Kulfo (13.15 t ha^-1) followed by Kabode (10.05 t ha^-1) and Alamura (9.50 t ha^-1) whereas the minimum value of 5.70 t ha^-1 was obtained from NASPOT-8. Three varieties, namely Kulfo, Kabode and Alamura gave a total root yield of 13.53 t ha^-1, 10.71 t ha^-1 and 10.40 t ha^-1 respectively. Although Kulfo variety better root yield, however, it is characterized with low Dry Matter Content (DMC) so that its acceptance by farmers remained very low. Varieties Alamura and Kabode were improved varieties and they are known for their high DMC. There is an increasing demand for these varieties because of their high DMC and beta carotene content. Introducing these varieties into cereal based farming systems can reasonably contribute in highland areas where malnutrition is a serious problem due to high dependency on cereal crops. Therefore, varieties Kabode and Alamura should be recommended for production in highland areas that goes up to 2350 m above sea levels.