Evaluation of Orange Fleshed Sweet Potato ( Ipomoea batatas L.) Varieties for Yield and Yield Contributing Parameters in the Humid Tropics of Southwestern Ethiopia

摘要

Five orange fleshed sweet potato ( Ipomoea batatas L.) varieties: four collected from Adami Tulu Agricultural Research Center and one local variety with orange flesh were evaluated at field condition to identify the highest yielding and adaptable variety. The five varieties: Beletech (192026 II), Birtukanie (Saluboro), Kulfo (Lo-323), Tulla (CIP 420027) and a local variety were used as treatments and arranged in randomized complete block design with three replications. Data collected on yield and yield contributing parameters were analyzed using the GLM procedure of SAS version 9.2. Variety had significantly affected root diameter, marketable tuberous root yield and total tuberous root yield. Significantly the highest root diameter (4.9 cm), marketable tuberous root yield (0.78 t ha^?1) and total tuberous root yield (0.88 t ha^?1) were obtained from variety Tulla. The result of the correlation analysis also revealed that root diameter and number of tuberous roots per plant were significantly and positively correlated with marketable and total tuberous root yield. Likewise marketable tuberous root yield was also significantly and positively correlated with total tuberous root yield. This indicated sweet potato producers targeting tuberous roots should use root diameter, number of tuberous roots per plant and marketable tuberous root yield as selection criteria. Likewise, these yield and yield contributing parameters are important selection parameters which can serve as indicators of adaptability of the sweet potato to the study area and can also be utilized for making improvement in tuberous root yield of sweet potato. Besides, yield is an important agronomic index that shows the adaptability of a variety to its growing environment and accordingly variety Tulla outperformed the three improved OFSP varieties and the local variety in yield and yield contributing parameters. Therefore, variety Tulla (CIP 420027) was identified as the highest yielding and adaptable OFSP variety under the rain fed condition in the humid tropics of Southwestern Ethiopia at Jimma and potentially combats VAD at community level.