The level of virus contamination on sweetpotato germplasm resources in Ethiopia was determined. Sweetpotato (Ipomea batatus) accessions in fields at Awassa and Wondo Genet Research Stations had 85% typical virus symptoms with up to 100% incidence. The associated viruses were identified by Enzyme-linked immunosorbent assay (ELISA). Accordingly, out of 57 accessions serologically tested from Awassa, 22 and 21 were found to be infected by Sweetpotato feathery mottle virus (SPFMV) and Sweetpotato chlorotic stunt virus (SPCSV). Only one was infected by Sweetpotato virus 2 (SPV2). Similar serological analysis of 122 accessions from Wondo Genet revealed that SPFMV is the most frequent (64.7) followed by SPCSV (10.7%) and SPV2 in only two accessions. This is the first report of the occurrence of SPCSV and SPV2 in Ethiopia. There was a high virus contamination level of sweetpotato germplasm resources in Ethiopia.

The objectives of this study were to identify high yielding and stable medium maturity soybean varieties across environment and examine the influence of genotype × environment interaction (GEI) on grain yield of soybean varieties in western Oromia. Seven early soybean varieties were evaluated at five locations (Bako, Gute, Billo, Chewaka and Uke) using randomized complete block design (RCBD) with three replications for two consecutive years (2016 and 2017). Combined analysis of variance showed that grain yield was significantly (P<0.01) affected by environments, genotypes and GEI. The environment, genotype and genotype by environment interaction accounted for 57.4, 20.9 and 19.8% variations, respectively. The first two principal components (IPCA 1 and IPCA 2) were used to create a two-dimensional genotype and genotype by environment interaction (GGE) biplot and explained 68.9 and 15.6% of the total sums of squares of GEI, respectively. According to the average environment coordination (AEC) views of the GGE-biplot, soybean variety Didhessa and Hawassa-04 were identified as the most stable and high yielding varieties. In addition, Didhessa and Hawassa-04 also showed better stability performance according to AMMI stability value (ASV), genotypic selection index (GSI), Wricke's ecovalence and cultivar superiority measure among the evaluated varieties whereas variety Davis and AFGAT were identified as the least stable and low yielding variety. Therefore, among medium maturing soybean varieties, Didhessa, Hawassa-04 and Cheri were recommended for further production in most soybean growing areas of western Oromia.

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Introduction Potato (Solanum tuberosum L.) is the most important vegetable crop, constituting the fourth most important food crop in the world [1,2]. It is one of economically most important tuber crops in Ethiopia that play key roles as a source of food and cash income for smallholder farmers [3].