Reaction of introduced orange fleshed sweetpotato (Ipomoea batatas L.) genotypes for virus disease resistance and storage root yield performance under field conditions in Dilla and Hawassa, southern Ethiopia

Sweetpotato virus disease (SPVD) is among the biotic factors that cause significant storage root yield reductions in sweetpotato production. The experiments were executed at Dilla and Hawassa, southern Ethiopia, for two consecutive seasons (2017 and 2018), to evaluate the response of sweetpotato genotypes to SPVD, resistant reactions, and storage root yield performance. The materials were composed of eight genotypes. Design of the experiment was a randomized complete block design with four replications. Sweetpotato feathery mottle virus, sweetpotato chlorotic stunt virus, and cucumber mosaic virus were the major virus types detected from the evaluated genotypes using serological tests. NASPOT-12 and NASPOT-13 genotypes exhibited negative responses for all tested virus types. Results exhibited a broad range of differences in SPVD incidence (12.65–55.75%), severity (19.83–52.58%), and the relative area under the disease progress curve (AUDPC) (8.91–27.69%-days) with mean values for both locations and cropping seasons. The NASPOT-13 and NASPOT-12 genotypes showed consistent resistance reactions across location as well as cropping seasons. In addition, significant genotypic storage root yield variations (14.57–28.98 t/ha) were observed on average across the location as well as cropping seasons. In this regard, the genotype NASPOT-13 attained the highest storage root yield advantage (48.67 and 93.17%) over the standard and local check, respectively, across locations and cropping seasons. Overall, results pointed out that NASPOT-13 and NASPOT-12 showed consistent resistance reactions and lower SPVD intensities. Moreover, NASPOT-13 consistently provided a higher storage root yield across the locations in the two cropping seasons. As a result, NASPOT-13 with appropriate field management practices is suggested for sweetpotato production in the study areas and elsewhere with similar agro-ecological conditions. Furthermore, three varieties, namely, NASPOT-12, NASPOT-13, and Tomulabula, can be source of parent material for SPVD resistant genotype development in sweetpotato breeding programs. © 2023, Indian Phytopathological Society.