Comparison of sweetpotato clones grown in South Carolina using conventional and organic production methods

Authors: Wadl, Phillip; Williams, Livy; HORRY, MATTHEW - Clemson University; WARD, BRIAN - Clemson University

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2022
Publication Date: 3/22/2022
Citation: Wadl, P.A., Williams Iii, L.H., Horry, M.I., Ward, B. 2022. Comparison of sweetpotato clones grown in South Carolina using conventional and organic production methods. HortTechnology. 32(30:253-262. https://doi.org/10.21273/HORTTECH04979-21.
DOI: https://doi.org/10.21273/HORTTECH04979-21

Interpretive Summary: Sweetpotato is an important specialty crop grown in the United States (U.S.) and production has been increasing over the past 15 years and consumption is the highest it has been since the 1930s. Recently, there has also been special interest in organically produced sweetpotato because of the potential economic benefits. Despite the growing acreage associated with sweetpotato production there is still the problem of dealing with weed and insect pest management in both conventional and organic production. Organic production of sweetpotato using plastic mulches has been proposed and used successfully to mitigate weed and pest issues. Therefore, researchers from the USDA, ARS and Clemson University evaluated sweetpotato clones (cultivars and insect resistant breeding lines) for performance under conventional and organic production systems in Charleston, South Carolina. Overall, the results of this study show that black plastic mulch (BPM) is a viable production system for sweetpotato in South Carolina as well as other southern states in the U.S. Although the use of BPM did not consistently lead to significant increases in marketable yield in this study, the increases in overall undamaged storage roots due to insect pests suggest that increases in marketable yields may be possible. While further research needs to be carried out, it appears that plastic mulch may deter insects that damage sweetpotato roots while simultaneously decreasing weed pressure during the critical weed free period. These results provide important information for organic producers for determination of production system and variety.

Technical Abstract: Recently, there has been a resurgence of interest in sweetpotato production in South Carolina for processing and fresh market. There has also been special interest in organically produced sweetpotato. This study, conducted in 2016 and 2017 in the coastal plain of South Carolina (Charleston) was conducted to evaluate the performance of cultivars and advanced breeding lines under different soil types, microenvironments and bare ground versus plasticulture (black plastic mulch) growing conditions. In 2016, we evaluated 24 commercial and advanced breeding lines, and in 2017, 18 lines were evaluated. Data collected were: total yield (bushels/acre), marketable yield (bushels/acre), percentage United States (U.S.) grade number 1 roots, percentage yield difference, wireworm species and relative abundance, percentage uninjured roots, wireworm, Diabrotica, and Systena (WDS) severity index, percentage flea beetle damage, percentage grub damage, percentage sweetpotato weevil damage, percentage root rot, percentage root cracking, percentage roots misshaped, and wireworm species diversity. Results were mixed over years regarding genotype and organic black plastic mulch versus conventional bare ground cultural practice. Nevertheless, we identified several cultivars and advanced breeding lines that performed well under all conditions.