Performance of improved sweetpotato (Ipomoea batatas L.) cultivars under different soil types of Samoa

Abstract

There is need to diversify crop production in Samoa which currently depends mainly on taro crop, that has proved to be susceptible to fungus and other diseases, to as safeguard against risks of crop failures and adapt to climatic changes. The potential of introducing sweetpotato as a second staple food in Samoa is explored in this study. The study analyses the suitability of sweetpotato cultivars in Samoan agro-environment and major soil types. For this purpose a twenty week pot experiment was conducted to investigate the performance of three improved sweetpotato cultivars (IB/PR/12, IB/PR/13 and IB/PH/03) on four different types of soils in Samoa (Savaia calcareous sandy loam, Matafa’a red acidic, Faleula silty clay and Saleimoa silty clay) in a factorial arrangement of treatments in randomised complete block design with three replications. Results revealed that soil type had a significant effect on vine growth, and storage root yield with the best yield obtained in the silty clay soils having high K content. Retarded plant growth observed under the acidic soil having low K content resulted in lowest storage root yield. A significant varietal difference was recorded in sweetpotato growth and yield. IB/PH/03 was inferior in vine length, but produced comparatively highest number of vines per plant, and storage root yield attesting its adaptability in all the four tested soil types of Samoa and has potentiality to be promoted for wider adoption. A follow-up field study is needed to verify our preliminary results under pot culture on different soil types of Samoa.