Growth Regulators Combined with Grafting Increase Flower Number and Seed Production in Sweet Potato

Abstract

Four sweet potato [Ipomoea batatas (L.) Lam.] cultivars responded differently to growth regulator application for number of flowers produced, percentage capsule set, and number of seeds produced. Gibberellic acid, 2,4-D, and BA application resulted in the highest number of flowers by `Jewel', `Shore Gold', and `Vardaman) plants, respectively. Application of GA3 to `Jewel', 2,4-D or ethephon to `Shore Gold', and BA to `Vardaman' produced the highest number of seeds. Grafting to rootstock of Z. carnea Jacq. spp. fistulosa (Mart. ex Choisy) D. Austin increased flower numbers, percentage capsule set, and number of seeds in all cultivars. The effects of growth regulators and grafting were additive for flower numbers, percentage capsule set, and number of seeds. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA), (2,4-dichlorophenoxy) acetic acid (2,4-D), (2-chloroethyl) phosphoric acid (ethephon), and (1α, 2β, 4a α, 4b β, 10)-2,4a,7-trihydroxy-1-methy1-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-Iactone (gibberellic acid; GA3).