Factors Affecting Greenhouse Sweetpotato Slip Production

ABSTRACTSweetpotato certified seed producers rely on fast propagation of virus-indexed slip plants in the greenhouse to obtain transplants for the production of first generation of storage roots. Effective fertilization is important for greenhouse vegetative propagation, but relevant guidelines are rare. Greenhouse experiments were conducted in 2011 and 2012 using sweetpotato (Ipomoea batatas (L.) Lam.) var. Covington, Beauregard, and Evangeline to evaluate effects of fertilizer rate on slip production. The most commonly used commercial fertilizer mix (20N–10P–20K) was applied at the rates 50, 100, 200, 300, 400 mg·L−1 of N. Plants were harvested nine times over the season in both years. Total nodes on vines and total slip fresh weight were determined. ‘Evangeline’ produced more nodes—that is, more plants—than ‘Beauregard’ and ‘Covington’, and ‘Beauregard’ produced the highest slip fresh weight, followed by ‘Evangeline’ and ‘Covington’. Effect of fertilizer rate on vine node count was similar for early (h...