Abstract

The sweet potato (Ipomoea batatas Lam.) under high nitrogen produces excess vines at the expense of storage root. Prohexadione-Ca has been used to reduce vegetative growth and increase harvest efficiency and yield in many fruit and row crops. Using Prohexadione-Ca to reduce vegetative growth in sweet potato may enhance storage root yield and harvest efficiency. This study examined the effects of Prohexadione-Ca on sweet potato vegetative growth. In 2010 and 2011, two week-old plants of the sweet potato cv. O’ Henry and SC1149-19 were sprayed with 0 and 810 mg a.i. L^-1 Prohexadione-Ca over N levels of 0, 2.7 and 5.3 g plant^-1in the greenhouse. Vine length was significantly (P≤0.05) reduced by Pro-Ca. The reduction in vine length was not affected by cultivar or N. Internode length was significantly (P≤0.05) reduced by Pro-Ca. Prohexadione-Ca treated plants had significantly higher leaf thickness and vine diameter compared to untreated plants. However, leaf area and vines plant^-1 were unaffected by Prohexadione-Ca. Data from this study indicated that Pro-Ca has the potential of being used to manipulate source-sink relationship for higher storage root yield in sweet potato.

Key words: Prohexadione-calcium, sweet potato, vegetative growth, growth inhibitors, gibberellins, cultivar, nitrogen.