Effects of prohexadione-calcium on sweet potato vegetative growth as influenced by cultivar and nitrogen

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.