Relationship between vine propagation method, and growth and yield in sweetpotato[Ipomoea batatas(l.)lam]

Abstract

Timely availability of high volumes of good quality planting materials is a challenge especially for crops propagated by vegetative means such as sweetpotato [Ipomoea batatas (L.) Lam.]. Zambian growers rely on volunteer plant sprouts to generate vines. Recently the use of root sprouts has been promoted. Past studies have shown the wide influence of method of propagation of sweetpotato planting materials on growth and yield. The objective of this study was to investigate the effect of propagation method on the development and yield of sweetpotato. This study evaluated the physiological performance of the crop propagated by vines from either volunteer plants or storage roots. Varietal effects, as well as propagation method by variety interaction effects were investigated. Four varieties were used; Orange Chingovwa, Chingovwa, Olympia and Zambezi. This was a factorial experiment arranged in a Randomized Complete Block Design (RCBD) with four replications. The experiment was conducted at Kaithinde agricultural camp of Lundazi district of eastern Zambia. Specific Leaf Area (SLA), Leaf Area (LA), Leaf Area Ratio (LAR), Leaf Area Index (LAI), Vine Length (VL), Storage root diameter (RD) and length (RL) and the root/ shoot ratios (RSRs) were determined. Root yield at full maturity was also measured. There were no differences in establishment rates between methods probably because plants were grown under optimal conditions. There were significant differences in LA, LAI and the VL between propagation methods in the early growth phase (p ≤ 0.05). During this phase the LA was higher in plants grown from volunteer sprouts (0.27 m2) in comparison to the root sprouts’ treatments (0.21 m2). The differences in LA in the early phase may have been due to varying pre-planting shocks experienced by the vines from the two methods. Volunteer sprouts’ treatment also had higher VL (222.90 cm) compared to the root sprouts treatment (154.00 cm) during this phase probably due to differing pre-planting shocks experienced by the vines from the two methods. Both LA and VL were not different between propagation methods in the latter two phases of growth evaluated (p ≤ 0.05). Total storage root yield per plant (0.67 kg for root sprouts’ and 0.71 kg for volunteer sprouts’ respectively) was not influenced by propagation method (P ≤ 0.05). This study concluded that propagation method does not affect the development and yield of sweetpotato (p ≤ 0.05). Some studies suggest that differences may occur if the volunteer sprouts are compared with sprouts generated under optimal conditions.