Supplemental lighting spectrum impact on sweet potato cutting production and rooting

Abstract

AbstractLight is an important factor in plant growth and morphology of sweet potato (Ipomoea batatas L. Lam). This study explored the impact of supplemental lighting provided by three commercially available units on a stock plant cutting production and cutting rooting of two sweet potato cultivars ‘Covington’ and ‘Beauregard’. In experiment one, stock plants were grown under one of four lighting conditions, no supplemental light, high blue light emitting diode (LED), low blue LED, or halogen. Cuttings were collected twice a week for 5 wk and the total weekly cutting number and cutting caliper per plant were recorded. During this experiment plants grown under supplemental lighting exhibited significantly greater weekly total cutting numbers after 2 wk of growth when compared with those that were not exposed to supplemental lighting. In experiment two, cuttings were rooted under the same four light treatments and sampled on Days 7, 14, and 21 in which the cutting height, root weight, and shoot weight were recorded. On Day 21 Covington plants grown under low blue and halogen supplemental lighting exhibited significantly greater root dry weight when compared with those that did not receive supplemental lighting. However, no differences in rooting were observed for Beauregard. These results demonstrate that supplemental light increases stock plant growth regardless of the three commercially available light spectrums examined when compared with no supplemental light. This suggests that increasing the daily light integral (DLI) has a larger impact on plant growth than the spectrum of the commercially available lights that were examined.