Yield and Growth of Sweetpotato Using Plug Transplants as Affected by Their Ages and Planting Depths

Abstract

The yield and growth of sweetpotato using plug transplants with roots and 3–6 unfolded leaves were compared with those of sweetpotato using conventional cuttings without roots and with 7–8 unfolded leaves (Control). The plug transplants were produced under artificial light using single node cuttings each with one unfolded leaf. The plug transplants of 11- and 15-day old were planted with 1 and 3 nodes inside the soil ridges (called 1- and 3-node depth, respectively, hereafter) to find out the optimum age of transplants and optimum depth of planting for higher yield of sweetpotato. The yield of storage roots 115 days after planting in the field was 40 ton ha-1 when using 15-day old transplants planted with 3-node depth and was 17 ton ha-1 greater than that in the Control. The number of storage roots per plant was 4.7 when using 11-day old transplants planted with 3-node depth and was 1.6 greater than that in the Control. The percent harvest index on day 115 was 81% when using 15-day old transplants planted with 3-node depth. The overall performance of the plug transplants was significantly higher than that of the conventional cuttings. The plug transplants planted with 3-node depth showed higher overall performance than did the plug transplants planted with 1-node depth.