Nurturing of Plantlets Using Cut Pieces from the Storage Roots of Sweet Potatoes (Ipomoea batatas(L.) Lam.) and their Productivity in the Field

Root Piece Planting in Sweetpotato—A Synthesis of Previous Research and Directions for the Future

“…Germplasm was screened for root piece planting ability Kays and Stutte (1982) United States Examined the effect of cutting of root pieces and root piece size on the outcome of root piece planting Bouwkamp (1982) United States Examined the effect of presprouting treatments and fungicide on root piece planting. Describe selection methodology for varieties adapted to root piece planting Jeong et al (1986) Korea Compared the effect of different nutrient regimes and planting times Hosokawa et al (1998) Japan Built and tested a self-propelled semiautomatic seed piece planter Yamashita (2000) Japan Studied the effect of different hormone treatments on the sprouting and root growth of root pieces Kubota et al (2000) Japan Compared time and cost saving between planting systems using root pieces and slips Arima et al (2002) Japan Studied the effect of different hormone treatments on the sprouting and root growth of root pieces Bowen (2010) United States Examined the effect of cutting on sprouting and yield from root pieces and estimated the heritability of traits important to root piece planting Fig. 1.…”

“…There is a strong positive correlation between the size of a sweetpotato root piece and the extent to which it enlarges; smaller pieces result in reduced enlargement (Kodoma, 1962;Nakazawa, 1973;Nakazawa and Sano, 1969). Smaller root pieces also exhibit reduced sprouting relative to larger ones though (Takatori, 1961;Yamashita, 2000), so smaller roots are prone to reduced stand establishment. So a tradeoff exists between planting a root piece small enough to minimize enlargement but large enough to allow sufficient sprouting for establishment.…”

“…So a tradeoff exists between planting a root piece small enough to minimize enlargement but large enough to allow sufficient sprouting for establishment. The ideal root piece size appears to vary between varieties, but is %40 to 60 g (Kodoma, 1962;Yamashita, 2000), although some workers report success with pieces of around 20 g under field conditions (Bouwkamp, 1982).…”

“…The use of plant hormones as a method to promote sprouting and root growth of planted root pieces has been investigated (Arima et al, 2002;Yamashita, 2000). Yamashita (2000) explored the use of a number of common plant hormones on small (1 to 10 g) sweetpotato root pieces and found that, relative to controls, rooting was increased significantly, from 0% to 50% of pieces, after treatment with 100 mgÁL -1 indole-3-acetic acid, and shoot growth was increased 2.8 times relative to controls with 5 mgÁL -1 abscisic acid. Yields of storage roots from treated pieces in this work were comparable to the yield obtained from slips.…”

Transplantation of Half-Cut Tuber Seedlings Provides Enhanced Yields Over Conventional Sprouted-Vine Planting in Sweet Potato Cultivar “Murasakimasari”

“…Direct tuber planting has several advantages over conventional vine planting, including energetic growth of plants, high yield from widely spaced planting, and resistance to environmental stresses (Sakai, 1999), but has not been widely adopted. Yamashita (2000) and Arima et al (2002) studied a new method using cut pieces of tubers. New cultivars suitable for direct planting, "Murasakimasari" and "Tamaakane", were released in 2004 and 2009, respectively (Sakai et.…”