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

Yield Comparison between Conventional High Ridge Cultivation and Large Ridge Cultivation in Relation to Conventional Vine Planting and Tuber Seedling Transplanting of the Sweet Potato Cultivar ‘Murasakimasari’

“…In 2008, 60 to 100 g seed tubers of the sweet potato cultivar, 'Murasakimasari,' were cut in half at a right angle to the tuber's long axis, while seed tubers weighing 100-180 g were cut in half, and trimmed to remove excessive tissue from the cut surface, preparing cut tubers of approximately 30 to 50 g in fresh weight (Adachi et al 2011). The halved seed tubers are referred to as "half-cut" and those subsequently trimmed as "half-cut and adjusted."…”

“…Field Experiment 1 employed three plantings: CVP planted on April 30, TST1 transplanted on March 28, and TST2 transplanted on April 24. For TST1, total 883 of half-cut and adjusted tubers (36.8 ± 2.8 g) were incubated in eighteen trays under sunlit and temperature-controlled conditions at 25˚C in a glasshouse (Adachi et al 2011), and on March 27 (after 21 d incubation), 300 TSs (6 trays) were selected, and measured plant length (PL), stem length, and stem number. The measurements were as follows: average of PL 12.8 ± 6.4 cm (20 ≦ PL < 25 cm, 0.3%; 15 ≦ PL < 20 cm, 15.3%; 10 ≦ PL < 15 cm, 33.0%; 5 ≦ PL < 10 cm, 14.0%; 0 < PL < 5 cm, 9.0%; and PL = 0, 6.0%); stem length 6.5 ± 3.5 cm; and stem number per TS 4.5 ± 2.2.…”

“…Yield properties were compared between CHR and LAR cultivation using two planting modes, CVP and TST. Adachi et al (2011) reported that TST cultivation increased daughter tuber yield compared with CVP cultivation. Hence, we postulated that this high-yielding TST method might be suitable for new LAR cultivation modes.…”

“…This cultivar has primarily been cultivated to ferment the spirit, 'shochu. ' Adachi et al (2011) investigated the tuber seedling transplanting (TST) method within the cultivar 'Murasakimasari' and showed an enhancement in yield by this method over CVP.…”

“…In this study, we aimed to estimate the root tuber yield properties of the cultivar 'Murasakimasari' under the LAR conditions in comparison with the conventional high ridge conditions (CHR: RH, 33 cm; RID, 90 cm; RBW, 55 cm; and furrow, 35 cm), while also including the two planting modes of CVP and TST as another factor. We combined the estimation of yield properties of LAR and CHR cultivation with the two cultivation methods (CVP and TST), in order to justify the proposed use of the high yielding TST cultivation method (Adachi et al 2011), and include both ridge shape and planting method, by using a cultivar suitable for direct planting, 'Murasakimasari'.…”