The goal of this research was to determine the effects of in-row spacing and planting time on yield and root grade of NC 98-608 over time. Two plantings were made in two grower locations (four total). An early planting was made 19 and 25 May and a late planting 19 and 24 June. NC 98-608 was evaluated at the following in-row spacings; 23, 31, 38, and 46 cm. `Beauregard' spaced at 23 cm in-row and was used as the standard comparison. Roots were harvested and graded into canner, number one, jumbo and cull grades 90, 105, and 120 days after planting for each of the planting dates and locations. Each grade was weighed. An early planting in late May resulted in roots reaching the highest percentage grade of U.S. number one roots as early as 100 days after planting, while the late planting in June resulted in roots never reaching their full number one yield potential in some cases. For an early harvest after planting (90 days after planting) the 38 cm in-row spacing produced the most marketable number one yields compared with the 23, 31, and 46 cm in-row spacings. For a later harvest time after planting (105 days or later), it appeared as though the 31 cm in-row spacing was the most economical spacing to use. Roots from the early plantings (late May) and finer textured soils appeared to have shorter roots than roots harvested from later plantings (after 15 June) or coarser textured soil. Root shape and yield was more uniform with NC 98-608 than with the Beauregard clone. With yields comparable to Beauregard, the NC 98-608 clone provides an excellent opportunity to produce a quality sweetpotato with consistent shape.
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