Abstract
Nine sweetpotato cultivars were evaluated in six bimonthly plantings on a Coto clay (Oxisol) to determine effect of planting season on yields. All crops were harvested 5 months after planting. The tests included the white-fleshed cultivars Miguela, Mina, Chardón, Ponceña, and Blanquita, and the yellow-fleshed Gem, Cobre, L 963-3, and R 59-36. Maximum yields of roots, either white- or yellow-fleshed, were obtained from November 1973 plantings. Yields from March or May 1974 plantings generally were low. Of the white-fleshed cultivars, Miguela and Mina were consistently high yielders. Peak yields from cultivars Ponceña and Blanquita were obtained from November 1973 plantings and low yields from July 1973 and May 1974 plantings. Chardón made poor yields throughout the year. Gem produced high yields throughout the year and seemed to be less photosensitive than the other three yellow-fleshed cultivars. Cultivar R 59-36 seemed most affected by day-length with peak yield from the November planting and the lowest yield in the May 1974 plantings. Cultivar L 963-3 made good yields throughout the year. Cobre made lowest yield from July 1973 planting and peak yield was obtained from November planting.