|Jackson, David - Mike|
Submitted to: American Society for Horticultural Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/5/1999
Publication Date: N/A
Technical Abstract: Polycross seed nurseries are commonly used in breeding programs for sweetpotato, Ipomoea batatas (L.) Lam. However, because of the dependence on native insect pollinators, the male parents of F1 progeny are not known; and little has been reported about pollinators of sweetpotatoes. Sweetpotato entries may flower at different times and have different amounts of nectar, which could influence bee visitations. Therefore, knowledge about the flowering cycles of individual sweetpotato entries and their synchrony with native insect pollinators could be important to maintain efficient polycross nurseries. We monitored sweetpotato flowering patterns and pollinators in polycross seed nurseries at Charleston, SC, 1996-98. In 1996, 27 sweetpotato lines were grown in four single-plant replications in one field. Plants were monitored once a week between 10:00-12:00 AM from mid-June to mid-December. At each sampling, all open flowers and associated insects were counted, and sample specimens were collected for identifications. For 1997, 8 breeding lines (W-125, W-263, W-272, W-278, W-302, W-306, W-316, and W-317) were grown in 3 fields with 4 plants of each entry. These lines had a wide range of total flowers and onset of flowering. W-272 and W-278 could not be grown in 1998, so W-235 W-296 were substituted. The total number of flowers for all lines ranged 0.6 to 78.0 flowers/plant/sampling date. At least 4 species of bumble bees, Bombus spp., were the primary pollinators, and their presence was highly synchronized with flowering. No honey bees, Apis mellifera L., were observed until late in the season (November) after other pollen sources were no longer available. Few other pollinators were observed.