Skip to main content
ARS Home » Research » Publications at this Location » Publication #70138
Title: EFFECTS OF TEMPERATURE AND PHOTOPERIOD ON TROPICAL SODA APPLE (SOLANUM VIARUM) AND ITS POTENTIAL RANGE IN THE UNITED STATES

Author
item Patterson, David
item MCGOWAN, MIKE - DUKE UNIVERSITY
item MULLAHEY, J - UNIV. OF FLORIDA

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Tropical soda apple is an exotic invasive weed from South America which has become a serious problem in improved pastures and rangelands in Florida. We conducted controlled-environment experiments on factors controlling its growth and development, in order to predict its potential ecological range and agricultural impact in the United States. Day length had little effect on tropical soda apple except for a reduction of plant height in the shortest (8-hr) day. Artificially pollinated plants set fruit and produced germinable seeds in day/night temperature regimes ranging from 23/17 to 32/26 C. Maximum growth occurred at day/night temperatures of 24/26 to 36/26 C. Plants survived at 18/8 C, but growth was reduced 100-fold or more. A regression equation to predict the percent of maximum growth of tropical soda apple during each month from March through November at diverse sites throughout the United States indicated that temperatures at sites throughout the South and lower Midwest would allow 30% or more of maximum growth to occur from at least May through September. Further north and west, growth would be more seasonally restricted. Action should be taken as soon as possible to eradicate or contain current infestations and limit further spread of this noxious weed.

Technical Abstract: In experiments to determine its environmental requirements and potential range, the exotic invasive weed, tropical soda apple (Solanum viarum) was grown in the 16 day/night temperature regimes available in all combinations of four controlled-environment chambers programmed for day/night temperatures of 18/8, 24/14, 30/20, and 36/26 C. Maximum height, leaf area, and shoot biomass occurred at day/night temperatures ranging from 24/26 to 36/26 C. Plants survived at 18/8, 24/8, 30/8, and 36/8 C, but biomass and leaf area were only 3 to 10% of maximum. Flowering was delayed by photoperiods of less than 10 h, but occurred within 60 days after emergence in photoperiods ranging from 8 to 16 h. Artificially pollinated flowers produced fruit with germinable seeds within 6 to 7 weeks, at temperatures ranging from 23/17 to 32/26 C. A regression equation relating growth to temperature indicated that tropical soda apple could achieve 30% or more of its maximum growth rate during 5 to 7 months of the year throughout the southern and lower midwestern United States. Neither temperature nor photoperiod will limit the further spread of the weed in these areas.