Effects of shading and soybean Glycine max (L.) interference on Solanum ptycanthum (Dun.) (eastern black nightshade) growth and development |
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Authors: | E. W. STOLLER R. A. MYERS |
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Affiliation: | U.S. Department of Agriculture, Agricultural Research Service, Department of Agronomy, 1102 South Goodwin, University of Illinois, Urbana, Illinois 61801;Department of Agronomy, University of Illinois, 1102 South Goodwin, Urbana, Illinois, 61801, U.S.A. |
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Abstract: | Summary. Solanum ptycanthum (Dun.) vegetative and reproductive growth was evaluated under shade and in the field with soybean interference. In full sunlight without soybean interference, a S. ptycanthum plant produced 243 g shoots and 5957 berries in 20 weeks, but only 38 g and 576 berries in 11 weeks. Plants grown in 94% shade produced 3 g of shoots and 23 berries in 20 weeks, and 1 g and 1 berry in 11 weeks. S. ptycanthum plants that emerged with the soybeans and were positioned between 75-cm rows produced 43 g shoots and 264 berries, whereas plants positioned in 75-cm rows and emerging 6 weeks after the soybeans produced 1 g and 16 berries. When grown between 37·5-cm rows for the same period of time this weed produced 12 g and 2 berries plant−1; plants positioned in 37·5-cm rows produced shoots less than 1 g in weight and one berry plant−1. Shoot growth and berry production of S. ptycanthum increased from 80 to 200% in a 2-week period between the initiation of soybean leaf abscission and maturity. In a season about 50 000 seeds weed−1 were produced in full sunlight; 20 000 or less were produced under soybean interference. When grown in irradiance levels from full sunlight to 94% shade, viable seeds were first detected 10 days after anthesis and essentially all seeds in the berry were viable 24 days after anthesis |
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