Germination and growth of Solanum ptycanthum and Solanum sarrachoides

Abstract

The distribution and abundance of hairy nightshade (Solanum sarrachoides Sendt.) has been increasing relative to that of eastern black nightshade (Solanum ptycanthum Dun.) in cultivated fields in southern Ontario. The germination and early growth of the two species were compared under controlled environmental conditions. Individual seeds of hairy nightshade weigh almost twice as much as those of eastern black nightshade. Time to 50% germination of seeds of hairy nightshade was faster over a range of temperatures, and total germination in the dark and at low temperature was greater compared to seeds of eastern black nightshade. Seedlings of hairy nightshade also grew faster than those of eastern black nightshade, having greater height, leaf number, and aboveground dry weight at 10 and 21 d after emergence in growth chambers at 28/20 and 22/14 °C. Individuals of hairy nightshade began to reproduce earlier with a consequent decrease in vegetative growth. By 35 d after emergence, leaf area and aboveground dry weight of seedlings of eastern black nightshade equalled or exceeded those of hairy nightshade. Differences between species were consistent for populations from two separate locations in Ontario. Key words: Germination, eastern black nightshade, hairy nightshade