Field emergence and temperature requirements for germination in Solanum sarrachoides Sendt.

Summary Emergence of Solanum sarrachoides began in late April, reached a peak in May or June and ceased in September. This pattern closely resembled that for S. nigrum L., whereas almost all seedlings of S. dulcamara L. emerged in April. Fresh seeds of S. sarrachoides were dormant but developed a capacity for germination at 25 and 30°C and at alternating (16 h low/8 h high) temperatures of 4/25, 10/25, 10/30 and 20/30°C when stored dry. kept moist at 4°C or buried in the field. Buried seeds also became capable of germinating at 10. 15 and 20°C and the temperature range for germination was widest during April‐June. Induced dormancy developed during August and the range narrowed. The consistent seasonal emergence pattern appears to be associated with cyclic changes in the dormancy status of buried seeds.