Seed Biology of the Weed Maryland Meadowbeauty (Rhexia mariana L.) in Blueberry (Vaccinium spp.)

Studies were conducted at three locations across the North Carolina coastal plain region to determine sexual reproductive potential, seedbank density, frequency of seed dormancy, and effect of temperature on Maryland meadowbeauty seed germination. Seed capsule density ranged from 500 per m² to 1124 per m² across locations. Each capsule contained an average of 74 seeds. Seeds germinated only in the 35/20 °C temperature regime, which represents the hottest month (August) of the growing season in southeastern North Carolina. Total number of germinated seeds differed across locations and ranged from 30% to 57%. The percent (average) of viable (66) and nonviable (26) meadowbeauty seeds was not different across locations. Relative germination and seed dormancy percentages were calculated based on the number of viable seeds. The percent relative germination and seed dormancy were different across locations and ranged from 47% to 86% and 14% to 55%, respectively. The highest number of germination resulted from 90 days of stratification. On average, 27 seeds germinated among soil samples, which is equivalent to 989 seeds per m². The data indicate that the populations of meadowbeauty in blueberry fields have the potential to sexually reproduce and contribute 5 × 10⁶ to 1.1 × 10⁷ seed capsules/ha and 3.7 × 10⁸ to 8.3 × 10⁸ seeds/ha of infestation. Freshly mature seeds can germinate and contribute 1.79 × 10⁸ to 7.14 × 10⁸ seedlings/ha in the year the seeds are produced and 5.18 × 10⁷ to 4.4 × 10⁸ seeds/ha can be dormant and incorporated into the seed bank on an annual basis. Approximately 9.89 × 10⁶ seeds/ha are dormant and viable in the soil and have the potential to germinate following adequate stratification.