Dormancy and survival in buried seeds of proso millet (Panicum miliaceum)

Abstract

Survival, dormancy, and germination of buried seeds of 30 populations of proso millet (Panicum miliaceum L.) were investigated. The effects of duration and depth of burial and type of soil were considered. The 30 populations belong to three agronomic groups: crop, croplike weed, and black-seeded weed. Black seeds exhibited much greater overwinter survival and dormancy than did seeds of the other two groups. Crop seeds had almost no survival through the winter. Only one croplike weed population exhibited appreciable (13–40%) survival after one winter in the soil. A combination of endogenous and enforced dormancy in black seeds effected an adaptive germination pattern of little (1%) germination at both the surface and 20 cm deep and much greater (40%) germination at 5 cm deep. Surviving crop and croplike weed seeds germinated irrespective of position in or on the soil. In a longer term experiment with only three populations both the croplike weed and black-seeded populations survived best in a well-drained soil. For the black-seeded population greater germination in the well-drained soil depleted that seed bank earlier than those in the medium-drained or poorly drained soils. The crop and croplike weed populations produced only transient seed banks in all three soil types, whereas some black seeds survived for 4 years.