A comparison of seedling vigour in crop and weed biotypes of proso millet (Panicum miliaceum)

Three groups (weed, eroplike weed, crop) of proso millet (Panicum miliaceum L.) which vary extensively in seed size and colour were used in a series of experiments to compare their seedling vigour and rates of germination. It was found that greater seed size, lack of seed dormancy, and greater seedling vigour occurred in the crop and croplike weed biotypes. Further, the growth rates of the three groups were similar, and hence most differences in seedling vigour among biotypes resulted from dissimilar seed weights. Several previous studies on other species had shown that seed weight and seedling growth rates were negatively correlated (thus, initial seed size differences would not persist to maturity) and the relationship between those results and ours is discussed. Also, regeneration strategies within a species for both crops and weeds are discussed from an evolutionary point of view.