| Abstract: | Plants from two black nightshade (Solanum spp.) seed sources were compared for differences in morphology at seedling and mature plant stages, flowering and physiological responses to pre-germination seed treatment, growth responses to temperature, and response to herbicides. Differences in the morphology of the two Solanum spp. were evident from seedling to maturity. The plants grown from the Michigan (MI) seed source had a deep purple abaxial leaf surface at the three to four-leaf stage, a yellow anther column, and toothed proximal half in the mature leaf, whereas the plants grown from the California (CA) seed source had no unusual abaxial coloration or toothed proximal margin and had a dark brown anther column. Differences in response to herbicides were seen between plants grown from the two seed sources following pre-plant-incorporated, pre-emergence, and post-emergence herbicide applications. The plants from the MI seed source were up to five times more susceptible to chloramben, applied pre-plant-incorporated at 1.68 kg ha?1, and to ethalfluralin, applied preemergence at 1.12 kg ha?1, than plants from the CA seed source. Plants from both seed sources have been described as Solanum nigrum L. The plants from MI have been identified elsewhere as Solanum ptycanthum Dun. and those from CA as Solanum scabrum Mill. This identification could resolve conflicting reports among researchers regarding chemical control measures. |
