On the variability of cleavers (Galium aparine)
1988
Niemann, P. (Biologische Bundesanstalt fuer Land- und Forstwirtschaft, Braunschweig (Germany, F.R.). Inst. fuer Unkrautforschung)
Seeds of Galium aparine from arable and nonarable locations in North Germany were collected and the generated plants were tested in comparative studies for variability in the following plant characteristics: shape of cotyledones, shape of leaves, length of shoots, length of internodes, weight of shoots, and dormancy of seeds. The results confirm the existence of field and nonfield ecotypes of the weed. The shape of cotyledones was found to be the most constant characteristic for differentiating between ecotypes. The cotyledones of field ecotypes were elliptical-lanceolate while those of nonfield ecotypes were elliptical. In comparative studies the field ecotypes grew faster, showed an errect growth habit, and flowered earlier than the nonfield ecotypes. Nitrogen fertilization and herbicide treatments with mecoprop and ethofumesate had the same effect on all samples. This suggests that insufficient herbicide efficacy in the field must be primarily due to the environmental factors. It is concluded that the genetically fixed variability of plant characteristics should be considered in experimental work with weeds by critical selection and precise description of the test material
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