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Variation in Seed Weight and Germination in Populations of Amaranthus Retroflexus L.
Author(s) -
McWilliams E. L.,
Landers R. Q.,
Mahlstede J. P.
Publication year - 1968
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1934458
Subject(s) - germination , dormancy , biology , weed , seed dormancy , agronomy , latitude , botany , ecology , horticulture , geography , geodesy
Amaranthus retroflexus L. seeds were harvested from plants grown under uniform conditions in Ames, Iowa, from seeds collected in North America and eastern Europe. Germination of seeds from northern populations was significantly higher at 20°C than that from southern populations at the same temperature. Germination percentages were highest in all cases at 35 o C. No correlation was found between percentage germination at 35°C and latitude, but there was wide variation between populations in germination response. Populations from the drier parts of the United States tended to show greater dormancy. This weed species does not appear to have a characteristic dormancy and germination, requirement over its range. Variations in germination percentage between populations at either temperature were concluded to be a result of ecological differentiation. Seed weight decreased significantly from northern to southern sources. Larger seeds and the ability to germinate at lower temperatures may be of selective advantage in northern populations where this annual species must mature in a short growing season.