INTRASPECIFIC VARIATION IN GERMINATION REQUIREMENTS AND GROWTH IN AMARANTHUS DUBIUS

Seeds collected from five Amaranthus dubius plants of the same population were weighed and tested in continuous light or darkness at three temperatures in controlled conditions. Different seed families differed in weight, germination percentages and rate, and responded differently to an increase in temperature from 25 to 38 C. Plants derived from these seed families and grown outdoors, either singly or in mixtures, differed in several growth characteristics and in time to flowering. Significant interactions between growth characteristics and growth conditions, as measured with a two-way ANOVA, suggest that plants derived from different individuals differ in their competitive ability. The progeny of different individuals may thus be favored in different environmental conditions.