Calculating the Threshold Temperature of Development for Weeds

Weed seeds were germinated in incubators at constant temperatures ranging from 4 to 32 C increments. Percent germination per day was regressed against temperature with the x-intercept representing the low threshold temperature for development. Low threshold temperatures for development (low TTD's) calculated for wild proso millet ( Panicum miliaceum L. # PANMI), barnyardgrass [ Echinochloa crus-galli (L.) Beauv. # ECHCG], common lambsquarters ( Chenopodium album L. # CHEAL), and redroot pigweed ( Amaranthus retroflexus L. # AMARE) were 6.9, 9.7, 6.0, and 10.0 C, respectively.