The relative competitiveness of atrazine susceptible and resistant populations of Chenopodium album and C. strictum

Abstract

The total aboveground biomass and reproductive dry weight of 1 atrazine resistant and 1 susceptible population from southern Ontario [Canada] of both C. album and C. strictum were compared. The comparison was made between plants grown under noncompetitive and competitive conditions. Results from a spaced noncompetitive trial provided evidence for greater total and reproductive biomass production and earlier flowering of resistant and susceptible populations of C. album as compared with both populations of C. strictum, greater aboveground total and reproductive biomass production of the susceptible population of C. album as compared with the resistant population and greater total aboveground biomass production (but similar reproductive biomass) of the susceptible population of C. strictum as compared with the resistant population. Results from the competition trials (i.e., plants grown in a de Wit replacement series), provided evidence for inter- and intra-specific differences in competitive ability: the susceptible population of C. album was more competitive than the susceptible population of C. strictum, the susceptible population of C. album was a superior competitor to the resistant population and the resistant and susceptible populations of C. strictum apparently were equally competitive.