Variation among 21 Populus clones in tolerance to simazine and diuron

Abstract

Clones of 21 cultivars from Populus sections Aigeiros and Tacamahaca were grown from cuttings in a greenhouse and assayed for tolerance to five dosages of simazine and diuron using a sand-eulture technique. Individual clones differed in their response to increasing dosages of the two herbicides. Each clone was classified as tolerant, intermediate, or intolerant to simazine and diuron based on the dosage required to cause a 20% reduction in plant dry weight (ED20). Pure Tacamahaca hybrids and intersectional crosses between Tacamahaca and Aigeiros were relatively intolerant of both herbicides. Pure Aigeiros clones were relatively tolerant to simazine and diurion, but even these clones were severely injured or killed by the highest dosages.