Inheritance of resistance to diclofop-methyl and fenoxaprop-p-ethyl in two Avena sativa × A. fatua populations

Abstract

Since the late 1980s, several reports of herbicide-resistant wild oat have raised concern about potential weed control problems in western Canada. This study was conducted to determine the mode of inheritance, number of genes and type of gene action governing herbicide resistance in two Avena sativa × A. fatua crosses. The herbicide-susceptible A. sativa cultivars, Random and Derby, were crossed with a resistant A. fatua genotype, GP-HR-01. Parents, F2s and F2:3 families were tested for their reactions to two post-emergent wild oat herbicides, diclofop-methyl and fenoxaprop-p-ethyl, in the greenhouse. Inheritance of resistance to diclofop-methyl and fenoxaprop-p-ethyl was dominant and monogenic in the Derby/GP-HR-01 cross, but was controlled by two dominant complementary genes in the Random/GP-HR-01 cross. Resistance to both herbicides appeared to be controlled by the same genes or groups of tightly linked genes. Key words:Avena sativa, Avena fatua, herbicide resistance, weed (genetics), diclofop-methyl, fenoxaprop-p-ethyl