title: Investigation of MCPA (4-Chloro-2-ethylphenoxyacetate) resistance in wild radish (Raphanus raphanistrum L.).
abstract: The phenoxy herbicides (e.g., 2,4-D and MCPA) are used widely in agriculture for the selective control of broadleaf weeds. In Western Australia, the reliance on phenoxy herbicides has resulted in the widespread evolution of phenoxy resistance in wild radish (Raphanus raphanistrum) populations. In this research the inheritance and mechanism of MCPA resistance in wild radish were determined. Following classical breeding procedures, F1, F2, and backcross progeny were generated. The F1 progeny showed an intermediate response to MCPA, compared to parents, suggesting that MCPA resistance in wild radish is inherited as an incompletely dominant trait. Segregation ratios observed in F2 (3:1; resistant:susceptible) and backcross progeny (1:1; resistant to susceptible) indicated that the MCPA resistance is controlled by a single gene in wild radish. Radiolabeled MCPA studies suggested no difference in MCPA uptake or metabolism between resistant and susceptible wild radish; however, resistant plants rapidly translocated more (14)C-MCPA to roots than susceptible plants, which may have been exuded from the plant. Understanding the genetic basis and mechanism of phenoxy resistance in wild radish will help formulate prudent weed management strategies to reduce the incidence of phenoxy resistance.
authors.affiliation: Department of Agronomy, Kansas State University , Manhattan, Kansas 66506, United States.
authors.forename: Mithila
authors.initials: M
authors.lastname: Jugulam
authors.forename: Natalie
authors.initials: N
authors.lastname: Dimeo
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Veldhuis
authors.forename: Michael
authors.initials: M
authors.lastname: Walsh
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Hall
mesh_terms: D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000378:metabolism / Q000494:pharmacology*; D001947:Breeding; D053209:Herbicide Resistance; D006540:Herbicides / Q000378:metabolism / Q000494:pharmacology*; D031224:Raphanus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D014904:Western Australia
chemical_list: D006540:Herbicides; D008456:2-Methyl-4-chlorophenoxyacetic Acid