Inheritance of Resistance to Clopyralid and Picloram in Yellow Starthistle (Centaurea solstitialis L.) Is Controlled by a Single Nuclear Recessive Gene

Abstract

The noxious weed yellow starthistle (Centaurea solstitialis L.) can be controlled effectively at the seedling stage with foliar application of the auxinic herbicides picloram or clopyralid. Although resistance to these herbicides is rare, a yellow starthistle biotype resistant to picloram and cross-resistant to clopyralid was observed in 1989 near Dayton, WA, in a pasture that had been subjected to intensive picloram selective pressure. Our objective was to determine the mode of inheritance for this resistance trait. Transmission of the resistant phenotype was monitored in reciprocal F(1) crosses between susceptible (SCI) and resistant (RDW) plants, their testcross and pseudo-F(2) progeny. Progeny from all crosses, as well as RDW and SCI seedlings of original populations, were sprayed with picloram or clopyralid to distinguish between susceptible and resistant individuals. All F(1) progeny were susceptible to both herbicides, indicating that the resistance trait was of nuclear origin and recessive in nature. Segregation of the resistant phenotype among pseudo-F(2) and testcross progeny of F(1) genotypes demonstrated monofactorial inheritance (P >.25) for resistance to both herbicides. The conclusion that resistance is conferred by a single recessive allele is consistent with the observation that no other picloram-resistant yellow starthistle populations have been identified in the area since picloram selection pressure was abated.

Mutations in an Auxin Receptor Homolog AFB5 and in SGT1b Confer Resistance to Synthetic Picolinate Auxins and Not to 2,4-Dichlorophenoxyacetic Acid or Indole-3-Acetic Acid in Arabidopsis

“…However, an isolated occurrence of field resistance to picolinate auxins has been documented in yellow starthistle (Centaurea solstitialis) and appears to have arisen from heavy localized use of picloram. This resistant biotype carries a recessive mutation (Sabba et al, 2003) that confers selective resistance to picloram and clopyralid, but not to 2,4-D, and it also has normal growth and morphology (Fuerst et al, 1996). Thus, the picloramresistant field biotype appears to have some of the characteristics associated with the mutations that we have identified in Arabidopsis.…”

Evolution of Resistance to Auxinic Herbicides: Historical Perspectives, Mechanisms of Resistance, and Implications for Broadleaf Weed Management in Agronomic Crops

“…In addition, dicamba resistance in kochia (Kochia scoparia L.; biotypes from Henry, Nebraska) is determined by a single allele with a high degree of dominance (Preston et al 2009). Conversely, a single recessive gene controls clopyralid and picloram resistance in yellow starthistle (Centaurea solstitialis L.) (Sabba et al 2003) and quinclorac resistance in false cleavers (Galium spurium L.) (Van Eerd et al 2004). It has been reported that two additive genes control MCPA resistance in common hempnettle (Galeopsis tetrahit L.) (Weinberg et al 2006).…”

Understanding Genetics of Herbicide Resistance in Weeds: Implications for Weed Management

“…The cases of recessive gene inheritance of herbicide resistance are rare and limited to few herbicide chemistries. Not surprisingly, these cases have been reported in primarily self-pollinating species (except picloram and clopyralid resistance in yellow starthistle), and the examples include trifluralin resistance in green foxtail [11], quinclorac resistance in false cleaver [12], picloram and clopyralid resistance in yellow starthistle [13], as well as triallate resistance in wild oats [14].…”