Giant foxtail (Setaria faberi) outcrossing and inheritance of resistance to acetyl-coenzyme A carboxylase inhibitors

Abstract

Gene flow via pollen and inheritance of acetyl-coenzyme A carboxylase (ACCase) inhibitor resistance in giant foxtail have not been previously characterized. Therefore, experiments were conducted to quantify outcrossing rates and flowering periods of giant foxtail accessions resistant or susceptible to ACCase inhibitors and to determine the inheritance pattern of gene(s) that confer resistance. In greenhouse experiments, outcrossing rates between resistant and susceptible parents ranged from 0.24 to 0.73%, as gauged by the response of F1 plants to fluazifop-P. Resistant plants and susceptible plants flowered at similar times, with peak flowering occurring 63 to 67 d after planting. During this period, flower initiation was nearly twice as great for resistant plants as for susceptible plants. In inheritance experiments F2 plants segregated in a 1:2:1 ratio of resistant–intermediate–susceptible phenotypes after exposure to fluazifop-P, indicating that resistance was associated with a single nuclear, incompletely dominant allele. The very low rates of outcrossing among giant foxtail plants in the greenhouse indicate that gene flow of resistance traits in the field is likely to occur primarily by seed immigration rather than by pollen movement. However, gene flow of herbicide resistance traits via pollen provides a mechanism in which multiple resistance may develop among giant foxtail populations that are resistant to other classes of herbicides.

Inheritance of resistance to fenoxaprop‐p‐ethyl in sprangletop (Leptochloa chinensis L. Nees)

“…), annual ryegrass (Tal & Rubin ; Tardif et al . ), giant foxtail (Volenberg & Stoltenberg ), green foxtail ( Setaria viridis ) (Stilkowski ) and foxtail millet (Wang & Darmency ).…”

“…The F 1 hybrids of sprangletop were produced satisfactorily by outcrossing between the resistant and the susceptible genotypes and were screened in the presence of fenoxaprop‐p‐ethyl. The same method has been used in giant foxtail (Volenberg & Stoltenberg ) and black grass (Petersen et al . ).…”

“…Resistance to diclofop‐methyl in wild oat ( Avena fatua L.) (Seefeldt et al . ), giant foxtail ( Setaria faberi ) resistance to fluazifop‐p‐butyl (Volenberg & Stoltenberg ) and ryegrass ( Lolium rigidum ) (Tardif et al . ) resistance to haloxyfop–ethoxyethyl and ACCase‐inhibiting herbicides (Tal & Rubin ) have been found to be controlled by a single nuclear gene.…”

The Biology of Canadian Weeds. 141. Setaria faberi Herrm.

“…In a similar study, S. faberi cross resistance to fluazifop-P-butyl was identified in a vegetable cropping system in Wisconsin where the resistant biotype was 10.6-and 319-fold more resistant than the susceptible biotype (Volenberg and Stoltenberg 2002a). Greenhouse experiments have shown that the outcrossing rates between ACCase susceptible and ACCase resistant parent plants are low and range from 0.24 to 0.73% (Volenberg and Stoltenberg 2002b).…”

“…Generally, dry weight production decreases linearly with increases in shade levels (Santelmann et al 1963;Knake 1972). Peak flowering of greenhouse-grown S. faberi plants in Wisconsin occurred 63 to 67 d after planting of seeds (Volenberg and Stoltenberg 2002b). In abandoned fields in Illinois, S. faberi populations showed a bimodal pattern of seed germination where the densities of the populations first peaked in May and then in July/August (Raynal and Bazzaz 1975).…”