Soil-less bioassays for early screening for resistance to imazapyr in sunflower (Helianthus annuus L.).
BACKGROUND
Rapid and efficient diagnostic tests for early screening of herbicide resistance are convenient alternatives to field screening methods. There is a need for a quick, reliable and cost-effective method for rapid diagnosis of imidazolinone resistance in sunflower (Helianthus annuus L.).


RESULTS
Two seed germination bioassays were developed. Seeds from three sunflower inbred lines differing in resistance to imidazolinones were germinated either on solid culture medium or placed in plastic pots filled with commercial perlite. After 8 days incubation under controlled conditions, both assays successfully distinguished susceptible genotype from the resistant and intermediate ones. The susceptible genotype showed arrested root growth at all herbicide treatments (root length < 1 cm). The resistant genotype developed a complete root system even when exposed to the highest dose of herbicide. However, no definite differences were observed for the intermediate and resistant genotypes with respect to root growth under the different herbicide treatments.


CONCLUSIONS
The simple and rapid screening assays described in the present study were useful in discriminating imidazolinone resistance at the seedling stage. Therefore, these bioassays could be potential tools for early screening of imidazolinone resistance genes from large sunflower populations.
Vega
Tatiana
T
Cátedra de Genética, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental JF Villarino, CC 14, S 2125 ZAA Zavalla, Argentina.
Breccia
Gabriela
G
Nestares
Graciela
G
Mayor
María Laura
ML
Zorzoli
Roxana
R
Picardi
Liliana
L
D001681:Biological Assay / Q000379:methods*; D005838:Genotype; D018525:Germination / Q000187:drug effects; D006368:Helianthus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D009525:Niacin / Q000031:analogs & derivatives* / Q000494:pharmacology
D006540:Herbicides; D007093:Imidazoles; D009525:Niacin; C076656:imazapyr