Publication Date
1993
Description
Diclofop ( (:t)-2-[4-(2,4 • dichlorophenoxy) phenoxy] propanoic acid} has been used to control annual grasses in cereals since 1980 in the Willamette Valley of Oregon, USA. Populations of Italian ryegms (Lolillm multiflorum Lam.) resistant to diclofop were recently discovered. Progenies from resistant plants crossed with plants from the susceptible cvs. Marshall and Gulf were sib-mated and backcrossed to Marshall or Gulf. Resultant F2 and backcross families were screened for survival when sprayed with 1.4 kg/ha diclofop-methyl. Segregation ratios of live to dead plants showed that resistance is determined by 2 genes when a dominant allele is present at each locus. Frequency of survival was determined by treating plants from 12 cultivars not previously exposed to the herbicide. All cultivars had some surviving plants, but average survival in 2 tests was less than I%. Frequency of plant survival within cultivars further supported the multiple-loci genetic model for diclofop resistance in Italian ryegrass.
Citation
Barker, R E.; Mueller-Warrant, G W.; Griffith, S M.; and Banowetz, G M., "Characterization of Genetic Resistance to Diclofop in Italian Ryegrass" (2024). IGC Proceedings (1993-2023). 18.
https://uknowledge.uky.edu/igc/1993/session12/18
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Characterization of Genetic Resistance to Diclofop in Italian Ryegrass
Diclofop ( (:t)-2-[4-(2,4 • dichlorophenoxy) phenoxy] propanoic acid} has been used to control annual grasses in cereals since 1980 in the Willamette Valley of Oregon, USA. Populations of Italian ryegms (Lolillm multiflorum Lam.) resistant to diclofop were recently discovered. Progenies from resistant plants crossed with plants from the susceptible cvs. Marshall and Gulf were sib-mated and backcrossed to Marshall or Gulf. Resultant F2 and backcross families were screened for survival when sprayed with 1.4 kg/ha diclofop-methyl. Segregation ratios of live to dead plants showed that resistance is determined by 2 genes when a dominant allele is present at each locus. Frequency of survival was determined by treating plants from 12 cultivars not previously exposed to the herbicide. All cultivars had some surviving plants, but average survival in 2 tests was less than I%. Frequency of plant survival within cultivars further supported the multiple-loci genetic model for diclofop resistance in Italian ryegrass.
