INVESTIGADORES
VILA AIUB Martin Miguel
congresos y reuniones científicas
Título:
Selection of glyphosate-susceptible and resistant plants in Echinochloa colona for the study of fitness costs associated with resistance
Autor/es:
GOH, S.S.; VILA AIUB, MM; BUSI, R.; POWLES, SB
Reunión:
Conferencia; Global Herbicide Resistance Challenge Conference; 2013
Institución organizadora:
Australian Herbicide Resistance Initiative
Resumen:
When assessing fitness costs associated with herbicide resistance, it is
crucial to ensure that herbicide susceptible (S) and -resistant (R) individuals
share a similar genetic background, except for the herbicide resistance
alleles. Glyphosate resistance has evolved in Echinochloa colona populations from WA cropping systems and we
intend to determine the existence of associated fitness costs. A plant cloning
technique followed by phenotypic identification after glyphosate selection is
the experimental approach that is being used to identify S and R plants within
a segregating glyphosate resistant E.
colona population. For selection of R plants, seeds were sown in trays and
at the two- to three-leaf stage, seedlings were treated with 2,160 g ha-1
of glyphosate (Roundup 540 g a.i. L-1). Plant survival was recorded
two weeks after glyphosate treatment and surviving plants (27 out of 100
plants; 27.0%) were classified as R plants. For selection of S plants, about 89
plants were cloned and numbered. When the clones achieved two- to three-leaf
stage, they were sprayed with 300 g ha-1 of glyphosate (Roundup 540
g a.i. L-1). Twenty five seedlings did not survive the glyphosate
treatment (25 out of 89, 28.1%) and were classified as S plants. All identified
S and R plants were grown outdoors until reproduction. Enclosures were built to
prevent pollen contamination from other sources. Further glyphosate resistance
verification of homogeneous S and R individuals from within both
sub-populations were conducted after selection with glyphosate field
recommended rate (Roundup 540 g a.i. L-1). Subsequently, seeds from
each S and R individuals were bulked and served as the plant materials for
whole-plant-dose response studies at controlled environmental room and
evaluation of fitness costs associated with glyphosate resistance in E. colona. This glyphosate-resistant E. colona was found to be 4.7-fold more
resistant to glyphosate than the susceptible population. Based on biomass, the
resistance index was 5.7. Besides, EPSPS gene sequencing was also studied and
the mutations in the EPSPS gene known to confer glyphosate resistance in other
species are not present in this glyphosate resistant E. colona population.