IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The evolutionary ecology of resistance to herbicides: insights into the role of plant fitness
Autor/es:
VILA AIUB, MM; BUSI, R.; POWLES, SB
Reunión:
Conferencia; Global Herbicide Resistance Challenge Conference; 2013
Institución organizadora:
Australian Herbicide Resistance Initiative
Resumen:
An evolutionary and ecological
theoretical framework for improving the understanding of herbicide resistance
in plants is formulated. Considering the evolutionary ecology of herbicide
resistance in agro-ecosystems requires the assessment of plant fitness (W) of herbicide resistant (R) and susceptible (S) genotypes in the presence (WR(h), WS(h))
and absence (WR, WS) of herbicide selection.
Two conditions must be met for resistance to evolve: a herbicide resistance
trait must endow a fitness (W)
advantage over the wild type under herbicide (h) selection (i.e. resistance
benefit, RB), and this advantage should exceed any fitness or ecological
disadvantage associated with the resistance trait in the absence of herbicide
selection (i.e. resistance cost, RC).
Provided a positive net fitness difference (RB>RC), then rapid herbicide resistance
evolution is possible, especially if the resistance traits endow a significant
fitness benefit under herbicide selection and show no or negligible resistance cost in the absence of
herbicide selection. The fitness difference (RB>RC) informs about the occurrence probability of resistance evolution
and the magnitude of the difference has been shown to be a function of the precise selected resistance
mechanism, gene(s) or allelic substitution. Within these favourable conditions
for resistance selection (RB > RC), there will be fitness combinations
for the R and S genotypes that will maximize the selection intensity (SI) and subsequent rate of herbicide
resistance evolution. Estimation of fitness of a herbicide
resistant (R) genotype under herbicide
selection (WR(h)) is usually
expressed as relative to the fitness in the herbicide free environment (WR). This
involves the quantification of resistance
decay (RD), a useful parameter
for ranking the
efficiency (i.e. weak vs. strong) of resistance alleles to protect the plant
from damage exerted by a particular herbicide and dose. Resistance benefit (RB), cost (RC) and decay (RD) are different aspects of plant
fitness all required for a proper estimation of selection intensity (SI)
and dynamics of herbicide resistance alleles in agroecosystems.