TITLE:
Conyza sumatrensis Intrapopulation Variation in Response to Glufosinate
AUTHORS:
Ivana Paula Ferraz Santos de Brito, Caio Antonio Carbonari, Bruna Barboza Marchesi, Ana Karollyna Alves de Matos, Leandro Tropaldi, Nilda Roma-Burgos, Edivaldo Domingues Velini
KEYWORDS:
Ammonia Accumulation, Differential Tolerance, Glutamine Synthetase, Herbicide Selection Pressure, Sumatran Fleabane
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.10 No.9,
September
17,
2019
ABSTRACT: We aimed to study the response of Conyza
sumatrensis to different doses of glufosinate, intrapopulation variation in
sensitivity to the herbicide, and the heritability of phenotypic response, and
model the evolution of resistance. Three studies were conducted in the
greenhouse with two repetitions. First, we tested doses of glufosinate (0, 50,
100, 200, 400, 800 g a.i. ha-1) plus a nontreated check, with four replications. Second,
we examined the range in sensitivity of 44 plants to 200 g a.i. ha-1 glufosinate. Third, we evaluated the sensitivity of the progeny of six
glufosinate-treated plants to 200 g a.i. ha-1 glufosinate. Plant response was
evaluated visually and the ammonium content in leaf tissues was measured.
Glufosinate at 400 g a.i. ha-1 caused the highest injury to C.sumatrensis plants.
Ammonia accumulation occurred in response to glufosinate treatment, regardless
of dose. Ammonia accumulation was correlated strongly with the level of visible
plant injury; thus, it is a good indicator of herbicide efficacy. Sensitivity
to glufosinate was highly variable within the population. Plants with high
ammonia concentration (high injury) after treatment with glufosinate produced
progenies that also had high ammonia concentrations after herbicide treatment.
The variation in ammonia accumulation among siblings was high. Simulating the
exclusion of plants that accumulated more ammonia produced a population that is
expected to be less sensitive to glufosinate in the next generation. The
stronger the selection pressures by a
simulated treatment with glufosinate, the greater the reduction in ammonia
accumulation in the progeny and expected sensitivity to glufosinate.