Glyphosate Resistance in Kochia

(Female) My name is Mithila Jugulam. I am a Weed Physiologist in the
Agronomy Department at Kansas State University. I received funding from
Kansas Soybean Commission last year to work on a project on genetic basis
of glyphosate resistance in Kochia, so with the last year funding, I was
able to hire a graduate student and starting off they worked on glyphosate
resistant Kochia. As most of us know, herbicide resistant weeds will pose
serious threat to sustainable agriculture, including Kansas. So we have
glyphosate resistance in Kochia documented in 2007. Since then, the
infestation of glyphosate resistant Kochia across Kansas has increased
extensively. My main aim in this research is to determine the inheritance
of glyphosate resistance in this weed. By that, we can understand the
evolution of resistance to herbicides in weeds and specifically in this
case, glyphosate resistance in Kochia and also by understanding the genetic
basis, we can also determine possible spread of this resistance across
geographies in Kansas and also across the U.S. Basically we double upped a
fund for first filial generation of a progeny and looked at the resistance
to glyphosate in this plant. In addition to that, earlier reports suggested
that glyphosate resistance in Kochia is due to increasing EPSDS gene copy
number. EPSDS is an enzyme that is the target sight for glyphosate in
plants, so in resistant plants, the enzyme is produced in excess copies so
that even if we apply in normal field recommended dose of glyphosate and
resistant plant can withstand the glyphosate application, therefore can
survive and reproduce, so since we know that resistant plants produce up to
nine copies, we looked in the F1 plants, how many copies are presented and
what is the level of resistance. So far when we tested several different F1
plants, we found that the F1 progeny consisted of an intermediate number of
copies of EPSDS gene, in other words, if we had up to ten copies for
resistant plants, whereas in F1 plants, we had anywhere from three to
seven copies of this gene. However, having three or one copies of this gene
is sufficient for the plant to withstand a field application dose of
glyphosate, therefore they have resistance in F1 progeny, so in the next
year what we are interested to do is if I get successful in getting funds I
gained from Kansas Soybean Commission, we are interested to look at the
segregation of resistant susceptible plants in next generation, that is F2
generation, and determine how many genes are controlling glyphosate
resistance in Kochia.

 

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