Shepherd’s purse (
Capsella bursa-pastoris [L.] Medik.)
is a troublesome dicot weed that occurs in major wheat
(
Triticum aestivum
L.) production areas in China.
Tribenuron-methyl failed to control shepherd’s purse
in some fields in Runan County, Henan Province. This
study aimed to establish the cross-resistance pattern of a
resistant (R) population and explore the potential targetsite
and non-target-site based resistance mechanisms.
Acetohydroxyacid synthase (
AHAS) gene sequencing
revealed a single nucleotide change of CCT to CGT
resulting in the Pro to Arg substitution at amino acid
position 197 in resistant individuals. Compared with the
susceptible (S) population, R population displayed high
level resistance to tribenuron-methyl. Cross resistance
patterns showed that the R population was high resistant
to flucarbazone-Na; moderately resistant to florasulam;
low resistant to pyrithiobac sodium and pyroxsulam,
and sensitive to imazethapyr. The pretreatment of
malathion reduced the 50% growth reduction (GR
50)
value of tribenuron-methyl by 29% in the R population,
suggesting that target-site resistance and non-target-site
resistance mechanisms were both present in tribenuronmethyl
-resistance of shepherd’s purse. This is the first
report of the acetolactate synthase Pro197Arg mutation in
shepherd’s purse.
