Physical and Cultural Weed Control Working Group of - European ...

9 th EWRS Workshop on Physical and Cultural Weed Control 57
Samsun, Turkey, 28 – 30 March 2011
Chlorsulfuron and trifensulfuron-methyl (herbicides)-resistant Sinapis arvensis
L. biotypes show vigorous germination potential
M. Topuz 1 , Y. Nemli 2 and A. K. Mattoo 3*
1 Plant Protection Research Institute, Bornova, Izmir, Turkey
2 Department of Plant Protection, Ege University, Izmir, Turkey
3 Sustainable Agricultural Systems Laboratory, USDA-ARS, Henry A.Wallace Beltsville
Agricultural Research Center, Beltsville, MD 20705-2350, USA
Our studies have identified and confirmed at biochemical and molecular levels the presence of
chlorsulfuron-resistant biotypes of the weed S. arvensis in wheat fields of Turkey. Here, we present
evidence that freshly harvested and after-ripened wild mustard (Sinapis arvensis) seeds from
chlorsulfuron resistant and susceptible biotypes exhibit different patterns of germinability under the
tested conditions.
Experiments were carried out under controlled (laboratory, environmental chamber and
greenhouse) conditions to compare seed germination patterns and emergence differences of
chlorsulfuron resistant (R) and susceptible (S) S. arvensis biotypes. Seed germination was tested at
different temperature regimes (5º,.10º,.15º and 22ºC) and after extended periods of dry-storage
(after-ripening) (4 months, 2 years and 4 years).
Results of the study showed that S.arvensis seeds from two resistant biotypes had higher
germination rates, 74.0-81.9%, compared to two susceptible biotypes, 24.3-27.1%. Except at 5ºC,
where no germination occurred, similar germination patterns were obtained at 10º,15º and 22ºC
under laboratory, greenhouse and environmental chamber growth-conditions. Total cumulative seed
germination percentage of ‘R’ biotypes was significantly higher than that of the ‘S’ biotypes.
Moreover, seeds of R biotypes germinated 72 hours sooner than the S biotypes. However, the
maximum cumulative germination was found to be a function of dry storage (after-ripening).period.
Freshly harvested 4-months dry-stored seeds of ‘S’ biotypes had higher initial germination, which
considerably decreased with storage time of 2 and 4 years. The seeds from ‘R’ S. arvensis biotypes
showed an opposite trend: low initial germination (12%) in seeds stored for 4 months compared to
68% germination of seeds stored for 4 years.
These data suggest that chlorsulfuron-resistant S.arvensis biotypes, with the ability to
germinate fast and at a higher percentage, and the advantage to sustain their germinability even after
a long storage time of 4 years, have the capacity to be more competitive than the susceptible
counterparts. The impact of these observations on developing new weed management strategies will
be discussed.