Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Ecological Fitness of Acetolactate Synthase Inhibitor-Resistant and -Susceptible Downy Brome (Bromus tectorum) Biotypes

Kee Woong Park, Carol A. Mallory-Smith, Daniel A. Ball and George W. Mueller-Warrant
Weed Science
Vol. 52, No. 5 (Sep. - Oct., 2004), pp. 768-773
Stable URL: http://www.jstor.org/stable/4046822
Page Count: 6
  • Read Online (Free)
  • Download ($29.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Ecological Fitness of Acetolactate Synthase Inhibitor-Resistant and -Susceptible Downy Brome (Bromus tectorum) Biotypes
Preview not available

Abstract

Studies were conducted to determine the relative fitness and competitive ability of an acetolactate synthase (ALS) inhibitor-resistant (R) downy brome biotype compared with a susceptible (S) biotype. In previous research, the mechanism of resistance was determined to be an altered ALS enzyme. Seed germination of the R biotype was compared with that of the S biotype at 5, 15, and 25 C. There were no different germination characteristics between R and S biotypes at 15 and 25 C. However, the R biotype germinated 27 h earlier than the S biotype and had reached over 60% germination when the S biotype initially germinated at 5 C. Under noncompetitive greenhouse conditions, growth of the R biotype was similar to that of the S biotype on the basis of shoot dry weight, leaf area, and plant height. Seed production of the R biotype was 83%, when compared with the S biotype, but seeds of the R biotype were larger than those of the S biotype. Replacement series experiments were conducted in the greenhouse to determine the relative competitive ability of R and S biotypes. No difference in competitive ability was observed between R and S biotypes on the basis of shoot dry weight, leaf area, or plant height. Thus, it appears that ALS-resistance trait is not associated with growth penalty in either noncompetitive or competitive conditions. In the absence of ALS inhibitors, these results suggest that the R biotype would remain at a similar frequency in a population of R and S biotypes.

Page Thumbnails

  • Thumbnail: Page 
768
    768
  • Thumbnail: Page 
769
    769
  • Thumbnail: Page 
770
    770
  • Thumbnail: Page 
771
    771
  • Thumbnail: Page 
772
    772
  • Thumbnail: Page 
773
    773