Differences in Germination, Growth, and Fecundity Characteristics of Dicamba-Fluroxypyr-Resistant and Susceptible Kochia scoparia

The widespread occurrence of herbicide-resistant (HR) Kochia scoparia is an increasing concern for growers in the US Great Plains and Canada. K. scoparia populations resistant to dicamba have been reported in six US states. Populations cross-resistant to dicamba and fluroxypyr have been reported fro...

Full description

Saved in:
Bibliographic Details
Published inPloS one Vol. 11; no. 8; p. e0161533
Main Authors Kumar, Vipan, Jha, Prashant
Format Journal Article
LanguageEnglish
Published United States Public Library of Science 18.08.2016
Public Library of Science (PLoS)
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary:The widespread occurrence of herbicide-resistant (HR) Kochia scoparia is an increasing concern for growers in the US Great Plains and Canada. K. scoparia populations resistant to dicamba have been reported in six US states. Populations cross-resistant to dicamba and fluroxypyr have been reported from wheat fields in Montana, USA. It is unclear whether resistance to the auxinic herbicides (dicamba and/or fluroxypyr), can alter the fitness traits of K. scoparia. The objectives of this research were to compare the germination dynamics in response to thermal environment, vegetative growth and fecundity characteristics, and the relative competitive ability of dicamba-fluroxypyr-susceptible (S) vs.-resistant (R) K. scoparia selected from within a single segregating population (collected from wheat-fallow field in MT). S and R selected lines were developed after three generations of recurrent group selection. Compared to the S selected line, the R selected line had lower cumulative germination at all constant temperatures except 25°C, and at all alternating temperatures except 30/35°C. Also, the R selected line had delayed germination relative to the S selected line. The R had lower plant height, plant width, primary branches, total leaf area, stem diameter, and shoot dry weight compared with the S plants in the absence of competition. The reduction in seed production per plant resulted in a 39% fitness cost. The 1000-seed weight of R (1.6 g) was also less than that of S (2.6 g). When grown in an intraspecific competition at different mixture proportions, replacement series indices for the growth parameters further indicated that the R was less competitive than the S. Evident from this research, the dicamba-fluroxypyr-resistant R selected line is less likely to persist in a field population in the absence of the auxinic herbicides.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
Conceptualization: PJ VK. Data curation: VK PJ. Formal analysis: VK PJ. Funding acquisition: PJ. Investigation: VK. Methodology: VK PJ. Project administration: PJ. Resources: PJ. Software: VK. Supervision: PJ. Validation: PJ. Visualization: VK PJ. Writing - original draft: VK. Writing - review & editing: PJ.
Competing Interests: The authors have declared that no competing interests exist.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0161533