Biomass, Fecundity, and Interference Ability of Multiple Herbicide-Resistant and -Susceptible Late Watergrass (Echinochloa phyllopogon)

• Published in: Weed science Vol. 60; no. 3; pp. 401 - 410
• Main Authors: Boddy, Louis G., Streibig, Jens C., Yamasue, Yuji, Fischer, Albert J.
• Format: Journal Article
• Language: English
• Published: 810 East 10th Street, Lawrence, KS 66044-8897 Weed Science Society of America 01.07.2012; Cambridge University Press
• Subjects: Biological and medical sciences; Chemical control; Competition; Confidence intervals; Crop harvesting; Echinochloa; Ecological competition; Experiments; Fecundity; fitness; Fundamental and applied biological sciences. Psychology; Herbicide resistance; Herbicides; Niche differentiation; Nondestructive testing; Oryza sativa; Parasitic plants. Weeds; Phytopathology. Animal pests. Plant and forest protection; Plant roots; Plants; reciprocal yield models; Rice; root interference; Seed banks; Seeds; WEED BIOLOGY AND ECOLOGY; Weeds; United States > US; California; USA, California; Competition; root interference; niche differentiation; synonyms: E. oryzicola (Vasinger) Vasinger., E. crus-galli (L.) P. Beauv. var. phyllopogon (Vasing.) Ohwi, rice (Oryza sativa L.); fitness; Late watergrass, Echinochloa phyllopogon (Stapf.) Koss., ECHPH; herbicide resistance; reciprocal yield models; Ability; Monocotyledones; Multiple; Weed; Pesticides; Interference; Biomass; Modeling; Herbicide; Sensitivity resistance; Gramineae; Weed science; Angiospermae; Spermatophyta; Yield; Pesticide resistance; Differentiation; Fecundity
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1614/WS-D-11-00150.1

Echinochloa phyllopogon is a serious weed of California rice that has evolved resistance to most grass herbicides. We assessed differences in growth, interference, and fecundity between multiple resistant (R) and susceptible (S) E. phyllopogon. Interference with rice by R and S plants was similar, although R plants were shorter and had less leaf area and shoot biomass than S plants. Interference by one S or R E. phyllopogon plant with rice was 2.31 or 2.45 times greater than intraspecific interference by one rice plant, respectively. Interference was mostly driven by root interactions and E. phyllopogon on average produced seven times more root dry weight than rice. Deeper E. phyllopogon root placement compared with rice may explain niche differentiation between the two species. On average, R plants produced 55% less seeds than S plants. Lower fecundity could compromise fitness of R plants in the absence of herbicide selection, but partial avoidance of seed removal during rice harvest through earlier seed shattering may allow greater soil seed bank replenishment by R plants compared with S plants. E. phyllopogon control is needed to prevent high rice yield losses, and suppressing survivors of initial herbicide treatments is essential to limit seed bank replenishment by R plants. The potential benefits of taller rice varieties with enhanced root competitiveness, and that may be harvested earlier, should be considered.