Molecular markers indicate intraspecific variation in the control ofEchinochloaspp. with quinclorac

Abstract

Some species of the genusEchinochloaare troublesome weeds in rice fields. The taxonomy of this genus leads to confusion in many cases due to its great morphological diversity. Because of the differential sensitivity to the herbicide quinclorac shown byEchinochloaspp., it was necessary to assess the botanical and molecular characterization of this weed.Echinochloa colonum, E. oryzoides, andE. oryzicolawere very susceptible to quinclorac treatment; by contrast,E. crus-galliandE. hispidulashowed some degree of natural tolerance. Physiological and molecular results agreed with the botanical classification of the genusEchinochloain Flora Europea. The importance of these results is due to yield losses produced by the infestation ofEchinochloaand the need for a strategy forEchinochloamanagement depending on the distribution of theEchinochloaspecies.

Interference interactions of two rice cultivars and their F3cross with barnyardgrass (Echinochloa crus-galli) in a replacement series study

“…The weed is a very aggressive invader, difficult to control, and causes major losses in rice production (Lopez-Martinez et al 1999). VanDevender et al (1997) reported that 20 BYG m Ϫ2 can reduce rice yield by 80%.…”

“…In recent years, quinclorac has been used to control BYG, but some of these populations also have developed increased tolerance to quinclorac (Lopez-Martinez et al 1999). The development of these herbicide-resistance populations has led to increased interest in alternative methods to control BYG (Gealy et al 2003).…”

Genetic and morphologic diversity of Echinochloa crus-galli populations from different origins

“…Although high values of genetic variation are sometimes reported, this appears to be typical of plants that reproduce mainly by seed (Asins et al 1999;Lopez-Martinez et al 1999;Roy et al 2000;Rutledge et al 2000). For genetic polymorphism, seven primers produced a total of 55 RAPD bands, about 85.1% of which were polymorphic among the 34 populations of E. crus-galli.…”

“…E. crus-galli found in rice production exhibits significant differences in morphology and genes, which may be related to different sensitivity to herbicides. Because of this high variability, morphological characters and physiological response to herbicides in different taxonomic classifications have been proposed by several authors who found different results by using morphological, isozyme or molecular markers (Asins et al 1999;Lopez-Martinez et al 1999;Rutledge et al 2000).…”

Effects of surfactants on primisulfuron activity in barnyardgrass (Echinochloa crus‐galli [L.] Beauv.) and green foxtail (Setaria viridis [L.] Beauv.)

“…1977). This weed is a very aggressive invader, difficult to control, and causes major losses in rice production (Lopez‐Martinez et al . 1999).…”