Competition between ACCase-Inhibitor Resistant and Susceptible Sterile Wild Oat (Avena sterilis) Biotypes

Abstract

Studies were conducted to determine the growth, fecundity, and competitive ability of an acetyl-CoA carboxylase (ACCase)–inhibitor resistant (R) sterile wild oat biotype compared with a susceptible (S) biotype. Seed germination studies indicated that there were no differences in seed germination and seedling vigor between R and S biotypes at any temperature regime. R and S biotypes were grown under noncompetitive and competitive arrangement in the greenhouse. Under noncompetitive greenhouse conditions, growth of the R biotype was similar to that of the S biotype on the basis of plant height, canopy area, and plant biomass. Seed production and weight of R and S plants were also at the same levels. Furthermore, relative competitiveness among the R and S sterile wild oat biotypes was investigated by means of replacement series experiments. The R and S biotypes were compared under seven mixture proportions (6 : 0, 5 : 1, 4 : 2, 3 : 3, 2 : 4, 1 : 5, and 0 : 6). No significant differences in competitive ability were observed between R and S biotypes on the basis of plant height, canopy area, or plant biomass. In most cases, relative crowding coefficient (RCC) values at 20, 60, and 100 d after transplanting (DAT) were close to one, indicating equal competitiveness between the R and S biotypes of wild oat used in this competitive study. However, in some cases, the RCC value was 1.31 for plant height, evident of a slight competitive advantage for the R biotype at 100 DAT. In general, ACCase-inhibitor R and S sterile wild oat biotypes were equally competitive, clearly without any growth penalty for R plants in either noncompetitive or competitive conditions.

First Case of Glufosinate-Resistant Rigid Ryegrass (Lolium rigidum Gaud.) in Greece

“…It has to be noted that the resistant accession was found in the area near susceptible accessions. Such an observation is in agreement with the findings of previous studies for other weed species [21,26]. Even if the field history was not known for all sites, conversation with growers from the orchards and vineyards with the resistance issues provided history of continuous glufosinate use at twoto fourtimes higher than the labeled rate.…”

Study of Fitness Cost in Three Rigid Ryegrass Populations Susceptible and Resistant to Acetyl-CoA Carboxylase Inhibiting Herbicides

“…Previous studies on several weeds have shown either higher seed production for R compared with the S population (Purrington and Bergelson, 1997;Park et al, 2004), or no differences at all between the several biotypes (Alcocer-Ruthling et al, 1992; Thompson et al, 1994;Travlos, 2013).…”

“…Some resistant biotypes of rigid ryegrass were also shown to be more competitive in terms of seed size compared to the susceptible population (Pedersen et al, 2007). Travlos (2013) showed that there were not any significant fitness differences between ACCase-inhibitor FIGURE 1 | Star (*) and R rating system to distinguish the degree of resistance, according to the response to a single dose of herbicide in resistance screening (Moss et al, 1999). The numbers in parentheses represent the standard errors of the means.…”

Detection of Acetyl-CoA Carboxylase (ACCase) Inhibitor Herbicides Resistance in Sterile Wild Oat (Avena sterilis L.) Using Agar Quick Test

“…It possess an important economic menace to crop yields, because of their high spread germination and great degree of phenotypic differentiation, essential generative produce and in the absence of competition, A. sterilis being considered to produce large number of seeds, and ability of seed to remain in the soil seed bank [1][2][3]. Sterile wild oat has been found in Mediterranean climate zone, such as Southern Europe and Northern Africa [4].…”