Investigation of the relative fitness and molecular base of resistant and susceptible rigid ryegrass (Lolium rigidum) biotypes to Acetyl Co-A- carboxylase herbicides

Sabet Zangeneh, Hossein (2018) Investigation of the relative fitness and molecular base of resistant and susceptible rigid ryegrass (Lolium rigidum) biotypes to Acetyl Co-A- carboxylase herbicides. Doctoral thesis, University of Mohaghegh Ardabili.

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Text (ارزیابی شایستگی نسبی و مبنای مولکولی توده‌های حساس و مقاوم چچم یک‌ساله (Lolium rigidum) به علف‌کش‌های بازدارنده‌ استیل کو آنزیم آ کربوکسیلاز) Hossein Sabet Zangeneh.pdf Download (414kB) | Preview

Abstract

To evaluate herbicide resistance, the molecular basis of resistance and fitness of rigid ryegrass (Lolium rigidum) biotypes collected from wheat fields across Khuzestan province ACCase-inhibiting herbicides, a study using the whole plant and petri dish bioassay and molecular during the years 2013 to 2016 in Ramin University and Research Centre, Agriculture and natural resources education Khuzestan province. In particular, 120 wheat fields were visited and 30 rigid ryegrass seed samples were collected for testing. Screening of these biotypes conducted with clodinafop-propargyl and pinoxaden under controlled greenhouse and petri dish conditions, resulted in 15 biotypes with a survival higher than 20% to this herbicide, which were further studied for the evaluation of cross-resistance, In the following some important information managerial fields is collected, and were analyzed. The next step is to determine the potential mechanism of resistance based on the location of CAPS and dCAPS methods were used. Cross-resistance of the masses, by examining their reactions to different chemical herbicides inhibiting ACCase pot method was evaluated by measuring the number of the living plants. In another experiment the effectiveness of herbicides with different mode of action for control of susceptible and resistant biotype to the herbicide clodinafop-propargyl was conducted. In the end, whether or not the fitness cost in three biotypes (two-resistant and susceptible biotypes) were evaluated. In experiment fitness an evaluation of germination and seedling emergence characteristics of three rigid ryegrass biotypes (one susceptible and two resistant biotypes) and of competition between this weed and wheat using replacement series experiments was conducted. The results showed that fresh weight percentage and the percentage of plant survival compared to control populations is the best traits for evaluating biotypes in terms of resistance and intensity of the effect herbicides. Of 13 rigid ryegrass biotypes that demonstrated cross-resistance to ACCase inhibitors, in 10 biotypes this was due to molecular mutation. In particular, it was revealed that resistance for one, eight and one of the molecular mutations could be attributed to a mutation in location 1781, 2041 and 1781 + 2041, respectively. On the contrary, there were no mutations in either location 2078 and 2088. Cross-resistance was observed in that the studied biotypes are different resistance models to ACCase- inhibiting herbicides three families. Evaluate the efficiency of different herbicides showed that the herbicides sethoxydim, clethodim, isoproturon+ diflufenican, paraquat and glyphosate were well controlled rigid ryegrass susceptible and resistant biotypes. The results relative merits conditions competitive and non-competitive ryegrass populations also showed that competitive conditions between resistant and susceptible populations differ in some traits seen that in some traits differences no significant but it seems susceptible biotype in conditions salinity and drought stress and in terms of competition in vegetative and reproductive stages as well as a stronger competitor than two resistant biotypes. In the province, 75% of fields used herbicides with different mode of action (rotation) were observed, but in 84% of studied fields, crop rotation that is the most important recommendation for the management of herbicide resistant weed population is not observed. Overall, it seems that despite the good recommendations regarding management of herbicide resistance in wheat fields, the farmers did not paid much attention to it. According to the results, the first cross-resistance to herbicides inhibiting ACCase Ryegrass was registered in Iran.

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