مقاومت عرضي منفي در توده هاي علف هرز دُرنه (Echinochloa colona (L.) Link) مقاوم به آترازين در مزارع نيشكر (L. Saccharum officinarum)

Negative cross resistance in atrazine resistant junglerice (Echinochloa colona (L.) Link) populations in sugarcane (Saccharum officinarum L.) fields

مقاومت عرضي منفي بر اثر بروز مقاومت به تريازين ها در چندين مورد از بايوتايپ هاي مقاوم گزارش شده است؛ به طوري كه اين پديده منجر به بروز حساسيت زياد در اين بايوتايپ ها نسبت به علف كش هاي فنيل اوره و ساير بازدارنده هاي فتوسنتز در فتوسيستم ۲ مي شود. بدين منظور، مقاومت عرضي منفي در توده هاي مقاوم به علف كش هاي خانواده تريازين علف هرز دُرنه در مزارع نيشكر كشت و صنعت كارون شوشتر پژوهشي در طي سال هاي ۹۴-۱۳۹۳ با استفاده از آزمايش هاي گلداني در دانشگاه كشاورزي و منابع طبيعي رامين خوزستان مورد بررسي قرار گرفت. نتايج آزمايش غربال اوليه براساس شاخص هاي اندازه گيري شده نشان داد سه توده به علف كش آترازين مقاوم بودند. همچنين، نتايج بدست آمده از آزمايش دز - پاسخ بر مبناي شاخص مقاومت توده ها نشان داد كه توده هاي R۱، R۲ و R۳ به ترتيب با درجاتي بين تا ۱۲/۲۶، ۶/۵۹ و ۳/۷۵ بر مبناي وزن تر و ۵/۳۷، ۴/۲۲ و ۴/۷۱ تعداد گياهان زنده مانده به علف كش آترازين مقاوم بودند. نتايج حاصل از اين پژوهش مقاومت عرضي منفي توده هاي دُرنه مقاوم به علف كش آترازين را نسبت به علف كش هاي تبوتيورون، لينورون، دايورون و دايورون+ هگزازينون را در محدوده بين ۰/۵۶ تا ۱/۶۲ بر مبناي وزن تر و بين ۰/۵۲ تا ۳/۲۶ بر مبناي تعداد گياهان زنده مانده نشان داد. همچنين، توده هاي مقاوم بيشترين مقاومت عرضي منفي (حساسيت) را نسبت به علف كش دايورون + هگزازينون نشان دادند.

Introduction: In negative cross-resistance, herbicide-resistant plants being more sensitive to herbicides than susceptible plants. Negative cross-resistance to other herbicides have been found in triazine-resistant biotypes of weeds. These biotypes are more sensitive to phenyl urea group of herbicides, as well other herbicides of triazine group. Also, negative cross-resistance has been reported to bentazone for Brassica napus L, and Amaranthus retrojlexus L, and to pyridate for B. napus, and Epilobium ci/iatum Raf.. Furthermore, positive cross-resistance to bentazone has been found in Chenopodium album L., and Solanum nigrum L.. The goal of this study was to search for herbicides that exert negative cross-resistance at the whole-plant level in order to control atrazineresistant populations ofjunglerice in sugarcane fields. Materials and Methods: Suspected resistant and susceptible seeds of junglerice to atrazine were collected from sugarcane fields and adjacent areas to Karun Agro-lndustry Inc., Shushtar, southwestern of Iran at 2014 - 2015 growing season. These populations were named according to their status and abbreviated as follows: Rl, R2, R3 and S (susceptible population). All collected seeds (R-and S-populations) were stored at room condition (25 'C). Herbicides used in this study were tebuthiuron (0, 10, 20, 100, 200, 1000, 2000, 10000 ml ai ha· 1), linuron (0, 10, I 00, 160, 1000, 1600, I 0000 ml ai ha·' ), diuron (0, I 0, 30, 100, 360, 1000, 3600, I 0000 g ai ha·') and diuron + hexazinone (0, 10, 24, 100, 240, 1000, 2400, 10000 g ai ha· 1). For the pre-emergence application treatment, 10 seeds were sown in 500-ml plastic pots containing clay:sand mix. Then, herbicides were applied using a back pack sprayer with flood nozzle calibrated to deliver 350 lit ha·' to the suspected resistant and susceptible junglerice populations on one day after sowing. Plants were thinned to four plants per pot. The aboveground biomass was harvested on 28 days after treatment, dried at 75 'C for 48 h, and weighed. Data were expressed as a percentage of the untreated control. The experiment was a completely randomized block design with fQur replications and was repeated. The data were analyzed using nonlinear regression model in R software (drc packege). Three or four parameters log-logistic equation was fitted to the observed data to describe the response of populations to herbicides; susceptible population was considered as an index in order to compare the resistance levels of the populations. Results and Discussion: The result of screening test showed that three populations were resistant to atrazine. The results of dose-response analyse for atrazine revealed that resistance factor (RF) for R I, R2 and R3 populations were 12.26, 6.59 and 3.75 based on fresh weight(% of control) and 5.37, 4.22 and 4.71 based on number of survival plants (% of control), respectively. ED so values of R I, R2 and R3 populations were 36.85, 73.01 and 41.71 ml ai ha· 1 oftebuthiuron compared with 44.42 ml ai ha·' inS-population. RF values in the Rl, R2 and R3 populations were 0.80, 1.53 and 0.72 oftebuthiuron, respectively. EDso values of the Rl, R2 and R3 populations were 92.76, 107.73 and 106.84 ml ai ha·' of linuron compared with 152.51 ml ai ha·'in S-population. RF values of the Rl, R2 and R3 populations were I, 1.89 and 3.26 oftebuthiuron, respectively. EDso values of the Rl, R2 and R3 populations were 74.21, 95.25 and 69.80 g ai ha· 1 ofdiuron compared with 79.03 g ai ha·' in S-population. l11e RF of the R I, R2 and R3 populations were 0.97, 0.85 and 1.18 of diuron, respectively. The ED50 values of the Rl, R2 and R3 populations were 62.11, 49.48 and 54.30 g ai ha·' of diuron+hexazinone compared with 88.72 g ai ha·' inS-population. RF values of the Rl, R2 and R3 populations were 0.62, 0.68 and 0.52 for diuron+hexazinone, respectively. The results showed negative cross resistance to tebuthiuron, linuron, diuron and diuron + hexazinone in the resistant populations. Conclusions: In present study, the R2 population was the most sensitive to diuron+hexazinone in comparison to other populations (RF ~ 0.56).The resistance of other populations treated with this herbicide was lower than other herbicides. Therefore, this mixture can alone control a wide range of weeds and is more reliable than herbicides that are used alone. Mixing herbicides both economically and environmentally, will reduce cost less than each time they are applied individually. Therefore, this mixture is recommended for controlling atrazine resistant weeds in sugarcane fields. Negative cross resistance may be the major reason that resistance to atrazine do not evolve where herbicide mixtures were used, when the mixed herbicide (usually a non-PS II inhibiting acetanilide) also controlled triazine-sensitive weeds.