salt and water stress of accase herbicides resistant and susceptible populations of rigid ryegrass (lolium rigidum)

Laboratory studies were conducted to compare the relative fitness of clodinafoppropargyl herbicide resistant lolium rigidum accessions with their clodinafoppropargyl susceptible counterparts in 2014. factors evaluated were lolium populations at constant salinity stress (0, 5, 10, 15, 20 and 25 ds cm2) and water stress (0, 3, 6, 9, 12 and 15 bar). the maximum germination in salinity stress was among three biotypes regarding susceptible biotype with 93.62 percent. the concentration of salinity which 50% seeds germination reached s and semir biotypes to the is more than rbiotype. in salinity stress the highest rate of germination in the s biotype of 8.66 (number of germinated seeds in days) at a concentration of 17 ds rg reaches 50% in s and semir biotypes and in r biotypes in salinity 14 ds cm2. the results of the application of various potential water showed that the more negative water potential, germination all biotypes (r, semir and s) dropped and in potential 15 bar pg in r and semir biotypes to less than 15 percent. coefficients from the regression equation sigmoid three parameter data pg resistant and susceptible biotypes showed that semir biotype compared to r and s were more tolerant of water stress and in water potential 7.5, it pg reduced to 50 percent. in examining the relative fitness of ryegrass biotypes water and salinity stress showed that semir and r biotypes the cost of considerable fitness, but the most results cost fitness no significant.