effect of trifluralin herbicide residues in soil on growth and nodulation of chickpea genotypes

in order to study the effect of trifluralin herbicide soil residues on growth and nodulation of chickpea genotypes, a greenhouse experiment was conducted at ferdowsi university of mashhad. a factorial experimental was conducted based on completely randomized design with three replications. treatments included of four genotyps of chickpea (hashem, ilc, kaka and kermanshahi) and seven concentration of trifluralin herbicide residue in soil (0, 6.4, 9.2, 18, 27.6, 36.8 and 55 µg.kg-1.soil). plants emergence percentage was determined 7 days after their emergence and at the beginning flowering stage, plants survival, height, number of lateral branches, shoot and root biomass, nodule number and nodule fresh weight were recorded. results showed, all measured traits were decreased significantly in all genotypes by increasing of trifluralin concentration in soil. at the lowest concentration (6.4 µg.kg-1.soil) of trifluralin in soil, chickpea shoot and root biomass were decreased 48.64 and 39.80 percent respectively and their lost reached to 97.96 and 96.39 percent respectively, when trifluralin concentration in soil was at the highest level (55 µg.kg-1.soil). among the studied genotypes of cheakpea, the highest of shoot (74.93%) and root (71.51%) biomass lost were observed in kaka genotype and the lowest shoot (64.72%) and root (55.96%) biomass lost were observed in the varieties of kermanshahi and hashem respectively. based on ed50 parameter, among the chickpea genotypes, ilc (3.23 µg.kg-1.soil) and kermanshah (8.22 µg.kg-1.soil) appeared to be the most susceptible and tolerant genotypes to trifluralin soil residue respectively. the other chickpea genotypes were classified by tolerant to trifluralin soil residual to: kermanshahi> hashem> kaka> ilc.