Pyridate is the only selective herbicide of chickpea. It is necessary to use it in chickpea fields to control broad leaf weeds The high price of the herbicide will increase the cost of crop production. Paraquat is a general, contact and inexpensive herbicide. Therefore, the possibility of pyridate substitution by Paraquat was evaluated through dose-response test.this study was conducted as factorial based on completely randomized design with four replications in research greenhouse of the Faculty of Agriculture, University of Kurdistan in February 2017. Factors included four chickpea cultivars (Arman, Samin, ILC482 and Hashem) and Paraquat doses (0, 18.75, 37.5 75 and 100% of recommended dose). Plant height and regrowth dry matter of shoots 21 days after spraying was measured. A four parameters logistic equation fitted to data in order to investigation of regrowth dry matter and plant height trend against Paraquat dose. Results showed that
Effective dose of Samin, Arman, ILC482 and Hashem cultivars for 50% dry matter reduction was 25.33, 23.02, 19.81 and for plant height reduction was 31.05, 22.79, 29.62 and 25.62 of recommended dose respectively. The height of Hashem cultivar decreased by 100%, 60.41%, compared to the control, while in the 100% dose, Samin 49/79, Arman 56.09 and ILC 482 74.56%, respectively, were higher than their height They had less. Samin cultivar began to grow again after 5 days after poisoning. The highest damage was observed among the cultivars tested in Hashem cultivar. The higher effective dose can indicate the higher tolerance of a cultivar to a herbicide. Therefore, it can be concluded that Samin, Arman, ILC 482 and Hashem are more tolerant to paraquat respectively.