EFFECTS OF PYRIDATE ON CHICKPEA

The effects of pyridate on 15 different chickpea (Cicer arietinum L.) genotypes have been investigated under controlled environmental condit ions. Different degrees of tolerance to pyridate were detected. Pyrida te applied at 2.0 and 4.0 kg active ingredient ha(-1) inhibited the gr owth of two of the 15 genotypes. Chlorophyll fluorescence intensity sh owed high levels of inhibition 3 h after treatment in chickpea. For al l the genotypes, photosynthetic activity was recovered 10 days after t reatment. Fluorescence-induction curves revealed that pyridate inhibit ed photosynthetic electron transport in chickpea genotypes and Amarant hus blitoides faster than in Lolium rigidum. Photosynthesis in chickpe a genotypes recovered more quickly than in Lolium rigidum, while Amara nthus blitoides died 3 days after treatment. Hill reaction assays conc luded that CL9673 was the most phytotoxic pyridate metabolite. The ord er of phytotoxicity was CL9673 >> CL9673-N-Gly > CL9869 > pyridate > C L9673-O-Gly. These results support the idea that tolerance of chickpea to pyridate is due to degradation and detoxification of the herbicide .