Determination of Pesticide Residues in Pulses Seed and Evaluation of their Phytotoxicity in Term of Germination and Early Seedling Growth by Hydroponic Culture

Residue of 37 pesticides was analyzed in pulse seeds (chick pea brown, green gram, black gram and soya bean) and effect of pesticide residues on germination and early seedling growth was evaluated to know the residual phytotoxicity. Out of 37 analyzed pesticides only five pesticides (?-HCH, malathion, chlorpyriphos, ethion, ?-cypermethrin) were detected in pulse seeds, in which chlorpyriphos and cypermethrin were frequently encountered in 39 % of total analyze (120) samples. Mean lowest residual level of chlorpyriphos and cypermethrin found in analysis was taken as lower treatment concentration (0.3 mg L-1), middle (3.0 mg L-1) and higher (30.0 mg L-1) with three exposure regimes continuous exposure during germination, short-term initial exposure of 4h and exposure after pre-germination. Phytotoxicity of pesticides treatments were evaluated by % shoot, root elongation and germination index. Finding of the study suggested that increase in concentration and exposure regimes reduced the % shoot, root elongation and germination index. Higher concentration and exposure regimes increase the residual load of pesticides which may be attributed to this effect. Continuous exposure of chlorpyriphos and cypermethrin at middle (3.0 mg L-1) and higher (30.0 mg L-1) concentration of treatment adversely affect the germination and early seedling growth of pulse seeds. Treatment of pre-germinated pulse seeds only show adverse effect on higher concentration treatment. Variation of reduction in germination and early seedling growth was reported because of pesticides uptake and sensitivity to pesticides treatment differs among the pulse seeds. Soyabean was found to be most sensitive to treatment of these pesticides. In green gram residual uptake was nearly same as in soyabean and greater than black gram, chick pea brown but reduction in germination and early seedling growth reasonably less to other pulse seeds due their less sensitivity to these treatments. Lower treatment concentration of pesticides with all exposure regimes does not affect the germination and early seedling growth.