Allelopathic Effects of Sunflower on Succeeding Mungbean (vigna Radiata L. Wilczek) Crop

We studied the allelopathic effects of sunflower on the succeeding mungbean crop and also identified and quantified the allelochemicals present in different plant parts of sunflower using HPLC. Phenolic compounds present in leaves of sunflower were : Chlorogenic acid (18.53 +/- 0.66 mg/100 g) > trans-ferulic acid (17.96 +/- 1.15 mg/100 g) > caffeic acid (17.32 +/- 1.59 mg/100 g) > vanillic acid (15.34 +/- 1.07 mg/100 g), while stem contained trans-ferulic acid (17.92 +/- 1.57 mg/100 g) > chlorogenic acid (16.31 +/- 0.95 mg/100 g) > vanillic acid (15.15 +/- 0.91 mg/100 g) and root contains only trans-ferulic acid (13.6 +/- 1.2 mg/100 g). The seed yield of mungbean was significantly higher in fallow-mungbean rotation (716 kg/ha) than in sunflowermungbean sequence (593 kg/ha). Among the sowing periods, the crop sown on June 14 gave significantly higher seed yield (904 kg ha(-1)) than other sowing dates except June 21 (837 kg ha(-1) ). The seed yield of mungbean in fallow-mungbean rotation sown on June 14 was 1038 kg ha(-1) than sunflower-mungbean rotation sown on June 14 (770 kg ha(-1) ).