Allelopathic activities of selected Mucuna pruriens on the germination and initial growth of lettuce

The study was conducted to test allelopathic effects of some Mucuna pruriens on the germination and growth of lettuce. The effects of root exudates and leaf leachates of eight mucuna genotypes; Mucuna pruriens var. utilis cv. cinza , Mucuna pruriens var. utilis cv. preta , Mucuna pruriens var. utilis cv. hassjo , Mucuna pruriens var. utilis cv. fvb , Mucuna pruriens 82/507, Mucuna pruriens 82/508, Mucuna pruriens 82/116, and Mucuna pruriens GA/94/002 were tested on the germination, radicle, and hypocotyl elongations of lettuce ( Lactuca sativa var. Great Lakes 366). The effects of leaf leachates and root exudates of mucuna were tested using sandwich and plant-box methods respectively with lettuce as the receptor plant. Roots exudates inhibition varied significantly among genotypes (94.3%-98.5%). Root exudates of Mucuna pruriens var. utilis cv. fvb had the maximum inhibition (98.5%). Lettuce radicle inhibition gradually decreased with distance from the mucuna plant in a plant-box and with high correlation (r=0.910-0.952; p<0.05) between lettuce radicle inhibition and distance from mucuna roots. The effect of 50 mg oven-dried mucuna leaves had significant inhibition on lettuce radicle elongation (12.0%-15.8% of untreated control). Leaf leachates had less effect on the hypocotyl elongation of lettuce (50.5%-72.0% of untreated control) at the same application of oven-dried leaves (50 mg/10 ml agar).