Invasion and reproduction of Pratylenchus penetrans in birdsfoot trefoil cultivars

Greenhouse trials were conducted to determine the levels of invasion of bir dsfoot trefoil (Lotus corniculatus) cultivars and lines by the root-lesion nematode (Pratylenchus penetrans). Numbers of nematodes in roots grown in 5 0-cm(3) polystyrene starter pots were determined 6 weeks after planting. Ne matodes were detected in the roots of all cultivars and lines, though the d egree of invasion varied significantly. In the first screening trial, carri ed out in 1994 on 23 cultivars and lines, NB90-104, Upstart, and Viking har bored the lowest population densities of nematodes with levels below 1 000 g(-1) of dry root, while Fergus and EPF had population densities over 30 00 0 g(-1) of dry root. In the second screening trial conducted in 1995, all n ine cultivars and lines tested, including NB90-104, Upstart, and Viking, ha d nematode levels greater than 7 900 g(-1) of dry root. The results indicat ed that the cultivars and lines tested in this study exhibited wide genetic variability for invasion by root-lesion nematodes.