Registration of ‘Ocoee’ Root-Knot Nematode Resistant White Clover

Abstract

‘Ocoee’ (Reg. No. CV-32, PI 658492) white clover (Trifolium repens L.) is an intermediate-type white clover synthetic cultivar selected for root-knot nematode (Meloidogyne spp.; RKN) resistance. Susceptibility to RKN has been identified as a factor contributing to stand decline of white clover in the southeastern United States and other areas of the world. The objective of this breeding program was to select for RKN resistance in white clover starting with a base population of ‘Osceola’. Approximately 1200 plants of Osceola were initially screened for resistance to the southern RKN (M. incognita). Between 100 and 150 superior plants were selected and allowed to interpollinate. Five such cycles were conducted with 100 to 200 plants selected in each cycle. Upon completion of five cycles, the resulting population was designated UFWC5 and was evaluated for response to six different RKN populations and for plant performance under field conditions. UFWC5 was released as the cultivar Ocoee by the Florida Agricultural Experiment Station in 2006. At three locations in Florida, there were no differences in total seasonal dry matter yields of Ocoee compared with Osceola. In greenhouse RKN response experiments, Ocoee had lower root galling and egg mass production scores than Osceola. Spring dormancy response indicated Ocoee to be earlier than Osceola.