The CORESTA Bacterial Wilt Collaborative Sub-Group was set up in 1994 and the first trials were grown in the Southern hemisphere in the 1995/96 season. The mandate was to collect information on bacterial wilt (Ralstonia solanacearum (Smith) Yabuuchi et al.), in particular on the response of resistant cultivars in different parts of the world. Resistant cultivars are of particular interest because there is no other effective means of controlling this disease.

The Sub-Group objectives were:

1. To investigate the apparent anomaly that the most widely used source of resistance, derived from T.I.448A, does not appear to hold up in some countries, notably South Africa.
2. To establish whether different bacterial types exist, based on host reaction.
3. To identify sources of resistance which will be useful to breeders.
4. To establish whether the T.I.448A-derived resistance is recessive, as reported.

This is the seventh report to be presented (Jack and Robertson, 1995, 1996, 1997, 1998; Jack, 1999, 2000), covering the results from the 1999/00 and 2000 seasons.