4.1.2
INITIAL SCREENING OF ACCESSIONS OF SOLANUM (EGGPLANT) FOR RESISTANCE TO LEAF SPOT DISEASES CAUSED BY CERCOSPORA MELONGENAE AND CERCOSPORA DEIGHTONII

S AKROFI

Plant Genetic Resources Centre, Bunso, Ghana

Background and objectives
The Plant Genetics Resources Centre at Buso in Ghana is mandated with the collection and conservation of the genetic resources of the country. A wide range of Solanum species was collected in a germlasm-collecting expedition undertaken in the country in 1996. These comprised S. aethiopium, S. gibo, S. macrocarpon and S. melongena. An evaluation programme was initiated to identify accessions with resistance to Cercospora melongenae and C. deightonii, the two leaf spot pathogens that infect the crop in the area.

Materials and methods
Sixty-five accessions of eggplant consisting of S. gibo (54 accessions), S. aethiopium (seven accessions), S. macrocarpon (one accession) and S. melongenae (three accessions) were screened for the two leaf spot diseases in the field under natural conditions. Disease scoring was based on the International Board of Plant Genetic Resources (IBPGR) scale, where 1=extremely low susceptibility and 9=extremely high susceptibility.

Results and conclusions
The susceptibility of most of the acessions to the two leaf spot pathogens highlighted the need to identify sources of resistance. Two accessions of S. gibo and one accession of S. melongenae had no incidence of either disease. Seven accessions of S. gibo and one accession of S. aethiopium had low susceptibility to both pathogens. Two accessions of S. gibo were free of the symptoms of S. deightonii. Accessions that had low disease scores in this trial have been selected for further screening.