SCREENING FOR RESISTANCE TO ANTHRACNOSE (COLLETOTRICHUM-GLOEOSPORIOIDES PENZ) IN ALLIUM-CEPA AND ITS WILD RELATIVES

Colletotrichum gloeosporioides is an airborne disease which causes sig nificant yield losses in shallots (A. cepa var. ascalonicum) grown in the tropics. Breeding for resistance to this disease in shallots has b een scarcely carried out and has been primarily focussed on Allium cep a material. Wild species related to shallot might provide sources of r esistance and therefore a screening of this material was carried out. Three different isolates of C. gloeosporioides originating from Brazil , Nigeria and Indonesia, were used in the screening procedure. The acc essions screened of A. cepa and A. oschaninii were most susceptible to the three isolates. Partial resistance was observed in accessions of A. altaicum, A. fistulosum, A. galanthum, A. pskemense and A. roylei. The highest level of resistance was found in accessions of A. galanthu m and A. fistulosum, A. roylei was highly resistant to the Brazilian i solate but very susceptible to the Nigerian and Indonesian isolates. A genetic analysis of the resistance present in A. roylei to the Brazil ian isolated revealed that it is dominantly inherited and most probabl y determined by more than one gene.