RESPONSE OF CULTIVARS AND BREEDING LINES OF LYCOPERSICON SPP, TO ALTERNARIA-SOLANI

From 1990 to 1995 more than 650 tomato cultivars, breeding lines, and accessions of related species, were evaluated for resistance to early blight, caused by Alternaria solani. The levels of resistance for sele cted test lines are reported here. Promising material for use in early blight resistance breeding programs include the moderately resistant tomato breeding lines HRC90.145, HRC90.158, and HRC90.159 and the inte rspecific breeding lines HRC90.303, HRC91.279, and HRC91.341. Only lim ited success has been attained in incorporating resistance from the Ly copersicon hirsutum and L. peruvianum lines showing very high levels o f resistance. The L. hirsutum lines LA2100, LA2124, and LA2204 have sh own promise in producing interspecific lines in which the association between disease resistance and detrimental horticultural traits has be en weakened.