Phenotypic Differences Between Natural and Induced Variants of Botrytis cinerea

Abstract

Wild isolates of B. cinerea were analyzed to assess their suitability for genetic studies. When compared on synthetic and artificial media under laboratory conditions the isolates differed in rate of growth, conidiation, sclerotia production and resistance to benomyl. Asexual progeny of individual cultures were sometimes phenotypically diverse; they could be heterokaryotic or heteroplasmic. Attempts to derive auxotrophic, nystatin-resistant and benomyl-resistant mutants from mutagen-treated conidia were not successful; only morphological and spore color variants were recovered, and most of the morphological variants were phenotypically unstable. Cultures produced macroconidiophores and microconidiophores. Macroconidia were about 10 .mu.m long .times. 8 .mu.m wide, contained 1-12 nuclei (mean 3.4) and usually germinated readily on agar media. Microconidia were about 3 .mu.m diameter, uninucleate and rarely germinated on agar media. The perfect state, B. fuckeliana, was not recovered from mixed inocula of the wild strains. The significance of the results, the use of B. cinerea for laboratory studies and the possible genetic basis of natural variations are discussed.