Flow cytometry is a rapid method with many microbiological applications. This technique can be used to obtain counts of viable yeasts in 30 min, whereas a 48 h incubation is necessary with plate counts. This rapid method was tested for its suitability to analyse wine yeasts in a multicentre study in our three laboratories. The study compares measurements obtained by flow cytometry and the usual method, in order to test the reliability of the new method. The results obtained were very similar in terms of both the micro‐organisms detected and the precision of measurements.

The transfer of chromosomes from a laboratory strain FLO5 to a wine strain using cytoduction yielded flocculent clones. The fermentation performance of such clones was closely correlated with the quantity of genetic material transferred. The fermentation properties of clones receiving only a single chromo some I were very similar to those of the original strain. The transferred chromosome I was more stable when it replaced the original chromosome than when it remained as an additional element.