Abstract: The present invention relates to novel breadmaking yeast strains which are effective on non-sweetened and/or slightly sweetened products. It also relates to the yeasts obtained by a multiplication of said strains and also to the use thereof for the production of baked bakery products. The strains of the invention, selected after mutation in particular of a reference strain, are capable of multiplying according to a process that is slower than that of the reference strain, while exhibiting improved properties, in particular a fermentative capacity, compared with those of the reference strain.