Polyploidy in tulips (Tulipa L.). The occurrence of diploid gametes

Summary From data available in the literature and supplemented by information from private tulip breeders, it appeared that triploid and tetraploid varieties raised in the past, resulted from crosses between diploid tulips and between diploids and tetraploids. This can only be explained by the occurrence of diploid gametes in diploid (2n=24) cultivars. This phenomenon which may affect both female and male gametes, appears to be specific for certain varieties. Consequences for practical breeding are discussed.