Determination of ploidy level of Hippeastrum sp. by Feulgen staining method

Przemysław Marciniak 1 Agnieszka Marasek-Ciołakowska 2 Dariusz Sochacki 1

1Warsaw University of Life Sciences, Department of Ornamental Plants, Warsaw, Poland
2The National Institute of Horticultural Research, Skierniewice, Poland

Hippeastrum sp. (Amaryllidaceae) is an ornamental bulbous plant native to tropical and subtropical regions of America.  It is used worldwide as a cut and potted flower with showy large flowers of various colors. Two genotypes of Hippeastrum ×chmielii (bred by Henryk Chmiel at the Warsaw University of Life Sciences in 1993) and three commercial cultivars of H. hybridum were tested. The aim of this study was to evaluate the applicability of Feulgen staining of metaphase chromosomes to determine the ploidy level of clones 6 and 18 of H. × chmielii and cultivars 'Gervase', 'Rio Negro' and 'Royal Velvet'. After modifying the maceration time of root meristem cells in 1N HCL, the usefulness of the method to determine the ploidy level of the genotypes studied was demonstrated. The base chromosome number of each genotype was x=11, cultivar ‘Rio Negro’ was diploid (2n=22) and the others genotypes were tetraploid (2n=44).