Morphological and genetic diversity of breeding clones derived from Hippeastrum × chmielii

Hippeastrum is among the most widely cultivated geophytes, utilized for both cut flowers and potted plants. The range of cultivars is expanding, with an average of 33 new cultivars registered annually in the international register maintained by the Royal General Bulb Growers' Association in the Netherlands. This study focused on the morphological and genetic diversity of 15 Polish breeding clones derived from H. × chmielii and H. hybridum. The study encompassed phenotypic evaluation, assessment of the number and length of stomata, and the use of RAPD and ISSR markers across all genotypes examined. Phenotypic analysis, conducted in accordance with the descriptors of The International Union for the Protection of New Varieties of Plants (UPOV) and the RHS Colour Charts, facilitated the identification of three promising breeding clones. These clones (0037-13 with flowers of the greyed-purple colour group, 185A; 0021-10 with orange-red flowers, 34A; and 0023-11 with orange-red, 35B) produced a greater number of larger flowers than the maternal forms of H. × chmielii. The population exhibited significant variation in the number and length of stomata, with an inverse correlation between stomatal length and number. The use of RAPD and ISSR markers showed high genetic similarity between the initial forms and breeding clones in the range of 74-85%. The three selected Hippeastrum clones have the potential to become new cultivars originating from H. × chmielii.