, there is little information available on ploidy levels of specific cultivars. Pseudogamy, a form of apomixis, has also been implicated as the sole means of reproduction in triploid R. triloba ( McCrea, 1981 ). A greater understanding of reproductive
, pharmaceutical, and agricultural improvement of plants ( Ascough et al., 2008 ). For instance, increased ploidy level was associated with increased flower size in rhododendrons and intensified flower colors in carnation and cyclamen ( Takamura and Miyajima, 1996
, 2010 ). Some effects of increasing ploidy level in woody ornamental species include darker green, thicker leaves and increased number of petals per flower in Rosa ( Kermani et al., 2003 ), thicker leaves and larger, more persistent flowers in
the identification of ploidy level by flow cytometry (FCM) (PAI; Partec, Münster, Germany); Rosa victoriana (2 n = 2 x = 14) was used as a standard plant. Nuclei were extracted from leaves according to Yokoya et al. (2000) . Leaf material from the
these objectives, progeny of commercial cultivars from self-pollination (SP) and OP were first analyzed for ploidy levels, followed by controlled pollinations among cultivars and breeding lines and ploidy analysis of their progeny. This report presents
, there have been no reports of successful hybridization between P. lusitanica and P. laurocerasus . We believe this apparent sexual incompatibility is likely due, at least in part, to the difference in ploidy level. Prunus laurocerasus is a 22-ploid
lantana cultivars that are used in the landscape. Several researchers have attempted to understand the relationships between ploidy level and fruit or seed production in L. camara . Natarajan and Ahuja (1957) suggested that ploidy level would be an
seedlings were untreated and were assumed to be diploid. Ploidy assessment. When seedlings had grown sufficiently to provide 0.3 g leaf tissue (6 to 12 weeks from transfer to the maturation medium), the nuclear DNA contents of treated and control
main factors that affect haploid induction. Tested doses ranged between 25 and 400 Gy with the optimum found to be below 100 Gy. Confirmation of the ploidy level of regenerants was well described by chromosome counting, stomata and chloroplast
microscope as described previously for stomatal parameter determination. Flow cytometry analysis. Ploidy analysis was performed on both control plants and progeny of the suspected tetraploid using flow cytometry. Young, unexpanded leaf tissues were collected