Abstract:

Pollen morphology of 17 original Malus species and 25 ornamental crabapple cultivars were observed using environment scanning electron microscope. The results indicated that the apple pollen belonged to the N₃P₄C₅ type, bilateral symmetry, prolate sphericity or ultra prolate sphericity, with three germinal furrows extending almost to the full length of the grain. The exine surface had a striate pattern and some small pores. From the UPGMA cluster analysis, the 42 taxa could be classified into four groups. The first group contained M. florentina, M. sylvestri, M. 'Robinson' and other 7 cultivars. The second group included M. baccata and other 8 species and 3 crabapple cultivars, like M. 'Hopa'. The third group consisted of M. sieversii and 3 more species and cultivar M. 'Dolgo'. The last group comprised of M. coronaria, M. platycarpa M. 'Kelsey' and 13 more crabapple cultivars. Twenty-five ornamental crabapple cultivars originated from a very complicated genetic complex, which could be stated as cross-hybrids from species from North America, Europe, and Asia.

Key words: Malus, pollen, ESEM, cluster analysis, group