SOMACLONAL AND CHROMOSOMAL EFFECTS OF GENOTYPE, PLOIDY AND CULTURE DURATION IN ASPARAGUS-OFFICINALIS L

Chromosome and morphological variations of embryogenic calli-derived p lants of gynogenic haploid, diploid, triploid and tetraploid asparagus (Asparagus officinalis L.) were investigated. Artificial tetraploids were produced using colchicine treatment of seeds of diploid cultivar, 'Poultom'. 'Haidel' (2X) was crossed with the artificial tetraploids, from which one gynogenic haploid, one diploid, 6 triploid, 3 mixoploi ds were obtained. Embryogenic calli were first obtained from crown bud s, subsequently induced to form somatic embryos, and after 30 days, in duced to germinate. Chromosome variation in embryogenic calli-derived plants increased with increasing duration of subculture, particularly when low ploidy levels of plants such as haploid and diploid were used as explants. Approximately 80% of haploid-derived plants showed morph ological variations such as dwarfness and abnormal morphological chara cteristics, although no differences were observed in cladodes and stem characteristics between other polyploid-derived plants and their pare nts. The data presented here would supply important fundamental inform ation for commercial mass-propagation using somatic embryogenesis.