Plant Breeding TISSUE AND CELL CULTURE AS AIDS TO SUGARCANE BREEDING. 111. ANEUPLOID CELLS AND PLANTS INDUCED BY TREATMENT OF CELL SUSPENSION CULTURES WITH COLCHICINE

Cell suspension cultures derived from 8 sugarcane (ISaccharvm species hybrid) varieties were studied. Chromosome numbers (2n) varied from 92 to 191, with a mean at 111, in cells of a colchicine-free suspension culture of F 164 of which the donor's number was 108. The numbers rose to as many as 309 when the cells were treated with 100 ppm colchicine. Similar results were observed for other varieties. Ten percent of pieces of colchicine-treated calli could be differentiated into plants. In total, 182 regenerated plants were obtained. Only 10 of them, derived from 61-1248, showed drastic morphological alterations equivalent to a 5.5% mutation rate. All of the variants were stunted in appearance and had stiffer leaves. Their chromosomal constitution was of aneuploid type with metaphase numbers around 2n = 156 which were much higher than their donor's number, 104. In the esterase zymograms-they had fewer bands than their donor. This confirms the observation that drastic morphological changes are associated with aberrations in chromosomal constitution and/or isoenzymatic patterns. It is suggested that the aneuploid plants can be utilized as parents in a sexual breeding program or in making crosses among.themselves so that hybrid vigor might be created.