Example 11
Media is selected for use and kill curves developed as specified above. For selection, different techniques are utilized. Either a step wise selection is applied, or an immediate lethal level of herbicide is applied. In either case, all of the calli are transferred for each new round of selection. Selection is 4-5 cycles of culture with 3-5 weeks for each cycle. Cali are placed onto nylon membranes to facilitate transfer (200 micron pore sheets, Biodesign, Saco, Maine). Membranes are cut to fit 100×20 mm Petri dishes and are autoclaved prior to use 25-35 calli (average weight/calli being 22 mg) are utilized in every plate. In addition, one set of calli are subjected to selection in liquid culture media with weekly subcultures followed by further selection on semi-solid media. Mutant lines are selected using saflufenacil, 1,5-dimethyl-6-thioxo-3-(2,2,7-trifluoro-3-oxo-4-(prop-2-ynyl)-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-1,3,5-triazinane-2,4-dione (CAS 1258836-72-4/trifludimoxazin), flumioxazin, butafenacil, acifluorfen, lactofen, bifenox, sulfentrazone, and photosynthesis inhibitor diuron as negative control. Efficiencies of obtaining mutants is high either based on a percentage of calli that gave rise to a regenerable, mutant line or the number of lines as determined by the gram of tissue utilized.
