CALLUS INDUCTION AND HAPLOID PLANT-REGENERATION FROM ANTHER CULTURE OF 2 POPLAR SPECIES

Anthers from 5 different clones of Populus nigra and Populus deltoides were isolated from dormant flower buds before catkin elongation and e xposition, in order to establish haploid and doubled haploid poplar pl ants in vitro. Isolated anthers were cold treated and placed on MS med ium supplemented with 2,4-D (0.5 mg/l to 2.0 mg/l) and Kinetin (0.1 mg /l to 1.0 mg/l). The optimal hormone concentration for callus inductio n was 1.0 mg/l of 2,4-D and 0.1 mg/l of Kinetin. The callus initiation response of the genotypes ranged from 24% to 75%. The genotypes with the best callus initiation response were P. nigra. N-90 (59%) and P. d eltoides D-29 (75%). Calli were subcultured on MS or WPM medium supple mented with BA (0 mg/l to 2.5 mg/l) and NAA (0 mg/l to 0.2 mg/l) for p lant regeneration. The highest shoot regeneration frequency (79%) was obtained after 2 subcultures on MS medium supplemented with BA (1.0 mg /l) and NAA (0.2 mg/l), and on WPM medium supplemented with BA (2.5 mg /l). The rate of shoot regeneration and number of shoots/calli ranged from 4% to 79% and 1 to 9, respectively.