THE EFFECTS OF ANCYMIDOL, ABSCISIC-ACID, UNICONAZOLE AND PACLOBUTRAZOL ON SOMATIC EMBRYOGENESIS OF ASPARAGUS

The effects of ancymidol, abscisic acid (ABA), uniconazole, and paclob utrazol on asparagus somatic embryogenesis were evaluated. Calli induc ed from seedlings of genotype G447 were transferred to embryo inductio n medium (MS plus 3% sucrose, 0.1 mg L(-1) NAA, 0.5 mg L(-1) kinetin a nd 3% gelrite), with different concentrations of these compounds. Afte r 8 weeks, the recovered bipolar or globular embryos were placed on ge rmination medium (MS plus 6% sucrose, 0.1 mg L(-1) NAA, 0.1 mg L(-1) k inetin, 0.75 mg L(-1) ancymidol, 40 mg L(-1) adenine sulphate dihydrat e, 0.17 mg L(-1) sodium phosphate monobasic and 3% gelrite) for conver sion to plantlets. Inclusion of ancymidol, ABA, uniconazole and paclob utrazol in the embryo induction medium did not affect the total number of somatic embryos produced relative to the control without these com pounds. However, ancymidol, ABA and uniconazole significantly improved embryo development by increasing the production of bipolar embryos 25 0-750% and decreasing that of globular embryos 8-35% relative to the c ontrol. The bipolar embryos produced with any of the four compounds in the embryo induction medium converted to plantlets at rates 700-1100% greater than the control. None of the globular embryos converted to p lantlets. Ancymidol (0.75 mg L-L) and ABA (0.05 mg L(-1)) were the mos t effective treatments; 61 and 46 bipolar embryos g(-1) callus were pr oduced, and 38% and 37% of the bipolar embryos converted to plantlets, respectively. These results indicated that ancymidol, ABA, uniconazol e and paclobutrazol significantly enhanced the production of asparagus somatic embryos and their conversion to plantlets, and ancymidol and ABA were more effective than uniconazole and paclobutrazol.