SOMATIC EMBRYOGENESIS IN MACAW PALM FROM INFLORESCENCES OF DIFFERENT MATURITY LEVELS.

The only possibility for cloning elite genotypes is somatic embryogenesis using maternal tissues as explants, such as inflorescences (rachillas). In this work, we evaluated the effect of the level of maturity of the rachillas (size) and the concentration of auxins on the induction of somatic embryos (SE) in a genotype selected by our breeding program. Rachillas of different sizes were extracted from the respective bunches and measurements before being distributed on plates containing Y3 medium supplemented only with Picloram (150 or 200mg. ^L-1) or with 100mg. ^L-1 of each auxin (PIC + 2.4D) for callus induction. After 180 days (with monthly subcultures) or 270 (without subculture), the calluses were transferred to the same medium, but with 1/4 of the auxins aiming to induce SSc. Only rachides smaller than 1.5 cm formed nodular embryogenic calluses. Translucent or white globular structures correspondent to SE appeared in these calluses at 180 days of cultivation. Calluses from 0.4 cm rachylas (Ch-4), when in medium with 1/4 auxin induced a higher average of ES per explant (5.5). Only 10% of these ES were in the torpedo phase, but none of them germinated with a high oxidation index. However, when these calluses were kept in the dark for 270 days in initial medium and then transferred to medium with 1/4 auxin, there was a greater number of mature SE, which were individualized and germinated in medium without phytoregulators.