Biologia reprodutiva, embriogênese gamética e somática em cultivares de amarílis (Hippeastrum sp. Herb.)

Abstract

The genus Hippeastrum sp. is popularly known as amaryllis and its production is intended for the market of potted flowers. With a wide variety of hybrids, its spread is made from bulbs. Nevertheless, there are major phytosanitary barriers to its production due to this type of propagation. Therefore, the objectives of the present work were: to characterize and evaluate the pollen viability of different cultivars of amaryllis; to obtain haploid and / or double-haploid embryos through gametic embryogenesis, aim at genetic improvement and developing an in vitro propagation protocol through somatic embryogenesis techniques. For the characterization, the length of the inflorescence, the number of flower buds per inflorescence, the floral opening diameter and the coloration were evaluated. The conservation of pollen viability was evaluated at different temperatures (-20, 8 and 25 ° C) for 245 days. In the gametic embryogenesis, anther culture techniques were used in five cultivars: 'Apple Blossom', 'Bull', 'Olaf', 'Super Star' and 'Cough'; in ovary culture, the cultivars were: 'Intokazie', 'Olaf', 'Orange Souvereign' and 'Super Star'. In the gynogenesisi in situ, different irradiation doses (0, 40, 80, 120, 160 and 200 Grays) were tested in the cultivars' Intokazie ',' Olaf ',' Orange Souvereign 'and'Pink Panther'. For the induction of somatic embryogenesis, petal segments of five cultivars of amaryllis and inoculated in MS ½ culture medium containing different combinations of 2,4-D and TDZ were used. The characterization of the cultivars showed difference between flowering and mainly in relation to coloration. The temperature of -20ºC was that the best kept the pollen viability of the cultivars. For both anther culture and ovary culture, there was no response of the material to the formation of callus or embryo. The obtained seedlings were evaluated by means of flow cytometry. It was found that irradiation doses at 40 and 80 Grays were the ones that presented better induction of haploidy. The 'Bin' cultivar presented the highest induction rates (48%) in the concentration of 0.5 mg L-1 of 2,4-D and 1,0 mg L-1 of TDZ. The other cultivars had the best rates of induction of somatic embryos in the concentration of 0.5 mg L-1 of 2,4-D and TDZ. For all experiments, the genotype was the most influential fact.