Viabilidade polínica e propagação in vitro de Etlingera elatior (Jack) R.M. Smith

Abstract

The Etlingera elatior is a tropical perennial and rhizomatous herbaceous plant that possesses beautiful flowers with different colors and a great ornamental appeal. To produce new cultivars it is necessary crossings between existing varieties which are rare for this species. Among the difficulties found to grow Etingera elatior is the acquisition of quality seedlings with appropriate sanitary standards to supply the demand of the producers. Another considerable problem is the seedlings production that, usually made by bunch division, brings high costs and disease problems. This work aimed to evaluate the viability of the pollen grains in flowers of the Red Torch, Pink Torch and Porcelain cultivars to be used in a future breeding program to create new commercial types of the Etlingera elatior, and developing a protocol for multiplication in vitro of Etlingera elatior cv. Red Torch. Therefore, it was carried out an study to check the viability of the pollen grains in open and closed flowers of small, medium and tall stick flowers. The pollen grains were stained in a lugol solution and observed on a stereoscopic microscope. The micropropagation potential was evaluated by testing the effects of 6-benzilaminopurine alone in different concentrations (1, 2 e 3 mg.L-1) the germination of zygotic embryos and the micropropagation of the explants from in vitro germinated seeds, or combined to kinetin or naphtalenacetic acid in the in vitro multiplication of the explants. The percentage of stained pollen grains above 99%, showed that no effect of the cultivars, size of the sticks flowers or aperture of the flowers was observed, indicating that pollen viability is not the cause of the low fruit formation in this species. The largest number of sprouts (7,86) was obtained in a MS medium culture enriched with 3 mg.L-1 BAP. In the absence of hormones the explants showed the highest sprouts length, roots number and length. The acclimatization of the explantes at a glasshouse presented a satisfactory rate (>80%) of plant set, and after 60 days they were ready to be transported to the field.