Propagação in vitro e aplicação de termoterapia e crioterapia visando limpeza viral em Hippeastrum hybridum Hort. cv. ‘apple blossom’

Abstract

Hippeastrum (Hippeastrum hybridum Hort.), an herbaceous plant native to South America, is among the outstanding ornamental species in the Brazilian florist sector. Currently, the prices practiced in the Brazilian market for some amaryllis varieties commercialization, standing out the cv. 'Apple Blossom' are considered high. The high prices are mainly due to the low rate of vegetative propagation and losses related to bulbs virus contamination, where the symptoms usually manifest themselves after budding, leading to viral proliferation throughout the production by means of insect vectors. Considering the inefficiency of the traditional method for viral elimination, cryotherapy appears as an alternative to intensify the elimination of pathogens in infected plant tissue. In cryotherapy, the biological material is immersed in liquid nitrogen (NL) for a short period, usually 90 minutes and in these conditions, the infected cells are eliminated, conserving only highly cytoplasmic cells in the meristematic region, which remain alive due to the use of procedures that prevent intracellular water crystallization. Thus, in order to multiply large-scale elite genotypes in reduced physical space and time, it is essential to apply tissue culture techniques for in vitro species propagation, in addition to establishing a protocol for cryopreservation of amaryllis buds cv. 'Apple Blossom', aiming at the elimination of viral complexes.