Técnicas de cultivo in vitro e microenxertia ex vitro visando a eliminação do Cowpea Aphid-Borne Mosaic virus em Maracujazeiro-Azedo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The sour passion fruit plant (Passiflora edulis Sims f. flavicarpa Deg.) is one of the most important Brazilian fruitbearings and its cultivation presents good perspectives of expansion. The culture development has been made more difficult by diseases, specially the fruit hardening disease, caused by the Cowpea aphid-borne mosaic virus (CABMV). The virus elimination by tissue culture has been a viable alternative for many species and can contribute to the superior genotypes vegetative propagation. This work was performed with the objective of studying the in vitro organogenesis in yellow passion fruit plants infected with the Cowpea aphid-borne mosaic virus (CABMV) and assessing the effect of the culture medium used over the grafting spot in ex vitro micrografting aiming at eliminating the CABMV virus. In the organogenesis study five accessions were evaluated: MAR-2003, MAR-2021, MAR-2024, MAR-2048, Rubi Gigante (RG) and four sources of explants: cauline apex, internodal segment, nodal segment and foliar fragment. It was used for induction the medium MS supplemented by 2 mg.L-1 6-benzylaminopurine (BAP). The nodal segment presented the best cultivation performance while the worst results were obtained with the foliar fragment. The accessions presented similar behavior in relation to the percentage of organogenic explants and to the production of shoots. It was observed in histological cuts meristemoids in nodal and apex explants. In the work involving the virus elimination through ex vitro micrografting, stem apexes originated from MAR 2050 accession infected plants were micrografted in seedlings obtained through the germination of seeds and cultivation in commercial substract under laboratory conditions. Experiments were conducted with the micrografting performed on the hypocotyl and epicotyl. Five culture media were tested as adjuvant, applied at the grafting spot. The average rate of setting was 27.22 % when the micrografting was performed on the hypocotyl and 32.22 % when performed on the epicotyl. The micrografting performed on the hypocotyl showed no effects with the application of culture media or growth regulators. The micrografting performed on the epicotyl and the MS medium supplemented with 3% sucrose, 10 mg.L-1 thiamine; 1 mg.L-1 pyridoxine; 1 mg.L-1 nicotinic acid; 100 mg L-1 mio-inositol and 2 gL-1 Phytagel, (basic medium), in addition to 0.1 mg.L-1 3-indolbutiric acid (AIB) and 1 mg.L-1 6- benzylaminopurine (BAP) provided 53.3% setting in the micrografting and was superior to xviii the other treatments, excepting the basic medium treatment supplemented with 2 mg L-1 BAP. The same treatment provided larger shoots development. The beginning of the vascular connection formation between the participants was observed within 15 days and was established in 30 days. The indexation performed by the ELISA (Enzyme Linked Imunosorbent Assay) indirect test within 80 to 100 days of the micrografting showed that 93 % of the plants tested did not present detectable virus.

ASSUNTO(S)

eliminação de vírus passiflora edulis sims f. flavicarpa deg. organogênese in vitro. virus elimination passiflora edulis sims f. flavicarpa deg. in vitro organogenesis. ciencias agrarias micrografting microenxertia

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