Abstract

BILLARD, C.E.; DALZOTTO, C.A.  and  LALLANA, V.H.. Disinfection and asymbiotic sowing of orchid seeds. Polibotánica [online]. 2014, n.38, pp.145-157. ISSN 1405-2768.

Oncidium is a genus of orchids native to South America, as O. longicornu (A) present in SE Brazil and Argentina and O. bifolium var. bifolium, natural variations found O. bifolium of "yellow petals (B) and the "federal" O. bifolium variety (C). In seed planting orchid asymbiotic, disinfection is important to prevent contamination in the culture medium. Was sought to adjust the seed disinfection technique not applying the rinsing stage and evaluate germination in vitro. Murashige and Skoog semisolid medium was used in half concentration. Sodium hypochlorite was used to disinfect seeds in three doses: 0.5%, 1% and 2%. Also in O. bifolium "yellow petals", the effect of rinsing with sterile distilled water using sodium hypochlorite 0.5%. Was found the average viability of the seeds was 98% (tetrazolium test). Germination for Oncidium seeded occurred at 15 days. At 48 days of sowing time the 2% dose of said difference of 39% and 60% germination values with respect to viability in (C) and (B) respectively, while (A) difference was 9% and 0.5% dose was 18%. In O. bifolium "yellow petals" at 49 days of sowing time, visualized protocorms presence of white (dead), at 67 days their percentage was 14%, decreasing the germination of 84.4% to 73.2% without rinsing, while the seeds rinsed were no registered white protocorms. Is recommend concentration of 0.5% sodium hypochlorite and perform sterile water rinses to ensure a higher percentage of survival of protocorms.

Keywords : epiphytic orchids; disinfection technique; in vitro germination; viability.