Development of embryos and plantlets of Coffea arabica L. by direct Somatic Embryogenesis / Desenvolvimento de embriÃes e plÃntulas de (Coffea arÃbica L.) oriundas de embriogÃnese somÃtica direta

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Coffee breeding programs have incorporated, by means of artificial crossings, genetic benefits for productivity and other characteristics of agronomic interest. The introduction of biotechnology methods to aid genetic breeding programs has demonstrated to be very much useful, mainly in perennial cultures, as it is the case with the coffee species. An important method of in vitro propagation of Coffea plants is somatic embryogenesis. Therefore, this work aimed the development of embryos and plantlets of Coffea arabica L. cv. Rubi by direct somatic embryogenesis. The influence of NH4NO3 (0%; 25%; 50%; 75% and 100%) x KNO3 (0%; 25%; 50%; 75% and 100%) as well as sucrose (0; 15; 30; 45 and 60mg.L-1) x GA3 (0; 2,5; 5 and 10mg.L-1) were tested for the development of somatic embryos in a diverse set of combinations of these media components. To achieve the most adequate culture medium formulation for the plantlets development, it was evaluated the influence of different types of culture media (MS; Knudson; WPM; White) x Ãgar (0; 2; 4; 6 and 8g L-1) and the influence of GA3 (0; 2,5; 5; 10mg.L-Â) x NAA (0; 0,25; 0,5; 1; 2mg L-Â) over the development of the young formed embryos. The experiments were maintained in a growth room under light intensity of 32ÂMol m-2 s-1, 25Â1oC and 16 hours of photoperiod. The characteristics evaluated were: number of leaves, length of the aerial part and fresh mass of the plantlets. For the plantlets acclimatization process two substrate types were tested (Plantmax  and Plantmax  carbonized rice husk (50%)) x slow liberation fertilizer (0, 0,5, 1 and 2g of the fertilizer per cell). The results indicated that it is possible to obtain micropropagated plantlets of Coffea arabica L. cv. Rubi by direct somatic embryogenesis. For the development of somatic embryos, the use of 50% of NH4NO3 and KNO3 is efficient for leaves induction. The absence of these salts provided the best weight of the plantlets. The use of 6mg L-1 of GA3 provided the best development in terms of length of the aerial part. In order to obtain coffee tree plantlets with high efficiency the WPM culture medium with 10mg L-1 of GA3 and 1mg L-1 of NAA presented the best results. The concentration of 1,5mg L-1 of agar provided the largest number of leaves as well as the biggest length of the aerial part. The best weight was obtained in the absence of agar.

ASSUNTO(S)

embriogÃnese somÃtica coffee fitotecnia aclimataÃÃo growth crescimento cafeeiro somatic embryogenesis acclimatization

ACESSO AO ARTIGO

Documentos Relacionados