The objective of this work was to evaluate a mass micropropagation system for cassava (Manihot esculenta Crantz). Six varieties were used: Aipim-Rosa, Aipim-Maranhão, Cangaíba, Caravela, Cravela and Pretinha. Routine techniques of the Embrapa-Centro Nacional de Pesquisa de Mandioca e Fruticultura Tropical were used for meristem isolation, multiplication and plantlet acclimatization. After 30 days, 78% of meristems developed to plantlets. Independently of the variety and subculture, the average multiplication rate was 2.9, thus allowing the production of 231.2 plantlets per each initial explant, after five subcultures. Callus formation was high (22%), but did not affect the multiplication rate. Leaves presented normal shape, size and color. The average contamination rate (7%), losses by other factors (19%) and root formation (52%) were adequate. There was a strong influence of the genotype on the in vitro development of plantlets. 'Cangaíba' showed the highest multiplication rate, plantlet height and root formation per subculture, respectively of 3.6, 43.7 mm and 77%. The plantlets were easily acclimatized.
Manihot esculenta; plant propagation; tissue culture; in vitro culture
