Data/hora: 03/06/2024 12:21:50

Biblioteca(s): | Embrapa Mandioca e Fruticultura.
Data corrente: | 15/04/2004
Data da última atualização: | 15/04/2004
Autoria: | JORGE, M. A; ROBERTS, A.
Título: | Factors affecting the acclimatization of ex-vitro cassava.
Ano de publicação: | 1998
Fonte/Imprenta: | Revista Brasileira de Mandioca, Cruz das Almas, v.17, p.53, nov., 1998. Suplemento.
Idioma: | Inglês

Conteúdo:

Abstract: In the semi-arid regions acclimatization process from tissue culture to the field is a problem compared to the humid tropics. The reasons are a long dry atmosphere and both diurnal and annual temperature range (from frost to 40°C). Previous data from trials of cassava (Manihot esculenta Crantz) in Mozambique, where IITA methods were compared to a locally adapted method, were not very successful, with 35% survial with adapted. IITA method. Studies to improve survial of ex vitro plantlets are still ongoing. Results are presented that include comparisons of light intensity levels in k-.he laboratory (64, 124, 205, 285, and 368 mEs-¹ m-²). Levels of fertilizer (NPK 94-253-51) (0,0.5,1,1-5 and 2.0g/    
1), types of substrate, namely milled pine bark, vermiculite, and theree mixtures (1:1:1) of river sand, red too soil, and compost (mushroom rose bush or grass) plus size of plants (from 2 through to 8 cm) were examined in the greenhouse. In the laboratory both low and low and intermediate levels (64-205 mEs-¹ m-²) during micropropagation gave the best survival rates, around 42-48% on acclimatization where as higher levels (285-36 mEs-¹ m-²) were only 8-12* survived. Milled pine bark has been the best substrate so far, it had the best survival rate (50%) and plant growth. Surprisingly fertilizer did not improve the survival rate and as the trial continued  to 8-12 weeks, it was eve-a detrimental to the plant survival and growth. They become fragile and more prone to insect attack, particulary during the critical hot and dry summer period. Plant size did not affect the survival rate, although the bigger ones had larger plants, more nodes and thicker stems. Considering these results we suggest low level of light (64 mEs-¹ m-²) during micropropagation, milled pine bark as a substrate for greenhouse trials, plants from the intermediate size (4 - 5 cm) and no use of fertilizer.

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Registro original: | Embrapa Mandioca e Fruticultura (CNPMF)
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