Avaliação de dois métodos para multiplicação in vitro de três variedades locais de mandioca (Manihot esculenta Crants)

Abstract

The present work aimed to determine the best culture medium and to evaluate its efficiency in the in vitro multiplication of three local varieties of cassava (Manihot esculenta Cranz). The experimental design used was completely randomized, 2x3, and two different culture media developed by the International Center for Tropical Agriculture (CIAT) and the International Institute of Tropical Agriculture (IITA) were tested, with three local varieties of cassava (Chinhembwe, Munhaça and Mz -89186) .In the method developed by CIAT, 20 g of sucrose, 0.10 g of monositol, 10 ml of thiamine-HCI, 0.4 ml of BAP, 0.5 ml of GA3, 0.2 ml of ANA and 10 ml of vitamins e were added to the MS medium. 6.0g of agar while the method developed by IITA the MS medium was added with 20g of sucrose, 010g of m-inositol, 10ml of thiamine-HCI, 5ml of BAP, 1ml of ANA and 10ml of vitamins and 6.0g of agar, distributed in tubes (2.5 cm in diameter x 15 cm in height) and autoclaved at 121 * C for 15 minutes. The explants were inoculated in a laminar flow chamber. After the inoculation process, the material was transferred to a growth room with 30 * C temperature and light (1,000 lux, 12/12 hours of light / dark). Three subcultures were carried out, in both methods, for all varieties. subcultures were carried out every thirty days. After 30 days, the numbers of mini-cuttings, weight of fresh matter of leaves and roots, number of leaves and roots, length of roots and height of the aerial part of the seedling were evaluated. The study resulted in the development and formation of seedlings in more than half of the stem segments regardless of the variety. The average multiplication rate was acceptable for the variety MZ-89186 in the method developed by IITA having presented an average number of mini-cuttings of 2, 8. Other acceptable levels achieved in the method developed by IITA for the variety MZ-89186 fpram: at the height of the seedling (4.3 cm), length of the roots (3.41 cm) and average weight of the fresh matter of the roots (0.348b) and for Chinhembwe variety were: number of roots (2.65), number of leaves (3.38) and weight of fresh leaf matter (0.0428). The results showed a high percentage of callus formation, observed in the method developed by CIAT, which may have negatively affected the multiplication rate. (TRADUÇÃO NOSSA)