Quality planting materials for cassava industry development

摘要

Cassava is increasingly used by manufacturing industries for food and non-food uses. A major industry constraint is the consistent supply of the desired volume and quality of raw materials for processing. Yield is declining due to several factors including the emergence of new diseases. Several commercial ventures have resorted to the use of clean planting materials that can be rapidly produced through tissue culture techniques. Conventional propagation uses stem cuttings, which increase the pathogenload from one crop generation to the next usually without symptoms, thereby contributing to decreasing yield potential. Earlier work at PhilRootcrops established meristem culture and micropropagation protocols for production of clean planting material.In vitro culture responses were genotype specific but meristem-derived plants produced better plant stands and yield than conventional propagules when planted in the field. This research determined the suitability of an established protocol using Murashige and Skoog (MS) medium alone and modified protocols using different growth regulators for micropropagation of high-yielding cultivars newly approved for commercial release by the National Seed Industry Council. Tissue-culture-derived (TC) plantlets were then grown in the greenhouse for 3-5 months, and yield evaluation of the first- and second-generation TC plants was undertaken comparing two-nodal stem cuttings and the usual 8-inch stem cuttings. Results showed genotype-specific responses to in vitroculture conditions. Callus formation in 75-100% explants was observed in treatments with growth regulators. Root formation and growth were better in MS medium alone. Nodal propagation of 3- to 5-month-old potted TC plants was best in foam compared with other potting media as complete plantlets were produced in 2 weeks. Field performance and yield were comparable among the TC plants using two-nodal and 8-inch stem cuttings. This result indicates that two-nodal cuttings from clean TC plants are promisingpropagules to expand production and sustain high productivity.