Banana improvement through gamma irradiation and testing for banana bract mosaic virus in Sri Lanka

Abstract

Uwuinu is the most widely consumed fruit in Sri Lanka, and is an attractive perennial fruit crop for small farmers. I In:, is due to its high economic gains throughout the year compared with rice. Lowland rice fields have been ii in verted for banana cultivation. Among the local cultivars, Embul (Mysore, A A B ) is in the highest demand for Cultivation. Since 1990, the University of Colombo has carried out research on bananas, including micropmpagation through shoot-tip culture, gamma radiation-induced mutations, cell-suspension cultures and somatic pinluyogenesis, and ploidy analysis for detection of variation. Since 1995, investigations have been conducted to improve both Embul and Cavendish banana cultivars. Two selections of banana have been made for early fruiting and short height. Micrcpropagated plants of the selections were tested for trait stability until the second generation. Mass production of plants is in progress. Thus, indexing ind testing of plants for viruses, i.e. BBrMV and BSV, has become essential, since virus-free indexed mother stocks are required for micropropagation. Techniques were adopted for routine testing of mother stocks, and rnndom testing of micropropagated plants for BBrMV by DAS-ELISA with imported commercial kits. The present study was aimed at the development of a low-cost ELISA detection kit. Anti-serum for BBrMV, produced by the Queensland Department of Primary Industries (QDPI), Australia, was tested as the coating nntibody to replace the Agdia commercial kit. Results showed a relatively high efficiency with the QDPI antibody. Work is also in progress to make an alkaline phosphatase-conjugated antibody to replace the test kit. With the production of local antiserum, it is expected that an effective low-cost local diagnostic kit could be developed for the routine indexing of banana plants for BBrMV. This would facilitate the identification of virus-free mother slocks for micropropagation. However, purification of the virus extract is still a limiting factor for obtaining the untigen.