Tissue necrosis prevention during shoot multiplication of coconut.

The demand for coconut products, such as coconut-oil, -water and -milk, is rising worldwide. However, coconut production is currently not able to keep up with the demand due to ageing plantations, pests, and diseases. Large quantities of highly producing, disease resistant and drought tolerant coconut plantlets are therefore urgently needed. We developed an innovative clonal micropropagation method, that enables mass production of desired cultivars. With current in vitro methods and during the propagation phase, tissue browning or necrosis of parts of the proliferating material occurs routinely. We demonstrate that the addition of 1 g L 1 activated charcoal (AC)prevented shoot propagation. Therefore, we opted for components that do not interfere with the plant growth regulators present in the medium, such as ascorbic acid, which prevents oxidation and silver thiosulfate, an ethylene inhibitor. While different concentrations of ascorbic acid were shown not to affect tissue necrosis, increasing concentrations of silver thiosulfate prevented more tissue necrosis. Tissue necrosis mostly started 4-5 weeks after subculture, suggesting that shorter subculture cycles could also help mitigate this problem.