Optimization of indigenous Ganoderma lucidum

Abstract

Ganoderma lucidum is a mushroom which shows antitumor, anti-inflammatory and cytoxic activity and grows prolifically in warm climates on decaying hardwood logs and stumps. An experiment was done at the University of Namibia to cultivate the indigenous G. lucidum; however, compared to results from other countries the mushroom took much longer to grow. The objective of this study was to shorten the cropping cycle of the indigenous G. lucidum under cultivation at the University of Namibia. The indigenous mushroom was cultivated according to the established protocol. A suitable indigenous Ganoderma mushroom was selected to make tissue culture, which was used to make the spawn that was inoculated into the woodchips substrate. New ideas were introduced to induce fast growth and optimum yield. The grains were inoculated with more pieces of tissue culture; the substrate was inoculated with increased layers of spawn and mixed with pearl millet husk instead of wheat bran to accelerate the colonization of the substrates. In addition to the hanging bag method used in the previous study, the buried wood log method was also introduced. Temperature and moisture were closely controlled during the experiment. A major highlight of this study was the significant reduction (p < 0:05) in the time it took for the substrate to reach fruiting stage. The substrate mixed with pearl millet husk was completely colonized by the mycelia, two weeks faster than the substrate that was mixed with wheat bran. Since Pearl millet is readily available in Northern Namibia, individuals and communities can substitute the wheat bran with pearl millet husk, which allows the substrate to be ready for fruiting faster, thus shortening the cropping cycle and also reducing the production cost as they no longer have to purchase wheat bran. The buried wood logs did not yield any fruiting bodies, but the hanging bags did produce G. lucidum. The study was successful in producing fruiting bodies in a shorter period. There was no significant improvement in the yield obtained.