How to cultivate Ganoderma lucidum with mango sawdust? Detailed technical points
1. Scion selection: Collect scions from a superior mother tree in a certified mother stock orchard or from outstanding individual adult trees. The mother plant must be of a pure variety, high-yielding, consistently productive, of high quality, and free of quarantine pests and diseases. Where conditions permit, nurseries should establish a scion orchard dedicated to supplying scions for collection. Select branches from the outer canopy facing the sun, vigorous, well-filled, with plump buds, and disease-free...
Ganoderma lucidum is a treasure of traditional Chinese medicine, long known as the "divine mushroom" and "auspicious herb." It is the collective name for all fungi in the genus Ganoderma (family Ganodermataceae), which in nature grow saprophytically on the decaying wood of broadleaf trees as their nutrient substrate. Ganoderma can be collected throughout the country, but due to excessive logging of forest vegetation, more and more wild species have become increasingly rare, and their numbers are increasingly depleted. Wild Ganoderma can be found distributed in Zhuhai, mainly growing on the dead wood of Taiwan acacia (Acacia confusa), chinaberry (Melia azedarach), and similar trees.For substitute substrate cultivation of Ganoderma, wood processing residues or agricultural by-products are usually selected and mixed with an appropriate amount of supplementary materials. Due to typhoon prevention and other reasons, Zhuhai prunes a large amount of wood from street and landscaping trees every year, and mango, as a native tree species of Zhuhai, is often chosen as a street and landscaping tree. To make fuller use of wood waste and turn waste into treasure, the author used mango as the main wood material for the Ganoderma cultivation substrate, adding cottonseed hulls, wheat bran, and other supplements in a substitute substrate cultivation method to grow Ganoderma, in order to determine a substrate formula with Zhuhai characteristics.
1 Materials and Methods
1.1 Overview of the experimental site
The research experiment of this project was set up at the Meixi Base of the Zhuhai Agricultural Science Research Center, located in southern Guangdong Province, with a southern subtropical monsoon climate, abundant sunshine, an average annual temperature of 22.4 °C, and an average annual relative humidity of 79%, suitable for year-round cultivation of Ganoderma.
1.2 Experimental materials
1.2.1 Sawdust raw material Mango wood from the widely planted landscaping tree species in Zhuhai was selected, with side branch diameter greater than 4 cm. The wood was harvested in May and June 2009 at the Meixi Base of the Zhuhai Agricultural Science Research Center and crushed into sawdust particles with a diameter of ≤5 mm.
1.2.2 Test strain The American large Ganoderma strain provided by the Strain Experiment Center of Huazhong Agricultural University.
1.3 Experimental methods
1.3.1 Mother culture medium PDA medium (1,000 mL): potato 200 g, glucose 20 g, peptone 1 g, monopotassium phosphate 1 g, agar powder 15 g, add water to 1,000 mL.
1.3.2 Stock culture medium Mango sawdust 73%, wheat bran 25%, calcium sulfate 2%.
1.3.3 Cultivation spawn medium According to mass ratio, among cultivation spawn medium treatments 1 to 6, the contents of mango sawdust, cottonseed hulls, and wheat bran were respectively: treatment 1, 39.5%, 39.5%, 20%; treatment 2, 59%, 20%, 20%; treatment 3, 69%, 10%, 20%; treatment 4, 69%, 20%, 10%; treatment 5, 79%, 10%, 10%; treatment 6, 89%, 0%, 10%. Each medium was additionally supplemented with 1% calcium sulfate, and the medium moisture content was 60%.
1.3.4 Cultivation management and statistics Cultivation bags of 17 cm × 30 cm polypropylene plastic (11230, -55.00, -0.49%) bags were filled with 1 kg wet weight of cultivation material, sterilized with steam at 121 °C and 0.15 MPa for 2.5 h. After cooling, inoculation was carried out in a double-head manner. After inoculation, the spawn bags were sealed and stacked neatly. After the mycelium fully colonized the bags, they were transferred to the fruiting room for bag-opening and fruiting management. The experiment was arranged from July to September, with an average temperature of 29.1 °C. Each treatment had 30 bags, with 3 replicates, and 10 bags were randomly selected for fixed-point observation and recording, recording mycelial growth rate, vigor, primordium formation time, fruiting body size, and shape. After harvesting, Ganoderma was dried and the dry mass was measured.
2 Results and Analysis
2.1 Effects of different media on Ganoderma mycelial growth
As shown in Table 1, among different media, there were obvious differences in mycelial vigor, growth rate, bag-full colonization time, and primordium formation time. Treatment 6 grew fastest, had the weakest mycelial vigor, and the shortest bag-full time, but the longest primordium formation time; treatments 5 and 3 grew relatively fast and had shorter bag-full times, with treatment 3 having better mycelial vigor than treatment 5 and a somewhat shorter primordium formation time; treatments 2 and 4 had slower mycelial growth and longer bag-full times, with treatment 2 having better mycelial vigor than treatment 4 and a somewhat shorter primordium formation time; treatment 1 had the slowest mycelial germination and growth rate and the longest bag-full time, but the best mycelial vigor and the shortest primordium formation time. These results indicate that wheat bran content plays a key role in mycelial vigor and primordium formation and cap opening. At 20% content, the mycelium was dense and robust, and the primordium formation and cap opening times were short; at 10% content, the mycelium was sparse, and the primordium formation and cap opening times were longer. When mango sawdust content was relatively high, mycelial germination and growth rates were faster and bag-full time was shorter, but because the gaps in the sawdust were relatively large, the mycelium was sparse, not compact, and uneven, and primordium formation time was delayed.
2.2 Effects of different media on Ganoderma fruiting body morphology
As shown in Table 2, among the 6 treatments, fruiting body shapes fell into 2 categories: the fruiting body caps of treatments 1, 2, and 3 were fan-shaped, lighter in color, with flat cylindrical stipes; the fruiting body caps of treatments 4, 5, and 6 were elliptical to round, darker in color, with slender cylindrical stipes. There were obvious differences in cap length, width, thickness, and stipe length and thickness. Cap length, width, and stipe thickness were all treatment 1 > treatment 2 > treatment 3 > treatment 4 > treatment 5 > treatment 6; stipe length was: treatment 6 > treatment 5 > treatment 4 > treatment 3 > treatment 2 > treatment 1; cap thickness was: treatment 6 > treatment 5 > treatment 4 > treatment 1 > treatment 3 > treatment 2. This indicates that wheat bran content also plays a key role in fruiting body cap morphology, which is consistent with the effect of wheat bran content on primordium formation and cap opening time. When wheat bran content was high, because cap opening occurred early, the caps were broad and large, and the stipes were shorter and thicker; when wheat bran content was low, cap opening was delayed, and the fruiting body shape was more similar to wild Ganoderma. In addition, as the ratio of mango sawdust to cottonseed hulls decreased, the caps gradually became smaller.
2.3 Effects of different media on Ganoderma yield and medicinal components
As shown in Table 3, the fruiting body yield and biological efficiency of each Ganoderma treatment were positively correlated with their shape and size, that is, treatments 1, 2, and 3 had relatively high dry mass of fruiting bodies, dry mass of spore powder, and biological efficiency, while treatments 4, 5, and 6 had lower values for these 3 indicators; however, in terms of medicinal active components, the 6 treatments showed no obvious differences in the contents of Ganoderma polysaccharides, total triterpenes, and germanium. To further explore the effects of different media on Ganoderma fruiting body yield, analysis of variance and Duncan's new multiple range test were performed on fruiting body dry mass, with the results shown in Tables 4 and 5.
The analysis of variance results showed that different media had an extremely significant effect on Ganoderma yield. The Duncan's new multiple range test results showed that there were extremely significant differences between treatments 1, 2, and 3 and treatments 4, 5, and 6, indicating that wheat bran content was the dominant factor in Ganoderma yield; while there were no significant differences among treatments 1, 2, and 3, and fruiting body yields were all relatively high, and there were no significant differences among treatments 4, 5, and 6, and fruiting body yields were all relatively low. As the proportion of sawdust increased, fruiting body yield decreased slightly.
3 Conclusions and Discussion
1) Using mango sawdust as the main material for Ganoderma cultivation, with a mass ratio between 39.5% and 79%, was suitable for Ganoderma growth, and there were no obvious differences in medicinal components among the treatments. Mycelial growth was rapid and fruiting body morphology was normal. As the main raw material for substitute substrate cultivation, the crushing quality of mango sawdust must be strictly controlled to achieve moderate size and uniform shape, so as to ensure consistent spawn bag quality. As a native tree species of Zhuhai, mango is often selected as a street and landscaping tree. In terms of Zhuhai's climatic conditions, mango can promote new shoot growth in all four seasons locally, with branch growth most vigorous in spring and summer. However, the vigorous canopy also creates difficulties for typhoon prevention and emergency response during typhoon season. Therefore, Zhuhai prunes a large amount of mango wood every year. By using mango sawdust as a Ganoderma cultivation substrate, local wood waste can be more fully utilized, turning waste into treasure while also saving production costs, achieving two benefits at once.
2) When the amount of wheat bran added to the medium reached 20%, the mycelium was compact and robust, primordium formation time was short, fruiting body caps were broad and large, and yield was high. This is related to wheat bran, as a supplement with high nitrogen content, being able to balance the carbon-to-nitrogen ratio in the substrate.
3) Among the main materials of the medium, mango sawdust and cottonseed hulls are both components with high carbon content, and their nutritional functions are the same. However, as the mass ratio of mango sawdust to cottonseed hulls increased, fruiting body shape and yield decreased slightly. This is mainly related to the physical properties of cottonseed hulls: they have good air permeability and strong plasticity, and can effectively fill the gaps in mango sawdust, making the medium appropriately loose and firm and mycelial growth uniform, which is more conducive to later mycelial growth and earlier primordium formation. Therefore, it is recommended that, on the basis of using mango sawdust as the main material for Ganoderma cultivation, an appropriate amount of cottonseed hulls be added as a buffer material, with a content of 5% to 10% being suitable.
4) The commonly used main and supplementary materials for Ganoderma cultivation include: Taiwan acacia sawdust, cottonseed hulls, corn (2349, 8.00, 0.34%) flour, wheat bran, etc. In the Zhuhai area, all of these must be obtained through procurement, logistics, and other channels, resulting in high production costs for the industry and raw material supply constrained by season. At present, the raw material cost of the formula widely used in the Ganoderma cultivation industry is about 1,400 yuan·t-1. Therefore, while selecting mango wood as the main substrate material, under the premise of ensuring product quality, the amount of various external materials added should be reduced as much as possible. It is recommended that the mango sawdust medium formula for Ganoderma cultivation in the Zhuhai area be: mango sawdust 69%, cottonseed hulls 10%, wheat bran 20%, calcium sulfate 1%, medium moisture content 60%, with mango sawdust crushed into particles with a diameter of ≤5 mm. The estimated cost of this formula is 600 yuan·t-1.