Mushrooms can be cloned by taking a tissue culture and growing it in a sterile media made of potato dextrose agar solution, which provides the neccessary nutrients for the tissue culture to grow. A tissue culture requires that a sterile piece of the inside of the mushroom be taken from a host mushroom. The process is similar to taking a cutting from a shrub and rooting it. The tissue culture will grow mushrooms identical to the parent.
Slice unpeeled potatoes, place in the pot, cover with water and cook on medium high heat until the potatoes are tender.
Strain and place liquid from the potatoes in the Pyrex bowl. Mix in 28.4gr. of agar and 2 tbsp of sugar, using the fork. Add 1 qt. of water to the mixture.
Press a sheet of tin foil onto the Pyrex bowl to protect the contents. Add 1 cup of water to the pressure cooker. Put the bowl of agar mixture into the pressure cooker and assemble the lid. Cook on medium heat for 20 minutes at 15 psi. Start the timer when the pressure cooker reaches 15 psi. Allow the pressure cooker to cool for an hour before opening.
Arrange clean tuna and soup cans in a row as they will hold the test tubes at an angle. Pour the agar mixture into the measuring cup and fill the test tubes one-third full with the agar mixture. Apply caps loosely or use foil to cover the ends of the test tubes. Place three filled test tubes in each soup can. Add 1 cup of water to the pressure cooker. Place the cans with the test tubes into the pressure cooker, then secure the lid.
Sterilise the test tubes in the pressure cooker at 15 psi for 25 minutes. Start the timer when the pressure cooker reaches 15 psi. Allow the pressure cooker to cool on the hob for an hour.
Open the pressure cooker and remove the hot test tubes carefully, using oven gloves and place three test tubes in each tuna can to hold them at the correct slant to cool. Tighten the caps after the agar has cooled and turned into a gel. Cover each can of test tubes with tin foil to keep out dust.
Spray the kitchen counter with bleach diluted in water and wipe with paper towels. Work in the morning to avoid a draft and airborne dust. Work fast for the remaining steps.
Arrange the test tubes on the clean table along with the X-acto knife, mushrooms, lighted alcohol lamp and the fourth tin can that will be used to hold the flame-sterilised X-acto knife blade near the flame of the alcohol lamp.
Open a test tube carefully and place it between the middle and ring finger of your left hand if you are right-handed. Hold the cap between your pinky and ring finger.
Break the mushroom in half and do not let the cut side touch the table. Place the X-acto knife blade into the flame, then cut a small piece of the inside mushroom flesh and place it into the test tube. Replace the cap quickly and place the test tube with the newly created tissue culture back with the rest. Keep the X-acto knife blade near the flame when not in use. Repeat for the eight remaining test tubes.
Place masking tape around the bottom of the lid and record the date and variety on it, using the Sharpie marker. Keep prepared test tubes in a dark room at temperatures between 12.8 and 21.1 degrees Celsius for mycelia to grow.
Before using, sanitise the measuring cup, knife and fork in a dishwasher. A sanitised work area and instruments will reduce contamination from other types of spores. To avoid contamination, do not allow the cut side of the mushroom to touch anything but the flamed X-acto knife blade and the test tube
Always allow the pressure cooker to cool slowly to avoid foaming agar solutions. Do not work on a windy day as airborne spores can contaminate the tissue culture. Work fast when cutting mushroom tissue, or airborne contaminants can ruin a culture.
Tips and warnings
- Before using, sanitise the measuring cup, knife and fork in a dishwasher. A sanitised work area and instruments will reduce contamination from other types of spores.
- To avoid contamination, do not allow the cut side of the mushroom to touch anything but the flamed X-acto knife blade and the test tube
- Always allow the pressure cooker to cool slowly to avoid foaming agar solutions.
- Do not work on a windy day as airborne spores can contaminate the tissue culture.
- Work fast when cutting mushroom tissue, or airborne contaminants can ruin a culture.
- Penn State University Mushroom Spawn Laboratory: Seeding Substrate and Management of the Vegetative Stage of Growing the Commercial Mushroom, Agaricus Bisporus
- "Mykoweb": Getting Started With Mushroom Cultivation, Terri Marie Beauséjour
- Some Mushroom Growing Basics for Beginners: Randall R. Wayne, Ph.D.
- Penn State College of Agricultural Sciences: Mushroom Science and Technology