Propa ga tion
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Figure 3.7: Tissue culture set up for producing plants aseptically.
After a period of time the microscopic section of plant will grow. Eventually it can be moved (via a series of stages) into the outside environment. Tissue culture is of increasing importance in the nursery industry. Its commercial potential has rapidly developed over the last two decades, and now many plants sold in nurseries are propagated using this technique. Some plants are much easier to produce by tissue culture than others. The main advantages of tissue culture are: • propagation of difficult species. Some things which have proven extremely difficult to grow other ways have been grown in large quantities via tissue culture; • plants can be propagated at any time of the year using tissue culture techniques; • the ability to propagate rapidly. If a new hybrid has been developed, it can take several years to produce enough individual plants of that hybrid to make it worthwhile marketing it. Using tissue culture it is possible to produce tens of thousands of specimens of the new hybrid within a year. In woody species, breeding and selection by sexual hybridisation has been slow because of the long periods of time between each generation. Tissue culture can speed this process considerably; • considerable savings in time and space compared with those required by conventional procedures; • disease-tested material can be bulked in large quantities without the costly precautions that are otherwise needed to prevent reinfection during propagation. Plants such as lilies, strawberries and potatoes, while not necessarily difficult to propagate conventionally, are very susceptible to viruses.