In the horticulture industry, there are a limited number of ways in which to properly maintain a plant population for an extended period of time. the means by which you do so will depend upon a number of variables for which you must account for in your grow operations. These variables include, but are not limited to, the amount of uniformity you are looking for from each crop, how much uniformity you are looking for from one generation to the next, whether or not you are searching for a way to improve an existing crop, and an innumerable amount of other goals which can be achieved through specific propagation methods. The primary methods for accomplishing these tasks through propagation are seed, cloning, and more recently, sterile tissue culture. Each one of these has situations in which one is more advantageous that the others, and by understanding the advantages and difficulties, as well as the steps behind each one, you will be able to make informed decisions on which method is most beneficial to your goals. When growing from seed, there are a number of different factors which must be taken into consideration. First, the seeds will not be identical genetically. This means that you cannot rely on them to provide you with a consistently uniform crop. this is also the propagation method which allows for a plant variety to be improved through breeding. Another benefit of seed is that the genetics can be preserved through seed with minimal care for much longer periods of time than woth cloning or sterile tissue culture. Also, seed is more easily transported from grower to grower, allowing for the sharing of superior genetics over greater distances than other propagation methods. Seed is also generally a little more simple to get started than clones are, and drastically more simple to propagate than from tissue cultures. The process of growing out a plant from seed varies from plant to plant. Some seeds germinate better after a period of refrigeration to simulate winter. Others do better when the hard outer coating of the seed has been scored or scratched, which allows the moisture to penetrate the coat and begin the enzymatic processes which will allow the young plantlet to begin growing. Some seeds will do even better when allowed to germinate before planting. The basic process for planting seed in the most simple of the three propagation methods we will discuss here. it entails placing the seed into a finely ground planting mix to cover it from direct sun and also to encourage growth. this mix must be kept well drained and evenly moist to allow the seed to flourish, but seedlings are at their weakest points when new, and overwatering can lead to a number of diseases and insects such as pythium, dampening off, and fungus gnats. The first method of asexual plant reproduction that we will look at is the process of cutting propagation, or cloning. this process entails removing a growing plant section, whether it be a tip, a section, or even a division of the roots or rhizomes in some plants, and you then use this plant section to replicate a genetically identical copy of your original plant. This process has huge benefits to orticulturists who are seeking to maintain a perfectly uniform crop. A uniform crop will produce a uniform product, maintain uniform growth characteristics, and most importantly, respond identically to environmental factors from plant to plant and from generation to generation. Cloning allows us to keep specific genetics intact for multiple generations, making planning a grow season more predictable from year to year. Just imagine if, every year, you had to grow an entirely new batch of plants and you have no understanding of their traits!This process can be as simple as ripping chunks off of your creeping sedum and throwing them in the dirt in other locations and watch them begin to root. It can be as easy as dividing your irises, or separating your runners from your strawberries. or, it can be as tedious as carefully making your cut underwater to prevent embolisms, cutting down into the Cambium layer to ease new root formation, dipping them in root hormone, and finally sliding your cannabis tip cuttings into their jiffy cubes and setting them under a humidity dome on a heating pad. Plant propagation by this method varies greatly not only in method, but also in ease and/or practice. Sterile tissue culture, or STC, is considered by some to be a more advanced process of cloning, and in some respects, this can in fact be considered the case. the process of STC still produces a genetically identical copy if the donor or "mother" plant, with all of the previously explained benefits that entails, but this is where the similarity ends and the benefits of STC become more apparent. STC involves taking as little as one cell from a plant, sterilizing it, placing it into a sterile container onto an ager with various hormones in it, capping the container with a gas-permeable lid, and alowing it to grow and differientate into new little plantlets. This procedure relies on the fact that each plant cell has the genetic knowledge contained within it to become any cell on the plant. A number of benefits that cloning cannot provide come up when using this new method, and while it may be much more difficult to master than the average cloning process (working sterile is a difficult process that requires DILIGENT attention to detail), it can be well worth the added benefits of the results. These may include the ability to save plants which are normally not salvageable through cloning. Pests and diseases spread from mother plant to clone and can sometimes seem as if they are impossible to get rid of. This sterilization process involved with STC allows the horticulturist to save even plants with viral diseases such as the Tobacco Mosiac Virus. STC's are much more portable than clones, allowing for easier transport of genetics. They also allow for a massive genetic collection to be stored in a relatively small space, with the STC plantlets being nursed in jars no bigger than a baby food jar, and they can be then kept on shelves under fluorescent lighting. The benefits of each propagation method must be taken into consideration when deciding on your propagation method or route. With seed generally being the most maintenance free, cloning being slightly more difficult, and STC being scientifically tedious in the extreme, it becomes the responsibility of the horticulturist to determine the end goals which aim to be accomplished with the grow, and then decide which method most suits their needs.
