There are many types of breeding programs, some more complex than others (click here to learn more about Breeding Programs). The type of breeding method you use depends fully upon what you are wanting your outcome to be. Ideally, potential breeders understand the benefits and drawbacks of each strategy before they take action. It is often that breeders will use more than one method to achieve their goal. Some often-used measures of performance are General Combining Ability (GCA) and Specific Combining Ability (SCA). General combining ability is the average or overall performance of a given line in hybrid mixes open-pollinated with other lines. Open pollination is a very low effort type of seed production and involves minimal selection to no selection. The seeds are planted and left to flower so the plants are then gone through as well as undesired ones are removed. Inbred lines and other populations are maintained through open pollination and are often bred by a single person then produced for commercial production and sales by other people. There are some breeders who create their own true-breeding population then license out the seeds to companies, who in turn plant them and create more for sale. This is called a seed-increase. Inbreeding is simply crossing a variety of plants within themselves with no additions of genetic material. The most severe form of inbreeding is the self-cross where the plant pollinates itself. When two (2) individual plants are crossed again and again in such a tight as well as narrow breeding population, this leads to a condition that is known as “inbreeding depression”. Cross pollinated crops will exhibit a higher degree of inbreeding depression if it is through self-crossing. In cross-pollinated crops, negative attributes can be revealed or unmasked within the populations though continual inbreeding. Inbreeding depression can be apparent within Self-1 or S1 populations after a single generation of self-fertilization. When you are breeding cannabis in a small population, it is often the case with repeated 1:1 breeding schemes and inbreeding depression sets in around the third (3rd) to sixth (6th) generation. To solve this, issue a breeder will commonly maintain a separate, parallel breeding line where each of which are selected for similar or identical traits that they express. After many generations of inbreeding when each of the inbred lines or selfed populations begin to show inbreeding depression. This is because they are crossbred to each other to restore the plants robustness and eliminate inbreeding depression while preserving the genetic constancy of their traits under selection.
Cannabis is naturally an out-crossing or cross-pollinating species and existed in the wild breeding populations of hundreds if not thousands of individuals. Among all of these individuals, there lies a wide array of genes. When only one (1) or two (2) plants are selected for breeding, we radically decrease the genetic variability found in the original population, basically creating a genetic bottle neck of sorts. With this the inconsistency is lost from populations and becomes inaccessible for future generations.
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Variety is a subdivision of kind, group or family that is distinct in some characteristics. All plants will show a common set of morphological, physiological and other characteristics that are different from other varieties (click here to learn about Marijuana Genetics). The variety must be constant and they will remain unaltered, within reason of their characteristics, when they are reproduced. Cultivar is a term derived from ‘cultivated variety,’ a population of cultivated plants that are clearly distinguished by specific characteristics. All plants will show a common set of morphological, physiological and other characteristics so when they are reproduced, either sexually or asexually, they will still retain their distinctive characteristics. Strain is not a scientific botanical term, though seeds sold are nothing more than hybrids of hybrids and referred to as strains. Strain is a general term that is applied to selections of cultivars or varieties. Open pollinated varieties are non-hybrid populations that are reproduced by random pollination. Whether in outdoor gardens or indoor gardens, pollen is carried with the breeze and pollinates female plants. Open pollinated varieties are developed through many years of selective planting and seed saving, varieties are non-hybrid. Heirloom varieties are nothing more than a variety that was liked for what it was and kept and handed down for generations. Heirloom varieties are non-hybrid (open-pollinated) which means that they breed relatively true and every year they are very similar to the generation before. Multi-line is two or more pure breeding lines that differ in a small part of the overall phenotype (maturation, disease and pest resistance, etc).
These are grown and bred separately, but end up being mixed together in the same seed package. These work well for new growers or growers who are unsure if a certain variety will work for their area with the climate, as well as provide a variety. Let us know what you think. (Click Here To Learn More About How To Become A Budtender) [Ed. Note. Green CulturED has created an intuitively designed educational experience that is delivered in the way students learn and interact online today. It is their commitment to increase the number of states with medical marijuana laws, supporting and improving existing state medical marijuana programs, protecting medical marijuana patients, and ending the federal ban on medical marijuana. Click here to start learning about this emerging industry today.] |
authorLilly, the gardener. Archives
September 2019
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