Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

preserve potency, than selecting the most potent of the early plants. It really depends on what traits the breeder ranks in importance to the program, a decision based on the breeding goal.
    Usually, varieties that perform well under artificial lights will also perform well outside or in a glass house under natural sunlight after two or three years of acclimation. The converse doesn’t hold true nearly as often. Varieties that perform well outside, especially pure sativa varieties, often prove disappointing when grown under artificial light.
    Post-harvest selection requires either partial seeding of each plant (only seeds from themost potent plants are sown for successive generations) or keeping clone copies of each and every plant, for future seed production use once post harvest evaluations are done.
    5 - Commercialize.
    This is an optional part of a breeding program. Some people breed to create a variety that suits their specific growing environment and smoking tastes, without ever intending to profit from the sale of their work. They just want reliable seeds for their own planting and future use. Some are of the opposite extreme; they make seeds exclusively to sell. These “breeders” do very little breeding. We refer to them as seed makers.
    Because cannabis is a species under attack from various governments and other evil forces around the world, true breeders with goals and intentions other than financial are sorely needed to protect the genetic resources cannabis has left. Years of persecution from governments and greedy seed-making practices without improvement or preservation have led to a genetic bottleneck, a narrowing of the potentially available breeding stock. Now more than ever, ethical breeding should be of utmost concern to cannabis enthusiasts. The species desperately needs breeders who are willing to improve populations in their possession, all the while preserving valuable genetic resources for future generations of breeders.
    Sam the Skunkman, a great ally of cannabis, says we all stand on the shoulders of those who have come before us. We can build upon the improvements our ancestors have made to landraces and wild populations, but we can only work with what they have left us. Selections and advancements come at a cost to genetic variability. Breeders often reduce variability by narrowing the gene pool of that particular population as a consequence of fixing traits. The best breeders strive to advance and improve a given variety or population while preserving the variation present for the traits not under selection, which may prove valuable for future breeders and growers.

Growing out a large number of seedlings is the best way to find a good mother plant

You can find just about any marijuana seed you can imagine on the market today.
Types of Seed Populations
    Inbred Line/Pure Line
    Some refer to these as IBLs. An inbred line is a seedlot that has been bred for generations while
    selecting repeatedly for specific traits, to the point where the population reliably reproduces the traits under selection in each successive generation of breeding. These plants are said to breed true for these characteristics. There is little or no variation for these traits, which are thus considered pure. Pure lines make the best breeding stock as the progeny of crosses using known pure parental lines have a predictable outcome in subsequent generations. Inbred lines are uniform in growth patterns and traits and are stable genetically-each generation of inbred seed results in plants similar in most ways to the previous generation. Pure lines are homozygous at most alleles.
Hybrids
    Hybrids are a product of a cross between genetically unlike parents. Hybrids retain their distinctive characters if reproduced asexually but fail to reproduce these characters completely or reliably when reproduced sexually. Hybrid cultivars are developed by using available inbred lines or creating new ones from segregating populations, and then coupling selection with inbreeding for homozygosity, evaluation of inbreds for combining ability in hybrid combinations, and subsequent multiplication of selected inbred lines for hybrid seed production.
There are various types of hybrid varieties:
    F1 hybrids (‘Northern Lights’ × ‘Blueberry’, ‘Northern Lights’ × ‘Haze’, ‘Frostbite’)
    3-way crosses (‘Skunk #1’ - a cross of (Mexican × Columbian) × Afghani)
    Double cross hybrids (a cross of 2 unrelated F1 hybrids