One of the most important factor in cannabis cultivation is selecting the best genetics . This is done by selecting one or more known strains, or strains with preferred genetics, in the case of marijuana, one might use seeds from a batch that was particularly enjoyed, or buy selected clones from known friends and then growing a number of the seeds or clones to find out which exhibit the characteristics most desirable to the cultivator.
Plant characteristics which are generally selected for include:
Overall yield
Flavor and aroma
Flowering time
Resistance against heat in de summer
Resistance against cold in de winter
Resistance to mold
Resistance to spint, white fly, trips, scale insects, etc
THC level
Easy clone plant
Grow speed
Ploidy , diploid 20 chromosomes, tetraploide 40 chromosomes or octaploide 80 chromosomes
Geometric traits like uniformity, compactness, flower density, etc
Color
Psychoactive qualities like "how you feeling after smoking your weed"
Trichome density and type, stalked or sessile
Price to the buyer and appeal to end buyer, how it looks, smells, taste and feeling
When a cultivator has decided which plant or plants exhibit the most desirable traits, a cutting is taken and grown but never allowed to flower, 16 to 18 hours light a day.
This plant is referred to as a motherplant, and can be kept for many years, producing thousands of clones genetically identical to the mother or feminized seeds.