An important factor in cannabis cultivation is selecting the best genetics for one's crop. This is frequently 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), and then growing a number of the seeds to find out which exhibit the characteristics most desirable to the cultivator. These genetics should typically yield at least 1 gram per watt. Plant characteristics which are generally selected for include: * Overall yield * Time to fruition * Resistance to pests * Geometric traits (uniformity, compactness, flower density, etc) * Color * Flavor and/or aroma * Appeal to end buyer (known as "bag appeal") * Psychoactive qualities * Trichome density and type (stalked or sessile) When a cultivator has decided which plant or plants exhibit the most desirable traits, a cutting is taken and grown to maturity but never allowed to flower. This plant is referred to as a mother, and can be kept for years, producing thousands of clones genetically identical to the mother.[30] [edit] Feminized seeds It is possible to use a combination of cloning and "shocking" plants to get them to produce feminized seeds.[31] A clone will retain the same sex throughout its life, so if a female plant is cloned, its clones will also be female, precluding reproduction. Some claim (particularly vendors of feminized seeds produced with certain methods) that while environmental stresses have been used to create pollen bearing male flowers on female plants- known as 'hermaphroditing' or 'hermying', this method is not preferred when creating feminized seeds; due to those plants most likely to revert to seed making being the ones which hermie soonest; hence passing on the genetic trait of instability of gender - desirable in the wild but not in cultivation. Spraying selected leaves, branches and in cases where large amount of seed desired whole plants with colloidal silver solution has become a preferred method since the colloidal silver suppresses ethylene production in bud sites, stimulating male characteristics. Gibberellic acid has been used frequently; but is harder to find than colloidal silver, which involves nothing more than a small wall d.c. power supply and two pieces of solid silver jeweler's wire, or 99.999% silver coin. A method used by organic growers and promulgated by the famous Cannabis breeder Soma, is called 'Rodelization', or letting unpollenated female plants live several weeks longer than the normal harvest time. In such plants a hermaphroditic trait will self express in effort to continue the genetic line; the fact this method utilizes auto hermaphroditic traits which could contribute to instability in a plant's genetics is offset by grower observations that the tendency to auto-switch sex is not great in plants grown from seeds made this way, and the fact that it occurs naturally without effort on the part of the cultivator. However, other cultivators claim that the genes responsible for hermaphroditism are present and may be activated under stress from any of the above methods and that once activated can be passed to seeds regardless of how it was activated. Previous theories would not have allowed for the passing of genetic alterations an adult has acquired after birth but there is evidence that when a gene is activated in a mother after her birth that expression can be passed to offspring.[