material, while others may produce more seeds or exhibit a greater degree of immunity, resulting in a greater number of offspring surviving to contribute genetic material to the population.
HOW TO TRUE BREED A STRAIN
Breeding cannabis strains is all about manipulating gene frequencies. Most strains sold by reputable breeders through seed banks are very uniform in growth. This means that the breeder has attempted to lock certain genes down so that the genotypes of those traits are homozygous.
Imagine that a breeder has two strains: Master Kush and Silver Haze. The breeder lists a few traits that he particularly likes (denoted by *).
MASTER KUSH
SILVER HAZE
Dark-green leaf
Pale-green leaf *
Hashy smell *
Fruity smell
White flowers
Silver flowers *
Short plants *
Tall plants
This means he wants to create a plant that is homozygous for the following traits and call it something like Silver Kush.
SILVER KUSH
Pale-green leaf
Hashy smell
Silver flowers
Short plants
All the genetics needed are contained in the gene pools for Master Kush and Silver Haze. The breeder could simply mix both populations and hope for the best or try to save time, space and money by calculating the genotype for each trait and using the results to create an IBL.
The first thing the breeder must do is to understand the genotype of each trait that will be featured in the ideal “Silver Kush” strain. In order to do this the genotype of each parent strain for that same trait must be understood. Since there are four traits that the breeder is trying to isolate, and 4 × 2 = 8, eight alleles make up the genotypes for these phenotype expressions and must be made known to the breeder.
Let’s take the pale-green leaf of the Silver Haze for starters. The breeder will grow out as many Silver Haze plants as possible, noting if any plants in the population display other leaf colors. If they do not, the breeder can assume that the trait is either homozygous dominant (SS) or recessive (ss). If other leaf colors appear within the population, the breeder must assume that the trait is heterozygous (Ss) and must be locked down through selective breeding. Let’s look closely at the parents for a moment.
S
SS
S
SS
SS
S
SS
SS
If both parents were SS there wouldn’t be any variation in the population for this trait. It would already be locked-down and would always breed true without any variations.
S
s
S
SS
Ss
S
SS
Ss
With one SS parent and one Ss parent, the breeder would produce a 50:50 population—one group being homozygous (SS) and the other heterozygous (Ss).
S
s
S
SS
Ss
s
Ss
ss
If both parents were Ss, the breeder would have 25% SS, 50% Ss and 25% ss. Even though gene frequencies can be predicted, the breeder will not know with certainty whether the pale-green leaf trait is dominant or recessive until he performs a test cross. By running several test crosses the breeder can isolate the plant that is either SS or ss and eliminate any Ss from the group. Once the genotype has been isolated and the population reduced to contain only plants with the same genotype, the breeding program can begin in earnest. Remember that the success of any cannabis breeding program hinges on the breeder maintaining accurate records about parent plants and their descendents so that he can control gene frequencies.
Let’s say that you run a seed bank company called PALE-GREEN LEAF ONLY BUT EVERYTHING ELSE IS NOT UNIFORM LTD. The seeds that you create will all breed pale-green leaves and the customer will be happy. In reality, customers want the exact same plant that won the Cannabis Cup last year or at least something very close. So in reality, you will have to isolate all the ‘winning’ traits before customers will be satisfied with what they’re buying.
The number of tests it takes to know any given genotype isn’t certain. You may have to use a wide selection of plants to achieve the goal, but nevertheless it is still achievable. The
HOW TO TRUE BREED A STRAIN
Breeding cannabis strains is all about manipulating gene frequencies. Most strains sold by reputable breeders through seed banks are very uniform in growth. This means that the breeder has attempted to lock certain genes down so that the genotypes of those traits are homozygous.
Imagine that a breeder has two strains: Master Kush and Silver Haze. The breeder lists a few traits that he particularly likes (denoted by *).
MASTER KUSH
SILVER HAZE
Dark-green leaf
Pale-green leaf *
Hashy smell *
Fruity smell
White flowers
Silver flowers *
Short plants *
Tall plants
This means he wants to create a plant that is homozygous for the following traits and call it something like Silver Kush.
SILVER KUSH
Pale-green leaf
Hashy smell
Silver flowers
Short plants
All the genetics needed are contained in the gene pools for Master Kush and Silver Haze. The breeder could simply mix both populations and hope for the best or try to save time, space and money by calculating the genotype for each trait and using the results to create an IBL.
The first thing the breeder must do is to understand the genotype of each trait that will be featured in the ideal “Silver Kush” strain. In order to do this the genotype of each parent strain for that same trait must be understood. Since there are four traits that the breeder is trying to isolate, and 4 × 2 = 8, eight alleles make up the genotypes for these phenotype expressions and must be made known to the breeder.
Let’s take the pale-green leaf of the Silver Haze for starters. The breeder will grow out as many Silver Haze plants as possible, noting if any plants in the population display other leaf colors. If they do not, the breeder can assume that the trait is either homozygous dominant (SS) or recessive (ss). If other leaf colors appear within the population, the breeder must assume that the trait is heterozygous (Ss) and must be locked down through selective breeding. Let’s look closely at the parents for a moment.
S
SS
S
SS
SS
S
SS
SS
If both parents were SS there wouldn’t be any variation in the population for this trait. It would already be locked-down and would always breed true without any variations.
S
s
S
SS
Ss
S
SS
Ss
With one SS parent and one Ss parent, the breeder would produce a 50:50 population—one group being homozygous (SS) and the other heterozygous (Ss).
S
s
S
SS
Ss
s
Ss
ss
If both parents were Ss, the breeder would have 25% SS, 50% Ss and 25% ss. Even though gene frequencies can be predicted, the breeder will not know with certainty whether the pale-green leaf trait is dominant or recessive until he performs a test cross. By running several test crosses the breeder can isolate the plant that is either SS or ss and eliminate any Ss from the group. Once the genotype has been isolated and the population reduced to contain only plants with the same genotype, the breeding program can begin in earnest. Remember that the success of any cannabis breeding program hinges on the breeder maintaining accurate records about parent plants and their descendents so that he can control gene frequencies.
Let’s say that you run a seed bank company called PALE-GREEN LEAF ONLY BUT EVERYTHING ELSE IS NOT UNIFORM LTD. The seeds that you create will all breed pale-green leaves and the customer will be happy. In reality, customers want the exact same plant that won the Cannabis Cup last year or at least something very close. So in reality, you will have to isolate all the ‘winning’ traits before customers will be satisfied with what they’re buying.
The number of tests it takes to know any given genotype isn’t certain. You may have to use a wide selection of plants to achieve the goal, but nevertheless it is still achievable. The
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