The Cannabis Breeder's Bible (35 page)

Curing and Manicuring

Before curing begins we need to manicure our bud and after we have cured our bud we may further manicure it. Manicuring includes the separation of the leaf and the branch material from the stem while leaving the flowering clusters attached. The calyx to leaf ratio is important here because plants that have a higher calyx to leaf ratio require less manicuring per flowering cluster. If a plant has a 1:1 calyx/leaf ratio then there is at least one leaf per calyx to clip off, while a 5:1 would mean there is only one leaf per 5 calyxes to manicure. Also leaf size and petiole length are important here. It is far easier to remove larger leaves on long petioles than it is to remove smaller ones on short petioles. However, smaller leaves allow light to penetrate more bud regions underneath and generally shorter petioles of the leaves on the flowering clusters can develop lots of trichomes at the base of the leaf. To make manicuring easier and more rewarding, try to develop a strain with a higher calyx to leaf ratio.

Curing is the length of time it takes for your bud to dry properly, which is generally between one to four weeks. You may find that some strains cure better and quicker than other strains grown under similar conditions. This has to do with a combination of the following factors.

• cannabinoid content.

• bud density.

We will look at these factors later on. “Bag seed”
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is a term used to describe seed that is found in street weed. Street weed tends to come from countries or growers that like a quick turnover in their produce and so their plants are bred for quicker drying and curing processes, not to mention ease of manicuring. Bag seed tends to have the following problems:

• hermaphrodite

• not very potent

• lacks resin content

• lacks flavor

• non-uniform in growth

• bred for outdoor performance only

• lacks vigor

• lacks quantity

But most bag seed does have the shortest curing times (the cultivators want a quick turnover), not to mention resistance to disease and pests. However the hermaphrodite nature of the plant makes it absolutely dangerous to include in any breeding project. This is very dependent on where the bag seed came from. If it came from an excellent specimen then the strain might be very good.

Different domesticated landrace strains from various countries cure better and quicker than others. Through experimentation you will be able to find strains that have different rates of curing. Most Indica and Sativa strains on the market today have a curing time between three and eight weeks. (For full information on harvesting and curing, see chapter 14 of
The Cannabis Grow Bible.)

A spider mite pest attack has caused this plant to develop dark hues and unhealthy leaves. Photograph by Kissie.

Disease Resistance (Including Pests)

By taking any population of plants and infecting them with a disease you may find that a good percentage of the plants fail while others can live through the crisis. By applying the ‘Survival of the Fittest’ from the theory of evolution we can select offspring that we think have resistance to specific diseases and pests. We can run cross tests to see if we can breed the trait true and thus create a population of plants that are good at fighting disease and pests. The more different diseases and pests we introduce to the resistant population the better our chances of creating a strain that is hardy in these conditions.

There are two ways that a plant can deal with pest attacks and disease:

• prevention

• recovery

How well plants deal with these is called resistance. Resistance does not mean that the plant can recover well or prevent further attacks. Resistance is the length of time that a plant can survive an attack and complete the grow cycle. Low resistance would mean that the plant failed to regenerate itself quickly (basically not replacing damage at a faster rate than that at which the damage is occurring) or live through the attack. Plants with a strong resistance to pest and disease attacks can help a grower who is nearing harvest time but has a pest/disease problem to deal with. If the plant is able to resist the attack it may complete its maturation and thus be harvested. Plants that have a low resistance to pest and disease attacks may fail before floral maturity is complete. In many growers’ eyes it is better to have something at the end of harvest rather than nothing all. A plant may have a low resistance to an attack and the attack effects plant health and the final yields but at least it produces something rather than failing completely. Just because the plant is growing in less than optimal conditions because of a pest attack should not mean that the plant fails altogether. Breeders should try and adopt some resistance to common pest and disease attacks with their strains, especially if creating a strain for the outdoor market.

There are many different pests and diseases to deal with, but a very common pest attack problem such as spider mite infestation (which can reduce a plant to trash in a couple of days), might be a useful one to try for our breeding resistance project. By introducing spider mites to a crop at flowering time we will find out which plants last longer than others.

A single grasshopper causes no harm, but in greater numbers they can quickly do massive damage to a crop.

Prevention involves a defense against pest attack. Resin and smell are both associated with pest defense. Some smells can attract unwanted pests while other smells will repel certain pests. We may notice that in a flowering crop of hybrid plants, pests are attracted to some of the hybrids and not others. The ones that are left alone may have a smell or an aroma that repels the pests.
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Resin also helps to prevent insect attack because some insects find resin too sticky to inhabit. Also the insect may find the cannabinoid content of the resin unpleasant.

Recovery is the plant’s ability to regenerate itself during and/or after a pest/disease attack. Some plants can recover more quickly than others. If leaves are removed because of pest/disease destruction then new leaves might be generated just as quickly.

Locusts are a very interesting pest because in small numbers they will not harm a plant very much. They may spend a few days working on one leaf or remove a number of leaves over a long period of time. The plants can deal with this and regenerate new leaves very quickly. But a swarm of locusts can reduce the plant to just stems, roots and branches in a few hours. There is a threshold level at which the plant can reproduce leaves as quickly as they have been removed. The stress, coupled with lack of energy (no leaves = no photosynthesis = no energy) can kill a plant quickly.

Mold and fungi can also be tested on strains that you want to breed resistance into. Mold and fungi thrive in hot, humid and aged air conditions. Fresh air in the open deals well with aged air problems but indoor grows may suffer from heat, humidity and air-conditioning problems and thus be more susceptible to mold and fungi. This also helps to curb mold problems in the curing process.

Floral Traits This is such a large topic that we will deal with it separately in the following chapter.

Leaf Traits

Most pure species have very obvious leaf traits such as the low blade number/broad stubby Indica leaf trait and the high blade number/long thin Sativa leaf trait. These are the first elements of plant species identification that a breeder would look out for when determining the species type of a strain.

Observation of height, internodes, branching, flowering times and high type would also help in deducing the species type. Once you have seen the pure species types you will be able to identify other different pure species types again elsewhere. Cross species such as Mostly Indica or Mostly Sativa or Indica/Sativa can have leaves different from the traditional pure species leaf trait. Indica tends to be darker than Sativa but some Indica/Sativa crosses can result in dark Sativa leaves or pale Indica leaves. Sativa leaves can have anywhere between five and twelve blades on each leaf while Indica leaves do not usually go above six or seven. Cross-species types can produce Indica leaves with more than six blades per leaf and Sativa strains can be bred to produce five blades or less.

Leaf traits: Pure Indica, Mostly Indica, Indica/Sativa, Mostly Sativa and Pure Sativa.

There has been a lot of debate as to whether or not some leaf shapes can be passed down to future offspring. This is because cannabis observation in the past has uncovered some very strange leaf patterns and shapes produced through cross-species breeding projects. Most of the observations have been attributed to environmental factors influencing phenotypes, while other strange anomalies are thought to be the result of a mutation. (Remember the single-bladed leaf produced by some clones we discussed in chapter 17)

Environmental factors heavily influence the phenotype of cannabis leaves and sometimes it is hard, even under optimal growing conditions, to keep a plant’s leaf trait very uniform. Some Mostly Indica species cannot help producing very dominant Sativa-shaped leaves around the top colas or even fan-type leaves very close to the top of the plant.

Whenever there is competition a healthy strong plant will try and outgrow the others to receive more light, producing strange leaf shapes and traits. A clone may produce single blade leaves for a couple of weeks in order to receive as much light as possible and sustain itself. This again amplifies the necessity of understanding that
the genotype is expressed in the phenotype, which is under the influence of the environment.

When breeding for leaf traits it is best to observe the population very carefully and note the patterns of leaf growth and shape on every branch. You are trying to achieve uniformity but not at the expense of other characteristics. Because the leaf is the plant’s primary tool for energy gathering it must be treated with extreme importance but never manipulated to the extent that it causes the plant to perform weakly in its intended environment. A large plant can survive with many thin Sativa leaves but never with only a few average sized or even large Indica-type leaves.

A healthy cannabis plant develops lateral branches with outstretched leaves that look as if they are enjoying the light, not too bushy, not too sparse, but even in distribution for optimal performance.