The Cannabis Breeder's Bible (32 page)

Note that there are two very distinct types of hermaphrodites. Permanent hermaphrodites are capable of producing both ova and spermatozoa at the same time, while ‘Protandrous hermaphrodites’ male gametes mature and are shed before female gametes mature. As you can guess the combinations that can lead to dioecious development are many. Each has its own scenario that can be played out and, more importantly, reversed. This can lead to a breakthrough in creating dioecious strains from strains that have hermaphrodite problems! Breeders take note of this and remember the various sexual reversal experiments.

The aim of this chapter has been to explain a bit about the ‘evolutionary conduit’, or the evolutionary development, of the dioecious plant and the outcome of inbreeding depression. Each is relative to our growing environment. Since most of us want uniform plants for growing reasons, we are looking for inbred lines even though the line will be depressed. We are also looking for dioecious plants because we want a sinsemilla crop and if we want to add a genetic boost to our crop we should take advantage of hybrid vigor. On top of this we have covered the more advanced aspects of understanding cannabis gender types, how the genders evolved in cannabis and how it can be manipulated by the breeder. It is wise to try and keep all cannabis sex reversal experimentations away from contaminating the gene pool. You can however experiment on your own models to see if you can eliminate hermaphrodites from a known hermie population. This is a very good breeding project to try out especially with high yielding and potent hermaphrodite strains that nobody wants to work with because they can never produce a sinsemilla crop with it.

18

MORPHOLOGY AND BREEDING TRAITS

AN INTRODUCTION TO CANNABIS PLANT MORPHOLOGY

“Cannabis plant morphology” is about the cannabis species as a whole and the various strains’ relationships with one another. “Plant morphology” is a wider area of study focused on the relationships between different plant families, orders and classes. We will be dealing only with cannabis plant morphology here, relative to the topic of cannabis breeding. There are two major sections of cannabis morphology: cannabis vegetative characteristics and cannabis floral characteristics.

Cannabis Vegetative Characteristics

There are a few types of obvious vegetative characteristics that we need to look at. These are: leaf and branch arrangements, leaf shapes, leaf types, leaf venation, roots, stem habits and buds (not flowering bud, but vegetative buds).

Basic Structure

Cannabis is an erect plant with tough bast fibers. It grows upward and sideways. Side branching has a tendency to curve upward although this may not be apparent during the latter stages of flowering growth because of flowering weight on these branches. During germination of the plant, cannabis also has a straight
hypocotyl
(embryonic stem). The
cotyledons
(the seedling’s first set of leaves) appear single-bladed and close to one another. As the seedling grows it develops petioles, branches and more leaves. After a few weeks it begins to look more like a cannabis plant.

Leaf/Branch Arrangements

The leaf/branch arrangement for cannabis is known as an “opposite” arrangement (decussate) because branching develops in pairs at the same levels on the stem or branch. If more than a single pair of branches develops at the same level on the stem then, as discussed in chapter 17, the arrangement is referred to as a “whorled” arrangement. If the branches develop one above the other it is known as an “alternate (staggered)” arrangement.

Fundamental structure of the cannabis plant.

The cannabis leaf shape (Indica/Sativa hybrid).

A single cannabis plant can possess all of these arrangement types. Whorling is the rarest of the three. The alternate leaf/branch arrangement is the second most common type and usually occurs during flowering and/or after pruning; however it may also occur naturally without flowering or pruning

Leaf Shapes

Leaf shape is divided into the main leaf shape, the apices (narrowed or pointed end) and the base. The main leaf shape of the cannabis plant is “palmately-compound.” (having veins or leaflets arranged like the fingers on a hand). The apices of the leaf is of the “aristate” type because of the fine long point that it comes to at the top of each linear blade. The base of each blade is “acuminate” because of its uniform slender closure. In some strains this base is “acute,” in which case it comes to a very sharp close with a noticeable distance between the closure and opening out of the blade width. The leaflets are coarse-toothed which makes them “serrated.”

“Opposite and Alternate cannabis plant branching arrangements.

Cannabis blade shape and venation.

Leaf Venation

You would presume the palmately-compound leaf trait would indicate the palmately veined venation trait, but this is not so. Cannabis is in fact pinnatelyveined, That is, there is a main vein running from the base to the tip of each finger. Along each main vein are smaller veins that branch off in a somewhat even fashion to touch the sides of each blade.

Roots

The cannabis plant roots are the “Taproot.” type but are often short and stubby except for that of very large Sativa varieties that can grow a very long taproot. In general the taproot is poor in size and the plant depends largely on a more fibrous root system that branches from the taproot in many multiples. This fibrous route trait can also have “Prop root” properties where the roots that are very close to the soil’s surface act like supports for the plant. This can be seen in longflowering Sativa strains. The root type is classed as primary and cannabis roots grow most vigorously during vegetative growth and less so in flowering. If you transplant during vegetative growth you may notice with smaller strains of the Indica species type that the roots have reached the outer edge of the soil even in large three gallon containers. After harvest you may notice that the roots do not appear to have reached the outer edge of soil in the larger container they were transplanted into. This is because roots do the majority of their growing in the vegetative stage. It is more than possible to produce several gallons of a root mass from a single cannabis plant when growing in hydroponics systems.

Taproot of the cannabis plant.

Terminal bud zone.

Stem Habits

The stem habit is a straightforward “ascending” stem characteristic. The most other straightforward trait is that the stem is of the above ground type.

Buds (Node Buds Not Flowering Buds)

There are two types of buds found on the cannabis plant, separated only by their location. They are the “stalked/lateral” bud type which is found on the node points and the “terminal” bud, which we find only at the very head of a stem or at the head of a number of stems. The most impressive terminal bud location of the cannabis plant is the “top cola”.

All of these morphological elements are the cannabis plant’s core vegetative attributes and are the most common physical aspects of the plant that you will be working on during your breeding projects. Even though cannabis has a set template for each of these shapes you can still control how that shape is expressed in size, numbers, color, location and spacing to a certain degree. For example: cannabis plants express the palmately-compound leaf type but Sativa leaves are very different from Indica leaves in their size, numbers, color and spacing.

There can also be multiple expressions of each classification. While the roots are of the taproot category, they can also fall into the fibrous root category. Though they do not appear to grow from the stem, sometimes low down on a plant the roots can increase in size and break the surface, giving the appearance of being “adventitious” and growing from something other than root tissue.