[Aardwolf]

The particulars of breeding operations themselves in the modern world of plant-breeding plans differ between Genus's and Species's in various ways, depending on the purposes for which these different crops are grown and on their various attributes.

Nevertheless, many otherwise apparently quite unalike crops have particular attributes in common, especially mating system and or method of propagation, such that nearly all crops can be assigned explicitly to one of the three main groups in respect to the breeding plan that will be appropriate for each.


Group 1 - Primarily self-fertilizing, seed propagating annuals, & ephemerals; Wheat, Rice, Barley, Cannabis rudaralis and Phaselous beans

Group 2 - Out-crossing, seed propagated annuals (especially corn) Biennials, short-lives perennials and long-lived perennials, including many timber tree species.

Group 3 - Vegetatively (Clonally) propagable out-crossing perennials, many of which can also be propagated from seeds.

Seed propagation type describes how the selected plants in a retained family, from the previous selection round or generation, are propagated, to generate the seed for the current selection round or generation.

There are nine options for seed propagation, (F1 excluded): In order of increasing genetic diversity (i) clone (asexual reproduction), (ii) DH (doubled haploid), (iii) self (self-pollination), (iv) single cross (single cross between two parents), (v) backcross (back crossed to one of the two parents), (vi) topcross (crossed to a third parent, also known as three-way cross), (vii) doublecross (crossed between two F1s), (viii) random (random mating among the selected plants in a family), and (ix) no selfing (random mating but self-pollination is eliminated).

[Aardwolf]

It seems appropriate to start this broad conceptual overview of genetic principles on which plant breeding plans are based and perhaps the most basic concept of genetics and plant breeding, namely the relationship between genotype & phenotype.

Genotype and environment are jointly responsible for the phenotype ultimately realised by any breed.

Therefore the breeders goal is to produce superior phenotypes in the environments envisioned for the cultivation of his new improved variety, essentially showing Multi-environmental potential/Stability.

The Genus Cannabis has multiple measurements of various aspects of the phenotype (e.g., Yielding ability as well as other various components of quality)

(Collectively we could make a list here from multiple perspectives of all the components that make quality cannabis).. Disregard environment for the purposes of this list as traits should ideally be genotypical and thus always there.

1 Terpene Profile
2 Resin Content or percentage to bio-matter
3 Effects - Duration of High
4 Heterosis

Assessments must be made in multiple relevant environments to determine whether any genotype or group of similar genotype's that survive into the late stages of a breeding program, will be suitable both agriculturally and satisfying human needs. Furthermore as consumer preferences often change, breeders must be prepared to adjust their initial goals at short notice.

Before exploring the rules for guiding allelic substitutions, it seems appropriate to consider the terminology of expression for the alternative alleles that may be encountered at any single genetic locus.

First, any single locus can be known only to exist with any certainty only if at least two alleles with distinguishable phenotypical expressions have been shown by segregation tests to be responsible for the phenotypic expressions of the locus.

Second, an allele is said to be fully dominant when the phenotype from one homozygote a1a1 and the heterozygote a1a2 are indistinguishable from each other phenotypically.

Alleles are said to be Codominant when both are distinguishable in the heterozygote, Partially dominant when the heterozygote is intermediate between parental types, and Overdominant when the phenotype lies outside the range of one or the other parental types.

A number of additional points are important here, breeders are usually concerned with the leading effect of genes, an example; whether a specific allele leads to tall or short plants or to a superior verses inferior ability to survive in a given environment.

'The above is text curtsey of POPB (R.W Allard) https://books.google.co.uk/books?id=7...plants&f=false

There are a number of interesting factors behind these statements relating to Cannabis which are particularly relevant to the concerned learned breeder'.

He mentions breeders are therefore applied evolutionists, who choose apparently suitable parents, hybridize these parents in an attempt to develop populations containing seemingly desirable genotypoes using, suitable combinations of natural and artificial selection in guiding allelic substitutions towards hopefully realizable goals.

[Aardwolf]

The superior ability for plants to survive in a given environment is critical for people who wish to reproduce their particular variety of cannabis.

If we look at the ways in which cannabis is able to reproduce sexually we shall discover much about it's natural biology.

"The natural biology is the normal plant processes by which seed is propagated within the species without additional outside help".

Cannabis has 'pistillate individuals', 'staminate individuals' and then all manner of combinations of Plant reproductive morphology.

These various combinations of pollen/stamens and ovary/carpels produce many different zygotes.

Without the genetic ability to 'modify' particular plant parts into staminate structures particular species/lines of Cannabis would be unable to sexually propagate using natural biology and thus ceases to exist, period.

It is unfortunate that to grow sinsemilla we must ultimately select and produce a-sexually propagated individuals who stay 'true to type' to ensure that a consistent product is produced time in and out.

The alternative option of producing seed via (chemical reversal) to grow as a fast grown crop for sinsemilla production is not for the wise grower!

This breeding technique has a use in the production of agricultural superior cultivars but the technique is flawed many time's over if used incorrectly to create seed sold for 'growing some sinsemilla' in a hobby situation.

The exception to the rule is where the self-fertilized individual produces Gynoecious progeny after rigorous testing in the multiple relevant environments as explained above.

Gynoecious lines are artificial or 'Synthetic' they require pollen donors or must be inter-planted with monoecious pollenizer plants to produce the next filial generation sexually. (The only alternative is chemical reversal)

[Aardwolf]

As a consequence of the segregation and recombination of individual plants, which is often the case with pure-line populations, the constantly changing composition of open-pollinated populations virtually guarantees such populations will be less efficient and lower yielding than monogenotypic populations comprised solely of numerous identical copies of truly exceptional genotypes that have been identified as superior through repeated testing by nature, by farmers and/or by breeders, it is therefore not surprising that a common goal in seed-propagated out-crossing species has been the development of monogenotypic single-cross hybrid varieties.


A plants worth or value is assessed in its commercial viability or ability to re-combine with other individuals to create superior progeny compared to other individuals of the same breed.

A seed type is valued on 'purity' the ability to come True to Type and its superior performance compared to another under cultivation.

[Aardwolf]

Consequently breeders choose to make measurements on some familiar and convenient linear scale, such as centimetres in the case of plant height, or the percentage of individuals that are able to survive in a given environment in the case of survival. Both such characteristics often appear to be the end products of intricate chains of developmental sequences that may be expressed on non-linear scales.

Accordingly breeders sometimes convert convenient linear-scale measurements to some non-linear scale, such as log or square root scale that may shift allelic expressions in ways the breeder believes will more realistically represent gene expressions at the phenotypical level.

Moreover, the phenotype as a whole often depends on the "background" genotype of a population; hence when the scale of measurement is changed for one characteristic, the change may shift the expression of this characteristic relative to expression of other characteristics.

Further complications are likely to develop because background allelic and genotype frequencies and expressions may shift with environmental variations from year to year and/or from place to place. Thus breeders often attempt to identify and take advantage of various measurement scales in their efforts to develop superior agricultural populations form inter-crosses between pairs, or perhaps even among many promising parents, usually parents with compensating strengths and weaknesses. Yet what actually happens in most hybrid populations is likely to be so complex that it is rarely realistic to expect to know precisely what the genetic situation is at any given stage in the evolutionary processes that occur from generation to generation or from place to place.

Fortunately, exact knowledge is unnecessary because the usual experience, particularly with populations started from inter-crosses between two or more parents with differing strengths and weaknesses, is gradually increasing progress over generations, even in the absence of assistance from the breeder.

[Aardwolf]

I will suggest now that anyone who is not familiar with the terminology in this thread to pick up a book or google the word/phrase and learn.

This is not your thread to post your comments in, it is a thread to read and learn from.

I do not believe that people need to be cajoled into improving their understandings of the way things are, they must do it in their own time and leisure.

I assure you that my understandings of botany and biology are comprehensive I have nothing to hide.

So as the title says............

There are a number of Modern Breeding Plans which were developed from the standard procedures of selecting the “best.”

In the 19th century, nearly all plant breeders shifted to what is now called “classical pedigree method,” around this time learned breeders had the knowledge and practice of the early farmers.

Traditionally the old practice of early farmers and early breeders was to select numerous plants with particulars in mind and other characteristics they believed to be favourable, thereafter generation after generation they grew out the next generation or generations from mixtures of seed produced on selected plants the previous generation.

Such mass selection without progeny testing is the original and the simplest breeding method, historically it has been the most widely used method for breeding all seed-propagated crops, including Cannabis.

This selection based on visual evaluation or on simple measurements of the phenotypic characteristics of seed parents of individual plants, is referred to as Phenotypic Mass Selection.

This type of Mass Selection was conceptually simple and easy to conduct; further its single generation breeding cycle was appealing, it was not fully appreciated until the 19th century that the concept did not allow satisfactory controls of pollen parents in out-crossing species.

The problems with this method of Mass selection is such that under open pollination the successful pollen could come from any random plant in the population, including plants less desirable phenotypically than the selected seed parents.

The truth of the matter is the working of this breeding strategy wasn't fully understood at the time and it depends for success on high heritability-that is, on high regression of offspring on parents.

[WelderDan]

[M.R.GT]

relax and take a break. Oh Snap !!!

How to be a millionaire in one easy step.

First, get a million dollars.

You must spread some Reputation around before giving it to TomHill again.


I spit out my coffee when I read "I assure you that my understandings of botany and biology are comprehensive".

I assure you I have had more women than any of you.

OMFG.