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xbrpete

Hybrid Vigor ........heterosis , An Explanation

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Not many are using this term to describe the actions of pollination and offspring in cannabis. We hear the term "Hybrid Vigor" used with increasing regularity to describe so called "strains" which are in actuality the repeated crossing of a male and female to create a succession of vigorous plants from seed.

 

First, an F-1 is NOT a strain, it is a stepping stone in selective breeding, a repeatable experiment that with stable parents can be used to create through long term clone maintenance a series of breedings that are or COULD be similar to the initial cross of male - female partners. One must also consider genetic drift in that environmental influence can and will cause either male or female plants to change in adapting to any differences.

 

A male or female that is kept at one location, under one strict set of environmental conditions from the first day my hold true. If one were to take that same plant to a different environment, it will adapt. Future expressions will be influenced by this change and the offspring will change to reflect this change.

 

Many of the so called "breeders" of cannabis do not take the time or make the effort to lock down the traits by taking the F-1 to F-2, back breeding and working thru the selection process to assure the person that buys their offerings will find the expression of the parent, parents or combination .

 

A good paper on Heterosis....

 

Abstract

 

Heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of development, and fertility than both parents. Various models have been posited to explain heterosis, including dominance, overdominance, and pseudo-overdominance. In this Perspective, we consider that it might be useful to the field to abandon these terms that by their nature constrain data interpretation and instead attempt a progression to a quantitative genetic framework involving interactions in hierarchical networks. While we do not provide a comprehensive model to explain the phenomenology of heterosis, we provide the details of what needs to be explained and a direction of pursuit that we feel should be fruitful.

 

Selected Excerpts

 

WHAT IS HETEROSIS ON THE CELLULAR LEVEL?

 

The developmental program of hybrids is not dramatically altered, so a specific type of quantitative trait is involved, namely, greater cell proliferation. Heterosis can vary in different crosses in different tissues. Flowering time often changes in hybrids, but depending on the species, the heterotic phenotype can involve either faster or slower progression to flowering. It has been argued that slowing the time to flowering will prolong vegetative growth. Whether this is a valid principle for heterosis remains unknown but certainly breaks down in crosses in which flowering time is sped up in hybrids together with an increase in biomass and fertility

 

Link to the study

 

http://www.plantcell.org/content/22/7/2105.full

 

© 2010 American Society of Plant Biologists

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Many of the so called "breeders" of cannabis do not take the time or make the effort to lock down the traits by taking the F-1 to F-2, back breeding and working thru the selection process to assure the person that buys their offerings will find the expression of the parent, parents or combination .

 

 

 

this is the main reason i do not often mess with seeds.....

 

ty for the explanation and link, pete.

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Fully agreed. I used to listen to Highbreed talk extensively on this subject. It's not terribly far past Mendel's law that I start getting lost. Those who don't take the time and/or make the effort are known as "pollen slingers" or "closet hacks" ;)

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Fully agreed. I used to listen to Highbreed talk extensively on this subject. It's not terribly far past Mendel's law that I start getting lost. Those who don't take the time and/or make the effort are known as "pollen slingers" or "closet hacks" ;)

 

Pollen chuckers!!! I hate em! :LOL:

 

Great info pete, thanks! This is something I have been meaning to learn about. Great topic!


Disappointment is caused by unrealistic expectations. / The more I learn about people the more I like my dog. / Whether you think that you can, or that you can't, you are usually right. / Its like everything it depends on everything else. 

 

 

 

 

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For a scientific paper related to what I have stated, the following study:

 

Zi Cheng Xu : Jun Zhu ....Department of Agronomy, Zhejiang Agricultural University, Hangzhou 310029, China

 

An approach for predicting heterosis based on an additive, dominance and additive additive model with environment interaction

 

Abstract:

 

A method is proposed for predicting potential heterosis of offspring of crop hybrids by an additive, dominance and additive additive model (ADAA). By using unbiased predictors of additive and dominance, as well as additive additive effects, general formulae for predicting heterosis over mid-parent and heterosis over the better parent are derived for different generations. When there exists genotype by environment (GE) interaction, formulae are also derived for predicting interaction heterosis. Heterosis in a specific environment is the sum of heterosis arising from the main genotypic effect and that arising from GE interaction deviation. The epistasis heterosis (AA) could play an important role in the use of heterosis for both an F1 hybrid and its later generations. In addition, a simple formula is given for predicting the number of generations of a cross that would still keep a certain level of heterosis over the better parent. Data from a diallel cross of cotton are analysed as a worked example for predicting genotypic value, heterosis, and the number of generations for each cross when heterosis over the better parent is larger than 5%.

 

 

http://www.nature.com/hdy/journal/v82/n5/full/6884800a.html

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f1's also require you to crack several upon several in order to increase your chances of getting a desirable pheno. Even stable genes have a handful of phenos, so a pack of f1's could very easily NOT contain any of what you desire, which you won't know until you grow them up and flower them out.

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f1's also require you to crack several upon several in order to increase your chances of getting a desirable pheno. Even stable genes have a handful of phenos, so a pack of f1's could very easily NOT contain any of what you desire, which you won't know until you grow them up and flower them out.

 

Breeder dependent but gotta say.......Perzactly!!!!!

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