back-X Ineffective in selecting mj heterosis

[syk613]

Authors

Stepanov GS. Sytnik VP.

 

Title

[ineffectiveness of the back cross method in selecting hemp for heterosis]. [Russian]

 

Source

Tsitologiia i Genetika. 12(5):424-7, 1978 Sep-Oct.

 

Abstract

In the back crossings the heretability caused by the additive effect of the genes predominates. The selection on the characters controlled by the additive genes leads to the homozygosis increase of the population and to the reduced vitality of the plants. The repeated crossing of the heterozygous hybrid plants with the parental form homozygous according to the recessive gene increases the quota of the genes of the latter. It results in the intermediate type of inheritance for all the elements of the back crossing hybrids productivity.

 

 

I'd try to explain this but I have v little I could add and be absolutely sure of the info.

[pipeman]

I can sum it up in 4 words: backcrosses have less vigour

[syk613]

uhm, yeah... but why ie this sentence

The repeated crossing of the heterozygous hybrid plants with the parental form homozygous according to the recessive gene increases the quota of the genes of the latter

[pipeman]

to quote Spock, I cannot answer if I do not understand the question.

[syk613]

oK sorry but the abstract is talking about why the plants are less vigorous after back-X and that is what I wanted the detailed explantion about, I think the puntuation of the orig. article is not the best but I will take a look at some genetics books thanks pipeman its been a bad day

[pipeman]

bad day? shit I'm sorry to hear that. maybe if you focus more on smoking the stuff instead of analysing its genetics your day will get better. In fact I know it will

 

don't mind me mate, its good having someone around that knows about this stuff, makes for some interesting reading when I'm ripped off my tits.

[syk613]

Yeah my day was shit but looking through a journal database on the web(took me 5 mins) and smoking a few was the better part and hopefully it will inspire a few others esp. possible med users to take a look through the research and discover some facts altho this and the few other posts have been more for breeders or just general interest, lots more of these on the web tho so any subjects anybody is researching or interested in I'd be happy to try an find some info or point you in the right direction.

[pipeman]

I am interested in how growing conditions affect THC/CBD content of your buds. Like does CO2 just increase yield or does it increase potency as well? Also I've read the humidity levels late in your grow can affect what kind of high your buds give.

[syk613]

I'll take a look before monday (probably), i'm not sure if this info will be in a medical /biological journal but a previous abstact posted looking at these molecules was done by a company in Amsterdam so I am not sure but i'll try. any keyword suggestions like thc, cbd and full names etc

I'd be interested to know the answer to this question also.

Edited November 6, 2003 by syk613

[white_cluster]

backcrossing is only really done because of the fact no same strain male pollen sources exist, and it would take a very keen eye and alot of progeny testing to linebreed selecting plants with traits of the females. Its only usually done 4-5 generations, probably a tiny drop in vigour, and not to useful as breeding plants, but still, linebred stable strains are rare as all shit, just cultivators choice and DJ short strains really.

 

But it doesn't matter, all you want from the backcross is a plant similar to the clone it was based on, and you'll get it. I noticed romulan a strain with 7 backcrosses was the least vigourous plant I've ever grown, But it could be a trait of the original clone.

 

Something that just made me think though, if you took a backcrossed plant that was backcrossed ass far as it could go, but you were looking to stabilise a recessive gene into 99% of specimens instead of 50, would you be better off linebreeding the backcrossed line or starting again with the original clone that showed the recessive trait??

 

like after a clone is backcrossed could vigour be re-established through linebreeding those seeds???