Making inbreds is the most important step to develop hybrids, and it is not always easy to find genetic variations, so, some researchers try to get some new inbreds from same old inbred, by selfing different plants in color, stature, ear length,...etc which character is better to start on , quantitative or qualitative ?
Today became it's not difficult to find genetic variations, by using the recent technology and decoding the genome of most plants, including rice and symbols .. It's bioinformatic.
sure for produce new version of an inbred line, the better to start on qualitative trait because it's have simple structure concer his genes.
You can access the gene to look for in the genome sequence, but provided that you know how !!
Therein lies the modernity.
best regards,
Fouad
I realize that qualitative traits have limited number of genes, so i believe it is less likely!However the high positive correlation may be give better result!
its up to your focus. to answer the question I would say Qualitative. Actually to develop inbred lines there are some basic/essential characters, which we want to keep anyway and then like to add some more characters (if addition is like disease resistance character) then its quantitative. In my view if DH protocol is available, then its easier to fix targeted character. Using DH technology even recessive genes also become homozygous and chances of their expression increase (make sure for linkage and Epistasis)
Regards, Arun
The question was targeted developing a new inbred version from an old inbred to have a higher yield hybrid. For hybrid vigour cant be judged to be controlled by a few genes !, then quantitative characters sound to me the most likely ! Regards
Inbred line to get only Hybrid Vigor, or I would say more vigor. That's why I put my comment Focus/Target of integration of which characters is there by Breeder. if a hybrid is high yielding having good color, taste etc., but disease susceptible for any specific disease which become threat then what?
Regards, Arun
1) selfing of F1 to generate segregate F2 by crossing with diverse inbreeds for triaits, and from segregated population selfing for 7-8 seasons to get pure new inbreds. (MAS can also use to save time)
2) BIL, RIL s also give new inbreds , multi parent cross step by step (qualitative traits with different genetic back ground)
Dear Pulipati : The question was about another thing, please go back and read the question ! Thang you so much for answering.
Dear Prof. Medhat
The inbred line can be created by close relative mating, beginning from the large population or from the old inbred line, but the degree of homogeneity of the old inbred has an important effect ( I mean are there fixed allele and losing alleles or not ).
The important effect must be considered from the increasing of inbreeding coefficient is the inbreeding depression which causes reduce in viability and fertility of the flock ( the probability of inbreeding depression will be high by using old inbred lines ).
Good Luck
Dear Dr. Hasan: i believe your answer still far away from my question, what you mentioned is correct fo the inbred situation, but it is not the case of the question!. Thank you so much .
Consider back crossing of old inbreds like that of tropical x temperate has been used for improvement of harvest index and ultimately the yield (quantitative trait).
Yes ! Khan , it sould be quantitative, for grain yield vigour relies on many genes , not a few in general at least !
I would suggest that first the breeder should be clear about the target of interest. Either Qualitative or quantitative. Qualitative should be preferred due to easy inheritance patterns and high heritability. In coventional breeding you can cross an inbred line to a genotype from which you would want to add particular trait of interest and follow its introgression in the progenies(new version of old inbred) through selection . But nowadays through MABB it is easy to intogress an additional trait e.g. high Vit A in the background of otherwise superior old inbred (High yielding with low Vit A) to achieve the new version of old inbred which is now called as introgressed Inbred. Conventional breeding has limitation that only you can select phenotypically visible traits but not for biochemical etc.
Dear Choudhary : The question was about selecting some different plants from same inbred that happens when we have large area planted with that inbred, is the selection should be focused on qualitative or quantitative character to have a new inbred version of more grain yield Vigour?
Ok you are talking about within line variation. Yes if objective is to get high yield then you have to target quantitative characters from beginnin because yield is a polygenic trait.
Dear Medhat Elsahookie i would to share my experience. Instead of grain yield you should go for the allied traits. Because you are not aware of what will happen with your derived inbred in a cross combination. So in that case you should focus on allied traits e.g. number of grain rows, pith size, Cob size, grain size.
Thank you Coudhary, now you got the idea, and I do agree with you, thankind you so much.
Dear Shaheed, thank you for you answer, and I agree with you that selecting aolygenic trait is the best way to improve grain yield of a new line version.there was so many studying with me in KSU, USA, finished his PhP in corn breeding, his name Salim khan, please if you something about him let me know, thanks in advance.
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