For flowering plants when crossing a given diploid X given tetraploid of closely related species, what causes some of triploid offspring to be very seed fertile while most are sterile? We are working with diploid and tetraploid species of North American deciduous azaleas.
It seems to be the case that the less viable seed produced by the diploid X tetraploid cross the more likely at least some of the offspring are fertile.
Note: We have done flow cytometry on the fertile offspring and both the fertile and the nonfertile test as triploid.
Dear Perkins
As we all know that, triploid progenies of diploid x Tetraploid crosses are sterile due to abnormal dis junction of chromosomes during meiosis. But fertility may also be encountered in some of triploid progenies (which may have specific gene combination to cause selective elimination) may be because of selective elimination of chromosomes from either of parents. Especially from tetraploid parent would lead to the surviving pollen containing only "n" number of chromosomes. this selective elimination of chromosomes is also explained in bulbosum technique of wheat haploid production.
Thank you
Dear Chetankumar Banakar
When using the seed fertile triploids as seed parents and stable tertaploids as the pollen parents, flow cytometer indicates that most viable offspring are aneuploids between triploid and tetraploid with a few additional offspring being close to triploid, a few close to tetraploid, and few close to pentaploid.
Dear Perkins mam,
You have used fertile triploid(3x) as a female and tetraploid as a male. in nature anueploidy is tolerated more by female gamete than the male gamete. so viable aneuploids can be expected upon fusion of aneuploid female gamete with normal diploid pollen ( from 4x parent) but they are sterile. if by chance we get fertile progenies, indicate there is a homeology exist between the chromosomes of two species used in cross. which can eliminate or compensating the effects of anueploids.
One progeny of fertile triploid X tetreaploid measured as pentaploid using flow cytometry. This pentaploid has proven to very fertile as a seed parent. So far the progeny from 3x X 4x that measure aneuploid have not bloomed so we do not know if they will be fertile.
Dear Dr. Perkins
Do you think not blood aneuploid due to saturation of inductive environments or what, it is interesting.
In crossing the offspring depend on which was the mother terta or tri and which the father was. Tribloid is not usually sterile it depend on the final chromosome number/2 of the offspring. In some instance at anaphase chromosomes are not separated equally to the cell pole where telophase commenced. Offspring posses of odd chromosome number more likely to be sterile.Besides, chromosome number vulnerable to alteration, particularly during division.
Caser Ghaafar Abdel
These aneuploids are only four years old so it to early to tell if nonblooming is due to aneuploidy. Diploid deciduous azaleas often do not bloom until 6 or 7 years old when planted directly outside after the first year.
Often triploids and hexaploid bloom at a younger age than diploids or tetraploids. Both have been known to set flower buds the first year. The pentaploid from triploid X tetraploid bloomed in the third year.
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