Does ploidy(alloploidy or autoploidy) level and chromosome number affect the endosperm not to support the development of developing embryo in interspecific crosses? especially crosses between wild species??
Can anyone please tell the methodologies to study the reasons for the fruit drop after 3 -4 days after pollination? Can anyone share the protocols for any microscopic studies for this, if available?
Possibly yes. Most wild relatives generally have higher ploidy numbers and domesticated are most diploids. I assume there is a relation interlinked with embryo and endosperm support as in banana the triploid, example shines. May be in others to such events happen that we may not look or observe and take into account.
Yes, it can happen. This phenomenon is discussed under post-zygotic barriers to distant hybridisation. The genetic composition of the embryo, when different from the maternal tissue can get aborted. True, the endosperm is hybrid but 'imbalanced'. In 2x x 2x crosses it will be triploid and when different ploidies are involved it will be further imbalanced. So if your fruit is dropping after fertilisation, best way to get plants from the cross is embryo rescue.
We have done this in interspecific, interploidy blueberry crosses. The paper is in ResearchGate in my profile, not sure if this link will work.
https://www.researchgate.net/publication/279182192_Ovule_Culture_and_Embryo_Rescue_Facilitate_Interspecific_Hybridisation_in_Blueberry_%28Vaccinium_spp.%29
Article Ovule Culture and Embryo Rescue Facilitate Interspecific Hyb...
Flow cytometry of open pollinated seed from triploid deciduous azaleas indicates the ratio of the embryo to the endosperm is normally close to 2/3. This seems to be the case independent of the flow cytometry score for the embryo.
This seems to indicate successful seed formation is associated with equal contributions from both parents rather than on the focus being on the size of the contribution by a given parent. In the case of a triploid deciduous a contribution of 1.5x by both parents appears to be as success in terms of successful seed formation as either something close to 1x or 2x by both parents.
Put another way having a embryo / endosperm ratio close to 2/3 appears to be more important than the embryo being close to euploid when it comes to successful seed formation in triploid deciduous azaleas.
- Badges
- Science method