Hembrain said:Oh, wow. So a conversion can sort of do a slo-mo fail, reverting back to the diploid state, in part or even potentially completely?
Yes, only complete conversions are safe from reverting back to being diploid. In the early years of tetraploid conversions the advice to anyone thinking of buying a converted plant was to do so only if the seller had checked the plant recently for its tetraploidy status - by examining pollen or stomata with a microscope.
Also, Arisumi, a plant geneticist published his research on converting diploid daylilies to tetraploids. He did something specifically to reduce the possibility of losing the tetraploidy when he treated his plants. I do not know, but I suspect that those who convert daylilies nowadays do not do what he did.
Nowadays crowns with one fan of leaves are treated. The main growing point is treated after the leaves are cut down severely. Arisumi did that. But once the treated growing point started growing again after the treatment was done, he removed all the rest of the crown around the growing point and forced what was left to sprout new roots. By removing all the rest of the crown Arisumi removed all other untreated (diploid) growing points on the crown. If that is not done then over time, when the treated plant increases from one fan to many fans some of those untreated growing points may sprout and produce diploid fans. That can happen even when the treated fan produced a complete tetraploid.
The end result is that over time there are two ways that a converted tetraploid daylily may revert back to diploid.
1) It was only a partial conversion and the diploid parts manage to replace the tetraploid parts
2) diploid growing points were not removed and they later sprout to produce diploid fans in the clump so that it becomes a clump of both diploid and tetraploid fans.
So, it could be POSSIBLE that my dip and tet Lillian's Thin Ice act the same because they are both acting as dips?
Yes, that could be possible. It is important to understand that the more years have passed (the older the tetraploid conversion becomes) the more likely the clump is no longer all tetraploid - if it was not a complete
tetraploid conversion originally.
When we use a seedling of the converted dip, say Tet RFK, are the genes are more stable and fertility more reliable?
Only the treated plant itself can possibly revert. Its seedlings are completely stable. Their fertility is normally better than that of their converted parent. The hybridizer who made the crosses using the converted parent would know the fertility of the seedlings that had been selected. Their fertility may or may not be the same as the general (non-conversion) tetraploid population. To know that would require a special analysis.
So, if I use, say, Dancing Flamingo (Cutting Loose x Tet RFK) as a parent, I may have better success with the crosses than directly working with Tet RFK?
As long as better success means a higher percentage of pollinations successfully set pods and produce seeds that is generally
what to expect. Specifically
, that depends on the actual fertility of the Tet RFK conversion and of 'Dancing Flamingo'.