Ploidy in Modern Miniatures

I’ve been studying pedigrees and wondering at what point miniatures become tetraploid? It seems there are a great number of diploid ancestors in the not distant past listed in most lineages.

I had a germination using Moore’s ‘Softee’ as seed parent today. Any guesses as to the ploidy?

I noted that Softee pollen often results in aborted hips last season.


Become is not the proper word. Became is more precise.

Years ago I spent may be a full week studying this question searching MR. HMF had no tree lineage feature then. It would be a lot easier now!

First it is lucky for us that many Moore roses pedigree are known. And that he wrote a lot about his breeding procedures and achievements. Unluckily ploidies are mostly ignored.

After an all diploid crosses initial period, it is quite obvious that for tenth of years a few fertile diploid parents were used recurrently with Golden Glow and much more Little Darling. Both Golden Glow and Little Darling being allways the seed bearers. A tendency that became more and more the rule over the years. A tendency even more obvious for all others miniature breeders with often other repeatidly used tetraploid Fl mothers.

Very few Moore roses are available here Europe but from evidence and his own writings: Moore is breeding for HT flower colors, shape and sturdiness. And against HT plant size and architecture.

That many if not all modern miniatures parents that have these qualities are tetraploid is no wonder. The miniature gene is known to be a quite effective dominant one that has a reducing fertility side effect. To the point that when he initally used diploids non miniatures they were on the mother side. To the point that triploid miniatures are among the less fertile group one can find among roses.

Selected for fertility seedlings from a mostly triploid progeny from a tetraploid mother and diploid or triploid miniature father are more than probably the tetraploid ones.

This is obvious in Softeee lineage tree with the male parent bringing the miniature gene all from the male side (lower tree branch). And the diploid non miniature wichuraina being a seed bearer as well as Golden Glow and twice Little Darling.

Thanks Pierre. I suspect Moore merely repeated what worked for him over and over. He has typically ignored concerns regarding ploidy.

What you’ve pointed out here makes sense. I suspect there are still many modern miniatures of mixed ploidy which to my mind explains why they might be more fertile in one direction.

I have noted certain miniatures produce more large flowered offspring than others. Apparently though the miniature gene is dominant, it does eventually give way to full size offspring after several generations.

I prefer to breed full size roses. I realize most of my seedlings using these varities will be miniatures.

Sure! It is the more productive part of Moore tentatives. And he tried a lot! Every way. He is certainly an outstandingly perseverant breeder coping for decennies with such tiny flowers and low fertility steadily repeating the same crosses.

He is rewarded by unique outstanding achievements.

Many tetraploid miniature have only one miniature gene. And hence when crossed to non miniature can be expected to throw about fifty-fifty full size-miniature progeny.

Here unspraied the best miniatures are too much desease prone. Foliage is probably too close to ground.

Hi Robert, ‘Softee’ is triploid. I bought a couple to use in breeding this past fall and did root tip squashes on them a month or two ago. I have them growing under lights to get to a larger size to hopefully have more flowers to work with come spring.



AHA! Thanks David!

I new something was amiss! It doesn’t behave a though it’s fully fertile.

This makes sense. I had NO success with the pollen. Try it for seed.

This seems a bit unusual for a triploid as they are usually better as pollen parent but this was my experience last season.

Thanks! Robert