Ploidy Mutation?

I was wondering if anyone had any information or thoughts regarding incidence of ploidy mutation?

One of my banks hybrids seems to be sporting and I suspect there might be a change in ploidy.

Changes include an increase in petals and prickles and some changes in coloration and blossoms last longer on the plant. The new plant seems to be bushier than the original with shorter flowering stems.

David indentified this one as a triploid.

Wow, it’s definately possible. The blooms lasting longer especially sticks out to me. The cells are larger in polyploids and it seems to result in longer lasting, stiffer petals. I noticed this on my tetraploid polyanthas and especially a tetraploid rugosa from Joan Monteith.

In the paper:

Kermani et al. 2004. Oryzalin-induced chromosome doubling in Rosa and its effect on plant morphology and pollen viability Theoretical and Applied Genetics 107:195-2000.

they report changed characteristics of the diploid and tetraploid versions of Therese Bugnet and I think Martin Frobisher and also the 3x and 6x versions of a David Austin seedling. Many of the traits changed (petal # and others) between the two different ploidies. Surprisingly many of the changes were not consistent across genotypes. For some the induced polyploid for instance may have more petals, but for another less.

I look forward to what you learn about the relative fertility levels of this unique branch versus the rest of the plant Robert. Has the leaf morphology changed (rounder wider leaflets)? This is a really neat find.



Yes, the leaflets are more normal looking while still maintaining a banksia character. So far it look much superior except for the increase in prickles. It resembles a China a bit.

I discovered this sport in a bunch of cuttings I stuck for propagation. As soon as it flowered I recognized it was much different.

The growth habit and leaflets of some of the banks hybrids look a bit confused for lack of a better term. The new growth twists and some of the leaves are puckered and contorted.

Now the $60,000 question is, is it fertile, and what does it pass on? I do see the anther in that photo…

Is that a sport of L.B. Robert, or one of her offspring?

On the subject of sports, I had been wondering… well, heck, that belongs on another thread…

This is a sport of ‘Riverbanks’.

See link to see what it normally looks like. I would assume it’s fertile, as is Riverbanks.

I’ve isolated the mutation. It will be producing a second flush of blossoms soon.

One of the things I like about this sport is that I can see the phenotype of each of the ancestors in the blossom.


Yes. Sorry, I was getting Lila Banks and Riverbanks confused.

Pardon my confusion, but Riverbanks was determined triploid correct? Are you speculating then that this sport might be tetraploid? I read your first post to mean that the sport was triploid…

Yes, I suspect ploidy mutation. I hope to eventually send David some more material for testing.

The blossoms last much longer than those of Riverbanks. There is phenotypic change in the plant as well.

Very cool and interesting.

Jim Sproul

I am finally able to update the progress of my Riverbanks sport. I disbudded the last flush in order to give the plant a chance to gain some strength and so far it looks very good.

I’ve decided to call it ‘Bankside’.

I madeup a HMF page with some updated information.