Preliminary statistics for 2008

When hips abort, I put the tags in a bag. I later count them and use the numbers to do statistics in a spreadsheet. I finally counted the tags from 2008 last night. Here are the 2008 totals after three weeks of germination, along with the totals for two subsets of crosses:











2008 totals





crosses using
86-3 pollen





best crosses
of 2008









different crosses





96





14





12









pollinations





259





55





31









hips





141





15





31









hip set





54%





27%





100%









seeds





1225





60





539









seeds per hip





8.7





4.0





17.4









seeds per pollination





4.7





1.1





17.4









seedlings





370





26





276









germination





30%





43%





51%









seedlings per hip





2.6





1.7





8.9









seedlings per pollination





1.4





0.47





8.9







The number of pollinations is low because I don’t count hips lost to accidents or predation, and I lost a lot of hips to critters last year. Total hip set is low because I did many crosses with low fertility roses like Basye’s 86-3. The last column has the totals for the 12 crosses that have produced the most seedlings per pollination so far this year. Those crosses have produced about 19 times more seedlings per pollination than the crosses with 86-3.

I update my spreadsheet as more seedlings germinate, and when I decide to keep a seedling until the next year. At the end of the season, I’ll calculate statistics like keepers per hip and keepers per pollination. Those numbers will give me a better idea of which crosses are worth repeating.

Hi Jim,

I was curious about the difference between the pollination statistic and the hips statistic. You said 259 crosses and 141 hips. Did you differentiate between unsuccessful pollinations (ones that didn’t even start) and aborted hips that fail after looking like they are successful? I have one rose in particular (a miniature called ‘Antique Rose’) that is a big tease as far as aborted hips goes on pretty much any pollen I use. It develops and looks like it has taken, starts to swell and even starts to colour, and then dies and drops off cleanly with no seeds in the hips. It would be interesting to map days after abortion vs days after pollination to see if there are any patterns that we might be able to exploit to try and ward off late abortions.

try and ward off late abortions

Among the many tips provided by Wendy White was not to feed nitrogen to rose plants that have set hips in order to prevent this problem.

Hi Don,

I don’t feed my plants as a rule once I’ve started pollinating (mine are all in the ground too)… I read on Paul’s website that he also keeps the nutrients lean to encourage hipset and I have done this for a while (make them think their throat’s been cut and their survival instincts kick in). They are deeply mulched (mostly) and that’s all they get. I just think there are some roses that find it more difficult than others to ‘go full term’.

I lost a few hips to deer, but the vast majority of my critter losses were due to gophers. Everything is planted in gopher baskets, but when gophers girdle the roots, the plants go into shock and drop their hips.

Simon wrote:

It would be interesting to map days after abortion vs

days after pollination to see if there are any patterns

that we might be able to exploit to try and ward off

late abortions.

Simon, I haven’t done this. Please let us know if you try it. I don’t get very many late abortions, but most of the ones that I do get are either due to empty hips or damage to the mother plant.

Simon

Have you considered that Antique Rose might be a triploid? I’ve had it for many years & it’s never set hips in my garden.

Hmmm… what’s the ploidy of ‘Little Chief’? I was assuming it was tetrapolid because the cross was 'Baccar

Simon,

I think its highly likely that ‘Little Chief’ is either a diploid or triploid. It sets seed only sparingly, but its pollen is fertile, which is how you would expect a fertile triploid to behave. I should have David test it to confirm.

Do you have ‘Little Chief’? I recommend it highly for experimenting in creating new shrubs. It has a lot to offer.

Paul

(sorry for hijacking the thread Jim). I don’t think I have ever seen ‘Little Chief’ here and will need to keep searching… it’s not in the Ruston’s catalogue but then a lot of miniatures aren’t… if ‘Antique Rose’ is a triploid that produces next to no pollen it’s pretty much a dead end then huh… hmmm…

RE: Antique Rose…I learned years ago that if you want to make any serious progress in a breeding program, you can’t afford to spend too much time and effort on roses that don’t want to do the work you ask of them. As most breeders will tell you, volume is your friend. IE: You have to grow a lot of seedlings to find winners.

That said, I do think its worth your while to spend some time experimenting with long shots, but only as long as your big efforts focus on working with very willing breeding plants. Just my opinion, of course. Some breeders prefer to spend more time experimenting, and producing marketable results isn’t necessarily their goal, and thats fine too.