How to know how many plants I need for breeding?

Right now, I’ve created a list of all the crosses I’d like to make this coming spring. This is my first true year of breeding, so I don’t actually have any of the plants yet. I’m planning to buy them soon so I have them somewhat established this year for next year.

The problem I’m coming up against is this: each rose plant based on its class alone (not to mention traits unique to the variety, climate, soil, etc.) could have drastically different numbers of actual flowers. For example, I may only get 10 flowers at a time on one plant but 30+ on another.

If any of you were to give me (extremely) vague estimates for how many flowers I could expect from each class in the first 1-2 years, it would be immensely helpful! Also, I’m planning on starting the first year with roses in large containers (I believe Jim Sproul does this, and potentially others). Then, I’ll eventually plant the ones I’m certain I’ll use in the future into raised beds either outside or in a greenhouse.

I realize the numbers could be totally off, but I need to make my decision based on something–even if it’s a wild guess. At this point, I have no idea.

Thanks for any suggestions!

For me, the only class of rose that is consistently stingy with blooms are the hybrid teas. Shrubs, floribundas, pretty much everybody else gives me more blooms than I can use. You will find that year 1 for any rose is slower- if you’re in a hurry, I would pay extra for larger plants. If I could start again, I would be clearer on my goals, and invest in fewer, better plants. It’s not hard to generate a lot of seedlings- but generating a lot of healthy, vigorous seedlings is a challenge that still eludes me.
Another point: individual cultivars vary greatly within classes. If you give us some idea of your goals, we might be able to name a few productive, healthy parents.

How many flowers per plant depends upon SO many variables… There are minis which don’t flower a whole lot and others which flower like weeds. The same goes for each of the other types. Add climate and cultural influences and you really muddle things up. Are you considering making hundreds of pollinations or fewer? How many parents are you planning to use? You might consider starting with two to three of each and seeing how they serve you the first year or two and scale the quantities greater or fewer as you determine their suitability. I think you will find that after a few years, you will know which ones you need or want greater quantities of.

As mentioned by others its going to vary by goals, location, available space, cost, etc.

The other variation is some roses produce 25+ seed a hip while others are lucky to produce 4.

Dang, you’re totally right! This is so much more complicated than I first thought. I appreciate your input.

Yes, roseseek and donald_vancouver, you’re right. It’s probably extremely difficult to give a good estimate. However, the concept that shrubs and floribundas seem to give more flowers is a useful one. The idea that hybrid teas give less is something I was definitely already thinking. I mean, they’re mostly only one flower per stem. Then, as plazbo pointed out, different roses even give you different numbers of seeds in general. That, in and of itself, changes a lot!

At this point, would it be useful for me to give a list of roses I’m potentially thinking of using and the outcomes I’m looking for? Maybe then it’d be slightly easier to decide.

Thanks again, everyone!

Yes, easier to decide, though not necessarily easier to receive accurate suggestions. Many types set copious seed in one climate and refuse to set ANY in others. Some types make only petals in some climates with zero sexual parts, while in others they make semi double flowers full of stamen, anthers and stigmas. I’d read the reports of using Iceberg as seed parent and thought, "Hm, more deliberate ‘rose fiction’ " as it NEVER set a hip in the hot, inland valley-desert heat of Southern California. Get out in the cooler beach and it’s a bloody fruit producing machine! Mermaid? Nope, no hips in the heat, but actually a decent number in the cool, damp. They won’t germinate, but they are produced.

Repeat pollination can increase the number of hips set, as well as the number of achenes per hip.

de Vries, et al. (1983)
25 flowers, pollinated once, gave 12 hips averaging 8.6 achenes per hip. (103 total)
25 flowers, pollinated five times at 24 hour intervals, gave 23 hips averaging 16.9 per hip. (389 total)

These results were for the cross Sonia x Ilona. Results would likely differ for other crosses.

That’s a point I never considered. In China, I volunteered at a breeding program this spring, and they only pollinated roses once. However, in the RHA booklets (and elsewhere), many suggested pollinating more than once. Rather than getting more plants to pollinate, I feel it may make more sense to increase the actual pollinations per plant. Thus, it could increase the hips/seeds without increasing the plants I need to buy! At least, it’s worth a test.

Thanks everyone!

John Cook was a prominent rose breeder a century ago. His ‘Radiance’ was once the most popular rose in the U.S. He warned us not to skimp on the pollen.

Cook: Rose Hybridization (1905)
As the pollen sometimes is very scarce, it is better to put it only on two, or three pistils, repeating the operation the following day.

Cook: Some Interesting Results in Rose Hybridization (1906)
It took twenty flowers of the Marechal Niel to produce enough pollen to fertilize one flower.

I can believe that about Marechal Niel! That bloody thing is STINGY. Two to four stamen per bloom? I won’t have enough to mess with until the plant eats the entire block.

Off topic, but thought of it when you talk of stingy pollen producers. As I’ve mentioned in another thread, I highly recommend getting a pocket microscope. A friend gave me a 40X one that was about a 4" aluminum tube the diameter of a pen. That worked well. Use a black bottle cap or a folgers lid to put the pollen on, and illuminate the pollen with the flashlight on your phone. I’ve recently bought, as mentioned in another thread, a 120x with its own light. Works even better. The scopes that hook up to your phone or computer don’t seem to have enough magnification regardless of what they say in the description.

Anyways, taking a look at the pollen under magnification is a great way to predict how fertile the pollen will be. Some roses produce pollen that is entirely misshapen little globs that make you wonder if any is fertile…in my experience it’s probably not. Triploids (often) produce a mix of nice oval grains and smaller grains, including misshapen ones. Other roses such as a straight rugosa or species roses produce lovely, uniform little “eggs” of pollen that indicate great pollen fertility. When using pollen of intermediate or poor fertility it is especially important to smother the stigmas with pollen, and perhaps re-pollinate later in the day.

Michurin had a similar problem with ‘Persian Yellow’.

“As for those cases when it is required for the purpose of crossing the pollen of varieties of R. lutea and especially Persian Yellow, I managed to find an easy way to make the anthers give it. To do this, you only need to take off half-opened flower buds early in the morning and then spread them on dry paper in the shade, best in the room where they give enough pollen by the next morning, which is most convenient to collect from the walls of a glass jar or glass, before filled with ragged stamens”

Please excuse the odd phrasing. Google translate is a wonderful tool, but is not at its best translating Russian.

Yes! I read your other post, and I definitely plan on getting some kind of microscope. I believe I read in the RHA Next Step’s booklet that you can estimate somewhat the ploidy based on pollen size. I’m not entirely sure how accurate that is, but I already planned on testing that theory. Now, I have another, potentially more practical, reason to get a microscope! Also, I’m going to do a bit of digging to see if there are any decent quality digital microscopes which attach to a phone. If I find anything, I’ll definitely share.

Thanks for your tips!