Timing of Pollen Application

I am wondering what others think of this. Early on, I did my crosses by removing petals and anthers from the prospective mother plant, then waiting until the next day to apply pollen. I had heard that you had to wait until the stigmas were sticky to apply the pollen. I thought too, that maybe the pollen would just blow away and be gone if there wasn’t a sticky substance to hold it there.

For the last 7 years or so, I have applied the pollen just after the petals and anthers of prospective mother plants have been removed. It seems that I have a better hip set rate now than before and it is much simpler and quicker, plus I don’t have to try to go back and find all of the blooms that were emasculated from the day before.

I think what is happening is that the stigmas initially while not sticky, they do have a very rough surface that will hold the pollen in place. Also, I think that the pollen helps to initiate the formation of the sticky substance. Finally, since pollen remains viable for at least 24 hours, that is usually plenty of time for the stigmas to become receptive to the pollen that is already there.

Any thoughts?

Jim Sproul

Jim one consideration would be if the pollen sat in the hot sun on a dry stigma, it could degrade from the heat.

Jim, I do the same thing - pollen immediately (and then later in the day and once more the next day). The stigma is so craggy, one would think it would stay put even before it is sticky. I’ve had trouble getting hips though when applying pollen in this hot weather (110ish) at any time of acceptance, and I’ve just started covering the blooms with little hats to keep the sun off of the pistils for a few days after pollen has been applied.

As for your original question, I wonder if anyone has tried a light spritz of hair spray after the pollen is applied. If this works, it might be good to use if there is very little pollen being applied on an important cross. The downside to this, of course, is IF it works to keep the pollen in place, subsequent applications of pollen to the same stigmas might not work.

Jim,

I pollinate blooms immediately after emasculation, no waiting at all. The only times I have pollinated a bloom the day after emasculation was if I forgot to return to a prepared plant and discovered the incident afterwards. It doesn’t seem to matter in the least when I pollinate a bloom. I think that stigmas are quite capable of holding on to enough pollen to get the job done, regardless of how “ready” the stigma is.

As an aside, I do not cover blooms after pollination to prevent stray pollen “dirtying” my cross. I work on the IGTF Principle, which is to say: I Got There First! The amount of pollen I generally put on the bloom is overwhelmingly going to be the pollen to succeed in causing fertilization, and any stray pollen to come afterwards is going to be an insignificant risk, in my opinion. And yes, this applies to pollinations made out in the garden as well as under plastic.

Regards,

Paul

Great feedback. Thank you!

Here in the Southern San Joaquin Valley of California we also can get high temps, that’s why I usually do all of my rose breeding in April/May. During hot stretches, I have noticed a much poorer hip set and also have noted that on blooms that are forming during hot periods, that when the blooms finally open, even if the temps are back down into the 80’s, the pollen is very scant.

For me, the first bloom cycle is by far the best for rose breeding - more hips, bigger hips, more seeds and they have plenty of time to ripen (not that we have to worry about early frosts!).

Jim

Title: Successful Rose Pollination

Author: PERCY H. WRIGHT, Moose Range, Saskatchewan, Canada

Published in: American Rose Magazine, January-February issue, page 448, (1950)

Start of article:

“During 1949 I learned a lesson about the pollination of rose blooms that had escaped me in fifteen years of work.”

…Due to possible copyright I am only including the beginning and the end…

"This year the papers used for wrapping were all cut as strips, so that even when folded and tied on tightly, the open slits at the sides provided plenty of ventilation.

When harvest time came, the difference in results was astounding. The hips that had been left uncovered failed more often, and those that did “catch” were small, with less than a dozen seeds usually. On the other hand, practically all those wrapped with paper “caught” successfully and made enormous hips, with between 50 and 80 seeds each. The rose-seed harvest of 1949 was thus one of the most generously rewarding I have ever had.

I can only suppose that shading the pollinated pistils from the sun results in the pollen more often getting its chance to operate than when the exposure is complete. At present there is no evidence to suggest that the same phenomenon might be observed in pollinations made in the greenhouse; however, I have a notion that there might be a similar but smaller gain to be secured by wrapping the pollinated flowers even though the pollinations are made under glass. The variety of rose that served as the mother parent in these tests was the well-known rugosa hybrid Hansa."

When I began hybridizing in 1972, I thought that it was necessary to wait a while between emasculation and pollination. So I would emasculate flowers in the morning, cover them with paper cones to keep the stigmas from drying out in the hot sun, and pollinate in the evening. This technique worked, but I later discovered that it made unnecessary work.

One year I didn’t have time to make two trips through the garden so I prepared and pollinated on one trip. The seed set was just as good. Since I lived in Lubbock, TX at the time, I did continue to cover the pollinated flower with paper cones to keep the hot sun and low humidity from drying stuff out. I made a limited trial of the leave-it-uncovered technique and got poorer take with fewer seeds.

Here in West Virginia, I just leave the outer petals on to keep a more natural humidity level around the stigmas. Otherwise, we do not lack humidity, as the last 7 months of rain demonstrate. I would not put cones over the pollinated blossoms here because fungus would be encouraged (and it needs no encouragement here), but in dry climates such as Percy had and I used to have, the protective cones do help.

I pollinate the same time as I emasculate most of the time. I’ve never kept records of my seed set either way, but it seemed fine. Like Peter, I cover my pollinated buds with paper to protect them from drying out in my dry and windy climate.

Joan

Well, I’m a neophyte, so my experience is limited. I’ve been doing esmasculation and pollination at the same time. I’ve gotten reasonable seed set last year where I had abundant pollen. (0% germination, but I believe that’s attributable to too late a harvest)

Also because of limited time I haven’t been covering potential hips. (Two I did cover w/ foil actually look less healthy than the exposed ones and have since been uncovered) Last evening, I did some more pollinations, and my twin boys asked to help (3 3/4 yr old) So for sentimental reasons, I’d like these to take. We later got torrential rainfall. Is the pollen likely to wash off? Should I try to repollinate these after the rains stop? I have very limited time and many other garden duties calling.

Thanks.

I live in a very hot and dry climate and seem to get as good of a seed set outdoors as in the greenhouse, without covering the hips at all. In fact, there are some varieties that seem to produce better hips outdoors than in the greenhouse.

Chris, I am sorry to hear of your experience with poor germination. Sometimes it is the variety, sometimes lack of hip maturity and sometimes there may have been a problem with cold stratification. As for rain washing off pollen. If it rained more than 6 hours after your pollinations they may be safe. If it rained right after you made your crosses, then it would probably be best to redo the pollinations. If you live in a rainy climate, another idea might be to use minis in pots and keep them under a patio covering to protect them when it rains.

Jim Sproul

"Here in the Southern San Joaquin Valley of California we also can get high temps, that’s why I usually do all of my rose breeding in April/May. During hot stretches, I have noticed a much poorer hip set and also have noted that on blooms that are forming during hot periods, that when the blooms finally open, even if the temps are back down into the 80’s, the pollen is very scant. "

I have noticed this too, Jim. Would you not be able to do another round of pollenations in September when temps start to cool?

SunQueen, have you tried pollinating in the late evening?

When I do my pollinations in Apr/May, I usually take off about 2 weeks of mornings to do the pollinations and work at my job in the afternoon. In that way, I can make plenty of crosses and get 30,000 to 40,000 seeds each year- plenty for my operation. These rippen better and have more seeds per hip than at any other time - efficiency is key for me.

Later in the season, like right now, I do some experimental crosses with my new seedlings in the greenhouse (trying to speed long range plans along, to cut down on generation times). For instance, I have a new clean seedling of 'Baby Love that has a purple “blood” line in it, and I have a clean striped seedling ‘Roller Coaster’ X 'Michel Cholet’with the same purple line parent as the mom(neither of the above are purple. Well with my goal being a good clean floriferous purple striped shrub, I have crossed these two together because I noted that the new ‘Baby Love’ seedling sets hips well.

Jim

Jim

I am very meticulous, maybe to the point that a few may see me as anal-retentive. I cover pollinated blooms, and if I don’t, I make sure that I write “UC” (uncovered) in my notes. I usually do this only to keep my peace of mind. Funny really, in my life I’m a slob, but when I’m pollinating, I’m a super-neat freak.

Henry, yes, I am now pollenating in the evening AND using hats, and I do seem to be getting some seed set. I have a good deal of hips that were crossed in April/May but I’ve done a pollen swap and acquired some wonderful purple/lav/mauves that I’d like to use, but this time of year is tough so I have them in the fridge. Actually, that brings up a question. Should I put the pollen in the freezer instead?

It seems like some roses will set in the heat but most (of mine) won’t. I’m pollenating in early evening as soon as the sun is off the bush, trying to give plenty of time for the pollen to germinate and complete it’s journey. Does anyone know how long it takes for the ovule to be fertilized once the pollen germinates?

Jim, 30,000 to 40,000!!! OMG! Last year was my first attempt at hybridizing and I used OP hips from a friend’s very high quality garden. I was incredibly lucky to get some fantastic seedlings (see below), 15 of which are still growing in pots, but I’m at a loss to figure out what in the world I will do next year when this years’ crosses crop germinate! I’ve got 1-1/3 acres, but it’s all open desert. I’ve contacted the local University Extension and they are reluctant to rent out space in their greenhouse. We have no basements in Tucson, so I guess I’ll have to rip up the desert to grow next years’ crop. Keeping animals away will be a huge problem. Any ideas??

Link: home.earthlink.net/~judsinger/JudesHybridizedRosePage.htm

A cold frame, err rather…an anti-heat frame for you LOL. might want to search the net for techniques in using some sort of frame. A cold frame is rather inexpensive to build but I have no clue as to how a desert area would procede.

Putting roses in a cold frame in the desert is like putting them in an ice house in Alaska. It only concentrates the heat. Air conditioned greenhouse works, but that is extraordinarily expensive.

I know that =) What I am saying is that perhaps there is a desert version of a frame to protect seedlings outdoors. Also, Cliff needs to get on this discussion! Poor guy seems to be having heat problems, too.

ps. Enrique, that is not so unusual with rationals. One of my good friends is a programmer. He can do anything intellectually but lets just say aesthetics isnt his strong point. Just think of where us human critters would be without rationals!

-Mike

Maybe a below ground bunker…

Yes, this poor guy is having a terrible time. I seem to have chosen the absolutely hottest time on record to start as a newbie hybridizer! I’ve done 350 crosses in the past 30 days, with only two possible hips set so far. We’ve had days where the heat index reached 148F (119 actual plus over 30% humidity), and I can’t imagine that this is a good time to be conducting such activities. As Jim said above, it’s tough to get much pollen out of the blooms, even if the heat weren’t a factor in getting the hips to set.

I’ve nearly completed a review of my first thirty days, and will post it here for comments when it’s finished – probably in an hour or so.

For the time being, I’ve stopped any new crosses and will resume when the temps fall a bit.

Cliff