My method in a nutshell, esp. the case for using mixed pollen

Technique Overcoming Sterility
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1

I save time by using just 4 females: Oso Easy Italian Ice (The best.), SunSprite, my seedling (Italian Ice x mixed.) and one wild card: One of my seedlings I haven’t tried as a female that is a fine cultivar in its own right and looks like its sex organs are intact–Decent size ovaries, plenty of stamens, and 15-25 petals: More than 25 and the take rate exponentially decreases, fewer than 15 and I’ll get too many singles as progeny.

That brings me to what I believe is my best idea for small-scale hybridizers: Use mixed pollen of the few best varieties. Given my goal of creating a competitor to geraniums: healthy, HT form, on a windowbox-size or front-border plant: Rainbow’s End, a Por La Mar unnamed velvety red mini of HT form and surprisingly good health, and the aforementioned seedling. Of course, that restricts the information I get on crosses BUT the advantages are huge:

  1. I need do no labeling
  2. I need do no recordkeeping. I know that all my females except the Wild Card have good take rates, germination rate, and produce good stuff. I’ll just note, in my head, how the Wild Card does.
  3. I never run out of fresh pollen. I have so much that when pollinating, I can hit each flower once a day for the 2 or 3 most-likely days of receptivity so I’m sure I got it when it was maximally fertile.
  4. When I plant the seeds, I need do minimal labeling. I just have a section for each of the four females.

Through the month of November, when pods are reasonably ripe, I harvest, shell, and then soak the seeds for 10 seconds in a solution of 1 part Clorox to 9 parts water, wrap the moist seeds in a small piece of paper towel, moisten the toweling with a bit of the Clorox solution, and put the towel-wrapped seeds in a baggie (labeled with the female’s name) in the fridge. Through November, I add newly harvested seeds as the hips ripen.

In January (I live in Oakland CA–Zone 10) I plant the seeds in a planter table (20’ x 3’ x 10") 1,500-2,000 seeds per year. I plant them 1" apart. I get a roughly 25% germination rate, which means 350-500 seedlings 2 or 3 inches apart. In March or early April, if a seedling is growing vigorously and otherwise looking good right next to a weak one, I’ll scissor-out the weak one so the good one has more room to grow. If it’s next to a good seedling, with a spoon, I’ll carefully transplant it into its own 4" pot.

By mid-June, I’ve seen first blooms from most of my seedlings. Those that haven’t yet bloomed yet, I dump. I also dump all singles, unattractive flower, any disease, poor vigor, etc. I look for hybrid-tea form, health, vigor (yet still compact) floriferousness, good foliage. By the end of June, I’m down to about 10 seedlings and by November, typically 2 to 4.

2

Thank you. I would be concerned with the use of Clorox (lungs). Did you try hydrogen peroxide?

3

You’ve inspired me to try my first pollen blend. I am so tired of organizing vials of pollen, and now that I’ve narrowed my breeding goals I think a pollen mix of the right staminate parents might do the trick.

4

I used separate pollen for a few days. Then, the pollen went into the “mixed” container.

5

Dear Henry,

Thank you for caring to warn me about pulmonary risk re Clorox. The undiluted Clorox bottle (narrow opening) is open for just the moment it takes to pour a capful into a pyrex cup. Then it’s immediately diluted 9-fold. I do that a total of 3 times in November. Although I’m old (will be 70 in a week) to my knowledge, my pulmonary system is fine. So I perceive the risk as very low. That said, do you think hydrogen peroxide is at least as effective while also being safer?

6

Regarding the use of Clorox. You store the bags containing the chlorox solution in a closed fridge. I assume that it slowly passes from the bags into the fridge.

Regarding hydrogen peroxide, if I remember correctly, one of our members long ago reported that it did not help his germination. I felt that he used too high a concentration.

Here is a Google search:

https://www.google.com/search?source=hp&ei=kEHxXpKJNZqytAbF25SABg&q="hydrogen+peroxide"+seed+germination&oq="hydrogen+peroxide"+seed+germination&gs_lcp=CgZwc3ktYWIQAzICCAAyBggAEBYQHjIGCAAQFhAeMgYIABAWEB4yBggAEBYQHjIGCAAQFhAeMgYIABAWEB4yBggAEBYQHjIGCAAQFhAeOgUIABCxAzoFCAAQgwFQuhNYwcYBYJ3VAWgAcAB4AIAB2gGIAd4VkgEGMzQuMS4xmAEAoAEBqgEHZ3dzLXdpeg&sclient=psy-ab&ved=0ahUKEwiSkdO1zJbqAhUaGc0KHcUtBWAQ4dUDCAk&uact=5

7

Henry, the plastic baggies are sealed and the Clorox so dilute and it’s in the crisper section of the fridge, I’m not worried. Thanks though.

8

A thin plastic bag has some permeability.

Bleach does not simply disappear, it could end up as chlorine gas or as:

" Once in the water, bleach reacts with other chemicals to form, among other products, dioxins. Dioxins are known to be highly dangerous toxins that can have serious impacts on health. Bleach also puts wildlife at risk; its byproducts have been linked to cancer in studies on laboratory animals. Environmental toxins created by bleach have lowered the populations of several species of birds and fish.

Bleach is especially damaging to the environment because it lingers for many years. Even small amounts of the toxic chemical can accumulate in air and water over time, which can eventually result in adverse health effects."

9

Marty, thank you for sharing your insights and method. Although I don’t plan to switch over to mixed pollen anytime soon, your ideas are valid and insightful.

By way of comparison, before I became significantly interested in roses, I had a background of some experience with chestnuts. In many cases, chestnut breeders would use bagged pistillate flowers and controlled pollinations. Although controlled pollinations are standard practice, they are obviously time consuming and in chestnuts somewhat dangerous (since chestnut flowers are often so high off the ground). In chestnuts, controlled pollinations are also prone to low seed set, perhaps in part due to a combination of (generally) only 1 pollination attempt and the potential for that pollination not to completely coincide with peak pistillate receptivity.

Robert Leffel, who had retired from the USDA, pioneered the use of chestnut orchards designed for effective crossing without the need for controlled pollinations. He wrote his method up and I had the pleasure of meeting with him one afternoon and discussing his ideas, but stated simply, his method involved the use of mother plants with cytoplasmic male sterility (so the mother plants had non-functional stamens or pollen) and nearby male plants specifically chosen for his breeding goals. With this method, he could know who the mother tree was but not the father tree…but that didn’t matter if all the nearby male-fertile plants had been carefully chosen to align with his breeding goals. In this way he could proceed towards his breeding goal while drastically reducing time spent and maintaining a high degree of genetic diversity in his population.

Point being that depending upon your goals, it is possible to significantly reduce time expenditure on the pollination or record-keeping steps (or both). Thanks Marty for sharing your insightful ideas on this.

Regards,
Matt Lustig

10

Henry, thanks to you, in an abundance of caution, I’ll use heavier freezer bags with quailty seals to store the seeds for the 4-6 weeks they’ll be in that closed crisper section of the fridge. Somehow though, I think something else will kill me first.