CaliFlowers said:My weather is seldom over 80°, so seed-set is seldom a real problem, but there are always a few plants which are difficult. This is a compilation of information I've gleaned from old-school hybridizers.
Unfortunately old-school hybridizers are not usually trained scientists or specifically plant biologists. Their actual observations are more or less correct but typically their conclusions about the causes of those observations are not.
I have better luck with the tough customers if I move them under some afternoon shade, and keep them well watered. A saucer helps, and I never let it go dry until the pods are well on their way.
This one is good as high temperatures are harmful to successful pollinations and pod development and different plants may have different temperatures that limit their success. Water stress (not enough) is never good and may cause pod abortion or other problems.
Some hybridizers swear by "starter pollen". With tetraploids, you can use diploid pollen in order to get them started. The dip pods will abort after a week or so, but the process seems to trigger hormones which get the plant "in the mood" for seed making.
This one is unlikely. There is no known plant where scientific research has indicated any possibility of this sort of effect. Nor as far as I know are there any known plant hormones that would alter the seed making ability of the plant in such a way. The most likely reason this may appear to work is if early in the season pollinations are not as successful as pollinations later in the season. A plant biologist has indicated that this appears to be the case with daylilies and I agree. For one thing the weather is different at different times and waiting a week means that will be the case.
Of course, it's hard to know if the starter pollen is doing the job,
Not likely, biologically.
or if, as Marilyn notes, the last few flowers on the scape just tend to set more reliably.
Much more likely.
I have noticed that if a scape has gone without setting pods until the last blossom or two, even if a pod is set, many times the scape will decline, and along with it, the pod.
Yes, unfortunately. Also if many pods are set on a scape the last few may be aborted.
Holding back on nitrogen is supposed to help too. You can fertilize normally early in the season to build plant size, but when scapes start coming, cut the feeding and just give them lots of water.
Not likely. The plant will need nitrogen to store nutrients in the seed.
Another old trick is to break the plant into small divisions in the fall. Small divisions put up small scapes with few buds, but tend to set pods more easily.
Not likely. Only one hybridizer that I know has ever made this comment and there certainly will have been no way that the hybridizer will have eliminated the possibility that in the year this worked the plant would have shown the same fertility without being divided down into small divisions. Biologically the effect would be the opposite - small fans that flowered would be more likely to abort the pods because they were being too stressed by the nutrient demands/requirements of the developing pods/seeds.
You can also push the plants strongly though the early part of the season in order to get rebloom scapes, which tend to be much more fertile than primary scapes. It's as if the plant knows it's going to rebloom, and "saves its energy" for the second set of scapes.
Possible. Different weather and other environmental factors in the first set of flowers developing during the previous year, winter and spring and the rebloom set of flower developing during the spring and summer.
