by Karl K » Sat Apr 13, 2019 12:50 pm
Years ago I found that 'Blush Noisette' never set hips unless I pollinated the flowers by hand. Those little petals covered the stigmas, and most of the stamens.
The excessively double
Rosa roxburghii can be pollinated by hand (as I learned by experience) but a bumblebee I once saw visiting such a flower walked around for a little while then flew away in disgust (I'm guessing).
Hybrids and their derivatives can be puzzling. Burbank wrote about an Amaryllis that seemed sterile, but the stigma became receptive only after the petals were fading. Then there was the bigeneric wheat hybrid that was fertile only within a narrow range of temperatures.
Rhododendrons and some of their kin seem to have a time-window that opens when the pollen tubes begin to grow. If they reach the ovary too soon or too late, pollination fails. And in one group of species, those with long styles have fast growing pollen tubes. Species with short styles have slow moving pollen tubes. This keeps the species isolated ... unless someone pollinates repeatedly.
Then there are the complicating matters of soil chemistry, air temperature, humidity, and so on.
Did you know that mango trees can thrive in regions with constant high humidity, but refuse to fruit? Most varieties need a period of relatively dry air to be fruitful. Likewise, for avocados.
http://bulbnrose.x10.mx/Heredity/CollinsMango1903.html
http://bulbnrose.x10.mx/Heredity/Collin ... o1905.html
Years ago I found that 'Blush Noisette' never set hips unless I pollinated the flowers by hand. Those little petals covered the stigmas, and most of the stamens.
The excessively double [i]Rosa roxburghii[/i] can be pollinated by hand (as I learned by experience) but a bumblebee I once saw visiting such a flower walked around for a little while then flew away in disgust (I'm guessing).
Hybrids and their derivatives can be puzzling. Burbank wrote about an Amaryllis that seemed sterile, but the stigma became receptive only after the petals were fading. Then there was the bigeneric wheat hybrid that was fertile only within a narrow range of temperatures.
Rhododendrons and some of their kin seem to have a time-window that opens when the pollen tubes begin to grow. If they reach the ovary too soon or too late, pollination fails. And in one group of species, those with long styles have fast growing pollen tubes. Species with short styles have slow moving pollen tubes. This keeps the species isolated ... unless someone pollinates repeatedly.
Then there are the complicating matters of soil chemistry, air temperature, humidity, and so on.
Did you know that mango trees can thrive in regions with constant high humidity, but refuse to fruit? Most varieties need a period of relatively dry air to be fruitful. Likewise, for avocados.
http://bulbnrose.x10.mx/Heredity/CollinsMango1903.html
http://bulbnrose.x10.mx/Heredity/CollinsAvocado1905.html