I have been crossing and doing grow outs with my Japanese Morning Glories since 2006. Anyone can do this. I love growing plants from seeds, doing my own crosses, grow outs and selecting flowers trying to stabilize them to come true from seeds. I am not growing as many as I used to and I do not sell or trade seeds anymore. You don’t necessarily have to do crosses. How about selectively growing your varieties for traits you prefer?
I am not too idealistic about Japanese Morning Glories coming true from seeds. Many different varieties exist and some are more uniform in their genetic makeup. Their stamens are positioned over the pistil in a way they can self quite easily so they will tend to produce more uniform crops of seedlings.
Some Japanese Morning Glory varieties manifest dominant traits like blizzard and ray white but also may not be homozygous having only one gene instead of a pair or two genes that are a little different and therefore can throw offspring lacking the blizzard or ray white.
For example, a blizzard vine may inherit the weaker blizzard gene and have a mostly solid color with a few streaks or it might not inherit the blizzard gene and end up being a solid color. Instead of Fuji No Monet, we get Fuji Not or Fuji No White Ray. Once a vine loses the ray white, the solid flower can`t get it back unless it gets crossed with another ray white. If one desires all the vines to be ray white then it is best to cull out the solid blooms and tie blooms on the ray white blooms then test grow the seeds for conformity to type.
Then we hear complaints about the seller who is not responsible for what happened when the genes recombined in the seeds. Instead of Sazanami, we get Sazanami Not. If a bee spreads pollen from Mount Fuji onto the Sazanami then we might get a weird Sazanami sporting the ray white of the pollen parent. The worst thing that can happen is a bee lands on a large flower and then spreads the pollen to a kikyozaki that may be low pollen that day. The result is a medium sized rounded flower. In open pollinated batches of kikyozaki grown in the open garden, I always find at least one round flower in 12 seedlings. Sometimes I get 100% true in a batch of 8 seeds but the more plants you grow the more you tend to see what really happens.
We also have recessive hidden genes that affect the flower which can appear as a surprise. The chocolate becomes “rose” or a dilution of the original color. The “red aka dark pink” becomes just pink. The recessive genes take time and patience to cull out but they are advantageous in that a recessive will be more likely to come true from seeds if selfed.
The best way a seller can ensure their buyers know what they are getting is to test the batches of seeds, take pictures and sell them as what is represented by the test grow results. One solution to help increase conformity and stop cross-pollination is to tie blooms but this is not foolproof. I still have to keep the vines culled out and properly selected if I want to achieve a certain bloom shape, color or vine habit.
For now, I only grow a few varieties each year just as part of my usual annual plantings for the splashes of color often much needed in the heat of summer.