I'm excited this morning.
I have an Ipomoea aquatica 'Kang Kong' plant with a flower opening up, this is a highland white stem form, growing in a paladularium. Meanwhile in the basement under a light next to cacti are some Ipomoea fistulosa and one of them has two glorious blooms wide open this morning and loaded with pollen!
Fistulosa has a faint amazing odor, indescribable and lacks the vine like habit more common with Ipomoea. Aquatica has hollow stems and like the name suggests is associated with water, though the white stem form does grow somewhat upright when planted in the earth.
In fact there are shared derived traits that exist in both the Aquatica and the Fistulosa populations and they are more closely related than they are to many other plants in the same genus.
Ipomoea are reluctant in many cases to hybridize, often having very low success rates for extremely high numbers of pollination attempts. For this reason today techniques like hormone treatments to prevent fruit abscission and cut-style pollination, as well as embryo rescue, are often used to increase the odds of success.
I use colored bits of yarn tied or string with knots like notations and a notebook with a key to record the crosses, in most cases. Sometimes when there are many flowers I just cross pollinate with a paintbrush. Some Ipomoea which are not typically self fertile do set seed this way, but I have yet to sow it and cannot claim that it is actually a cross (yet?).
It is very common for these crosses to take, start to grow a fruit and then abort, and when it is dissected an embryo with differentiated tissue is clearly visible. I have even seen this happen with pollinating some Ipomoea species with some Convolvulus species, but I am not able to culture the embryos as explants to rescue them. This is the most common type of failure in my efforts, not a lack of crossing or a lack of embryo formation, rather the mother plant aborts the fruit. This is why hormone treatments to prevent this and embryo rescue are used to facilitate interspecific hybridization in Ipomoea.
The size and stage that the fruit is aborted by the plants in such cases often varies depending upon the species and sometimes the fruit drops right before it matures, which can be frustrating!
This is year 3 of the project and the failures are numerous, however as that in some cases crosses succeed on the order of one out of every hundred thousand attempts or more, I often repeat the same cross attempts over and over.
Today is the first time I have had a chance to cross pollinate Ipomoea fistulosa and Ipomoea aquatica and even if it fails, which is likely, this will be a learning experience.
Good Morning!
