Open bean flower, ready for pollination
From Asturias in northern Spain, I got a nice tasty big white dry pole bean. But it’s a bit late, and for that reason not prolific in my garden. I’ve tried three varieties of this Asturian bean, none of them full-fill my wishes. Two of them I had sent directly from a gardener in Asturias. It’s the earliest varieties they have in Asturias.
The only way ahead is to breed my own pole bean of this type.
Bean Fabada da Asturias
Fabada da Asturias was the first pole bean of this type that I tried in my garden. I got it from Gerhard Bohl, Germany. Since I had Andecha, which is also a pole bean, with even bigger white seeds, from Anselmo in Asturias.
What cultivars should I cross them with? It should of course be an early bean, as the only thing I’m unhappy with is that they are late maturing.
An obvious choice could be an early bush bean, but I want a pole bean. Pole beans yield so much more than bush beans. In my garden, I can easily find poles to support the beans.
Therefore I will cross to early maturing pole beans that do well in my garden.
Bean Carré de Caen
Pole bean Carré de Caen proved to do well in the wet summer last year. It grew, flourished and set lots of beans almost endlessly. It has some similarity to the Asturian beans, being white and delicious, but the beans are very small. This I will use for crossing.
Pole bean Chabarovsk grows really well in my garden, and is the first pole bean to ripen dry beans every year. It is a borlotto-type, but because of its earliness I will use it for crossing.
Normally beans self-pollinate before the flower opens. Therefore I have to pollinate before the flower opens. But when? I looked it up in Carop Deppes book “Breed Your Own Vegetable Varieties”. She is not sure, but suggest beans behave like peas in this matter. Mother-plant flower must be quite undeveloped and small. Father-plant flower opened naturally the same day.
Both stigma and stamens are tightly wrapped in a conch-like spiral of the lower petals, the keel. As long as the stigma and stamens are sitting inside the keel, it is impossible to cross them. The keel has to be removed. I ruined three flowers learning how to do it. The conch-like keel is visible in the second image from the top (Fabada da Asturias). In the top image the keel has been twisted out of the keel.
Of course it is even more difficult with the mother-plant’s flowers, because they must remain on the plant. I pulled accidentally the flower of the plant several times – that makes no good cross. But even that I learned.
Bean flower stigmas hooked together
First the father-flower is prepared, since pollen is more robust than the stigma. Pollen is able to withstand a trip around the neighbourhood in bodily hairs on a bee! When both flowers are ready, there are several possibilities. Either the usual hand pollination, transferring the pollen directly from the stamens to the stigmas. In beans, usually self-pollinating, it’s possible use the pollen attached to the father-flower’s stigma. Stigmas ends in a spiral, so they readily hook together. I wonder if the pollen is released as the father-flower’s stigma dry out and wilt? Carol Deppe writes, that this hooking method is significantly more successful than the usual hand pollination. I played safe, used the stamens as brushes to paint a miniature of yellow on the stigma, before I hooked up the two stigmas.
The pollinated bean flowers
A: Carré de Caen x Andecha
C: Andecha x Chabarowsk
F: Chabarowsk x Fabada da Asturias
To protect the stigma and style from drying out in the summer sun, I put masking tape around. Note that the tape adheres to the remnants of the petals, but don’t touch the sepals. The tape hopefully come off along with the petals when the pod grows lengthwise. If the tape is adhering to the sepals, the tender pods may break when growing. Another bit of masking tape is sitting on the pedicel so it does not fall off with the flower. It must indicate that this flower is crossed. Finally, I write a letter with a waterproof pen on the pedicel tape, and break of any older flowers in the same cluster, so they do not take the all energy resulting in the abortion of my cross.
Now I can just wait and pray, and hope to see the pod develop in a week or so. Nothing more to do before harvest.