Acotanc: Specialist Pollination of Blue Gums for Seed Production

Specialist Pollination of Blue Gums for Seed Production

Author: Liz Barbour
E-mail: [email protected]
Organization: Forest Products Commission
Locked Bag 104
Bentley DC WA 6983
Phone: +61 8-93340302
E-mail: [email protected]

A description of new methods worked out to assist in the breeding of improved Western Blue Gums.

My name is Natalie Broadben and I am speaking on behalf of Dr. Liz Barbour.

This project is not in my field, so I apologise if I seem like I don't know what I am talking about.

Rob (Manning) has just basically done my whole presentation--just swap fruit trees for Western Blue gums and seed for fruit, and you have got it all.

I am talking about the controlled pollination of our Western Blue gums. Our initial system was quite tedious. When the trees are ready to flower, we would locate them on the tree and separate the caps, remove the flower and keep it in a petri dish. Then we split the flower, clean out the debris, put one of these tiny little tubes on the stamen, tag it, and leave it for later. What was happening with this system was that the tubes would often abort, fall off, so it wouldn't be any good to us. The tubes were all different sizes because the stamens come in different sizes. Each tag has to be put on the tree and properly recorded, otherwise you will end up with different crosses from different trees. It can be quite fiddly. Later on, once the flowers had been collected, it was put into a sieve and sifted. The pollen falls through the sieve and is collected and put into a vial and kept in the refrigerator.

Dr Barbour wanted to produce on a large scale, so she actually enlisted the help of Rob in getting one of those bee tubes he was talking about. She was thinking about what to do on the whole area. She wanted to do a mass gather of the pollen, just from that one species. If you have an orchard, we have an accelerated orchard with specific species that have been cross-pollinated, so they are a specialised tree. To capture all those manually can take weeks. You have to go out practically all day, because the flowers are continually opening throughout the day. If you want to capture 300 flowers off one tree, you basically have to be out there all day. If you have 200 or 300 trees, it takes a long time, and not all buds are successful.

So, that is where Rob came in. We isolate the tree with a tent. In the back you can see a beehive. Liz had the idea for the bees to collect the pollen with a pollen trap and originally started with a bee hive. With the isolation tent, you are limited to the size of tree that will fit the tent; otherwise, you have to go to the manual process. The tent allows full sunlight for flower development. The size of the beehive has to be in relation to the size of the tent.

You can see Nick sifting pollen through the sieve.

The tent restricts the size of the beehive and also required feeding. As Rob mentioned, if you don't feed the bees they will die. I think that happened in two instances with the beehive. So we had little dead bees everywhere, unfortunately.

This is Denise who actually did this project, shown entering the tent to feed the bees.

Some bees are attracted by the light and they walk through the pollen foot bath before flying off to collect new nectar.

This is one of the tubes. This was designed specifically for our purpose. It is lightweight, easy to handle the bees, smaller population for a confined area, and the tube was modified to include the foot bath.

Liz had DNA tests done by Dr. Margaret Byrne to identify the seeds of the selfed pure species. This shows the different stages of the germination of the seed after pollination by the bees or where it had been done manually. The end result showed that with Rob's nifty little invention there we produced more pollen and gathered more seeds from those trees as well.