Learning how to manage a cocoa plantation
Posted on September 12, 2012
The last few weeks of my cocoa trail are spent at the Ecuadorean government’s agricultural research institute INIAP, an acronym which stands for Instituto Nacional de Investigaciones Agropecuarias.
INIAP was founded in 1959 to find ways of improving sustainability and production levels in agriculture and livestock farming. There are seven INIAP research centres covering different crops and regions across Ecuador.
I am fortunate to have the opportunity to spend a couple of weeks working in the cacao department. INIAP’s experts are dedicated to improving and developing quality cacao and their research covers everything from genetic clones to the production and tasting of the best cacao beans.
It is an honour to be surrounded by such knowledgeable people. Finally I can get answers to the many questions that have arisen in my mind during four and a half months in the field.
At INIAP, in addition to spending time in the quality-control laboratories making cacao liquor and chocolate from the nacional beans, I learn how to pollinate, graft and prune cacao trees.
Like other fruit trees, cacao trees can be reproduced in various ways. The most natural way is through pollination and planting beans straight from their pods into fertile soil.
However, in order to improve the genetics of certain cacao types it is common practice to “graft” the trees, a process known in Spanish as “injertar”. Grafting, in cacao, is used to improve the quality of the pods, the tree’s productivity levels and its resistance to diseases.
As I learn how to graft, the first thing I need do is select a tree from which I shall take a leaf bud, called a “yema” in Spanish, which will then be grafted onto the receiving tree, called the “patrón”, or master in English. The recipient tree, also known as rootstock , has grown freely from seed. The tree from which I will take the leaf bud is a clone that has been developed to produce beans of high quality and with high productivity.
Once the leaf bud has been selected, I need to cut the end of its stem. This takes hours of practice, as to achieve a finely cut end is far from easy. I finally succeed in cutting the stem to the required degree of fineness on my second day of trying.
I then need to delicately cut the main branch of the “patrón”, so that I can carefully insert the finely cut tip of the leaf bud’s stem into the newly formed slit.
Finally, I carefully wrap the joined branches with plastic cling foil, to protect the graft. If all goes well, it takes about twenty days for the leaf bud to begin to develop on to the branch and grow as one.
Once the tree is mature, the “patrón”’s original main branch is cut off above the graft, and what was the “yema” now becomes the main trunk.
Another technique which I learn is artificial pollination. Flowers can be naturally pollinated by the wind, but the most common way for pollination to occur is through insects that transport the pollen to the flowers. In the case of cacao trees, very small flies or midges are responsible for pollenating the cacao flowers.
These midges, called “Forcipomiya”, are invisible to the human eye. They live in the leaves below the cacao trees, and this is one reason why the use of pesticides must be avoided in the cultivation of cacao.
Artificial pollination is generally undertaken to increase the fecundation levels of the flowers, and hence the number of pods produced, but also to improve the tree’s own cacao variety. In our case, we are conducting pollination to check whether the trees in the cacao field are compatible with a clone that is about to be introduced. We need to ensure that the two types of trees will be able reproduce amongst themselves.
Observing the flowers of the cacao tree, I note how they are all grouped together along the branches and trunk of the tree. I am told that the flower of the cacao tree is “hermafrodita”, or hermaphrodite: it possesses both female and male organs.
The male organ is formed by stamens which are the pollen-producing reproductive organs of the flower. Each flower has five stamens. The pollen is located at the head of each stamen.
The female organ is the pistil formed by the stigma, the style and the ovary. As the pollen falls on to the stigma, it goes through the style to the ovary.
As fecundation begins to take place, a baby cacao pod begins to grow. It will take 150 to 180 days for the pod to reach maturity.
To begin the artificial pollination, we first select a mother tree whose flowers are to be pollinated. Then we look for flowers whose petals are only slightly open and look slightly swollen, to ensure that they have not already been pollinated naturally. These will be our “mother” flowers.
Once each flower has been selected we carefully cover it with a tube overnight to protect from being naturally pollenated while still allowing it to open up.
The next morning, we come to check the flowers, and indeed the petals have now opened. Carefully pushing back the petals, I remove the stamens of a mother flower in order to facilitate the pollen’s access to the stigma of the flower. It takes a lot of concentration and precision!
We then pick a “father” flower from another tree, and with tweezers we carefully remove the sepal to facilitate the contact of the pollen with the mother flower.
We bring the “father” flower to the “mother” flower, so that the pollen makes contact with the stigma, where the pollen will pass down the style through to the ovary.
Since the mother flower is quite delicate we cover it with a tube to protect it from the wind and insects.
Four days later we return to see if the flower has fecundated. I am happy to say that the trees are compatible and my pollination techniques were a success!