Pollination

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Vanilla
Pollination

Flower Structure:

Flowers are large, pale green, bisexual and zygomorphic. The sepals and petals look alike and is commonly called perianth. The lower petal is short, broad and is modified in to a labellum. The lower part of the labellum envelops a central structure called the column (gynostemium).

Pollination:

Natural pollination is completely absent in vanilla under Indian conditions although it is reported to take place in its centre of origin with the help of Melapona bees and humming birds. Artificial pollination by hand is carried out to get commercial set and crop. The method of hand pollination being practiced now was first demonstrated by Charles Morgen in 1841 and was perfected by Edmond Albius. The procedure involved is simple and done easily by children and women.
The flower can be pollinated 8 hours after opening. Mejority of the flowers open early in the morning around 4 A.M. The ideal time for pollination is after sunrise usually 6 A.M. to 1P.M. As hand pollination cost forms nearly 40 percent of the total cost of the cultivation of vanilla, it has to be done effectively and successfully.
One or two and sometimes three flowers in each inflorescence open per day. Flowers bloom from the base of the inflorescence upward and last for a day. A skilled worker can pollinate 800 to 1200 flowers in a day at the rate of 120 to 150 flowers per hour. The fertilized flower develops in to a fruit. Unfertilized flowers wither and fall off within two or three days. To facilitate proper fruit development, normally 8 to 10 flowers per inflorescence and a total of not more than 10 to 12 inflorscences per vine are pollinated.

Fruits:
After successful fertilization of the flower, it will remain on the rachis and start developing into fruit. The flowers drop off in two or three days of if the fertilization is unsuccessful. It is therefore, possible to judge the umber of fruits which have set and discontinue pollination after the desired number of fruit set has been obtained. Normally about 80 to 100 flowers are allowed to set fruit in a well developed vine.
Fruits are commercially known as ‘beans’. They are pendulous, cylindrical and three angled. The fruits start growing after successful fertilization of the flower. The ovary starts elongating rapidly by as much as 2 cm in a week. The elongation of the fruit continues for a period of three to 4 months. The rate of elongation is maximum during the first month after fertilization. The length of the fruit after complete elongation will be around 20cm.