Spices and Condiments

Pruning

 
• The height of the vines should be restricted to facilitate hand-pollination and harvesting. Care should be taken not to tear or bruise the leaves, branches or roots of the plant. The top 7.5-10 cm of the vine is pinched off 6-8 months before the flowering season to encourage the production of inflorescence in the vines.
• The vanilla flower has a peculiar morphology. The pollen sacs of the flower are covered by a hood-like structure called 'anther cap', and the stigma is actually prevented from coming into contact with stamens due to the presence of a lip-like projection called the labellum or rostellum.
• Because of this separation, self-pollination of the individual flower is impossible. In Mexico, natural pollination is effected by bees of the genus Melapona and hummingbirds, but in the absence of those pollinators in our local conditions, hand-pollination is the only alternative.
• While doing hand-pollination, a contact between the stigma and stamens is brought about by lifting the rostellum and tilting the anther cap by means of a small bamboo splinter, the size of a tooth pick. A trained person can complete pollination of about 1200-2000 flowers per day.
• V fragrans usually flowers only once a year over a period of about two months, starting from the third year after planting. The flowers open from the base of the raceme upwards and usually one, or more rarely two or three flowers, are open on the inflorescence at the same time. The flowers open early in the morning and remain receptive for eight hours and wither away within 2-3 days if pollination and fertilisation do not take place successfully. The fruit set is highest (97.5-100%) when pollination is done early on a bright morning (6 a.m.-1 p.m.), following a shower of rain. When a fertile cross-pollinated seed is required, it is necessary to obtain pollen from another plant. Usually on vigorous plants, 8-10 flowers in 10-12 inflorescences are pollinated, of which 4-8 capsules are allowed to grow to maturity on each raceme. When the desired number of fruits have set, the remaining buds are removed by clipping off the tip of the inflorescence. All the damaged and malformed capsules are removed during growth. The final number of beans per vine varies greatly and is usually between 30 and 150.
• It has been found that growth regulators like 2,4-D, IAA and IBA will induce the development of parthenocarpic fruits and give a higher Percentage of fruit set.

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