Tropical & Subtropical Fruits

Pruning

The grapevine is a vigorous climber. If it is not properly trained and pruned, it does not bear fruit properly. Pruning is one of the most important operations in grape culture.
The objectives of pruning are as follows:

1. To reduce the amount of old wood in order to keep the vine within manageable limits.
2. To secure fruit bearing branches in predetermined places.
3. To expose the fruiting branches to sufficient sunshine. 4. To reduce the excessive vegetative growth.

It is essential that one should be familiar with the various parts of the vine and their functions for successful pruning. The following are some of the technical terms used:

• Shoot: Young growth of green stem of the current season, which bears the grape cluster.
• Cane: A well mature and ripened shoot of the past season or that of the previous year which gives rise to shoots.
• Spur: A portion of the cane or ripened shoot left behind on the plant after pruning.
• Fruiting spur: A cane or well ripened shoot leaving 304 buds, producing a bunch after pruning.
• Foundation spur or Renewal spur: A well-ripened shoot or cane bearing bud. This normally remains after the shoots are pruned in March-April or summer in Hyderabad. It is called a foundation spur as it forms the base of the foundation wood on which next year's canes and fruiting spurs are formed or on which both growth of the year are borne.
• Trunk: Main stem of the plant.
• Long spur: A ripe shoot, carrying more than five buds. Normally it is 25-30 cm long with about 5-10 buds on it.
• Medium spur: It is a cane cut back keeping 3-5 buds.
• Spur: It is cane pruned to 1-2 buds.
In India, being a tropical country, there is a marked apical dominance of growth of the vine, because of the failure of the most of the buds to sprout and grow after the pruning. On the other hand, in temperate zones the Thompson Seedless when pruned to 15 buds, there is 60 to 100 per cent bud burst as against 6-9 per cent in India. Therefore, the stimulus nearby pruning wound is the important factor in forcing bud burst. Usually the only bud that may grow on a long cane of 6 to 15 buds is the bud left in the terminal position. This factor of extremely low frequency of bud burst confined almost entirely to the terminal position. The tendency of only the terminal buds to grow on the pruned canes has an important bearing on the form and eventually the cropping and longevity of the vine.
The problem of rapid elongation of the arms or other more permanent frame work of vine is of course most acute when one is forced to leave long canes to ensure that enough crop will be obtained, such as is necessary in Anab-e-Sliahi and to a greater degree in Thompson Seedless. In varieties such as Muscat Hamburg or Perlette, where the basal buds are often fruitful than that pruning will ordinarily not present this difficulty.