Propagation by seedlings

Selection of mother trees: Locate mother trees that give a steady annual yield with a mean fruit weight of 200-275 g, high acid and low tannin content. Collect seeds from freshly harvested and fully ripe fruits and wash in running water and spread in a thin layer under roof. By the 20th day, seeds will be ready for sowing. Sow seeds at the rate of two per bag in polybags during the month of August-September. Usually seeds start sprouting in the month of December but the sprouts become visible above the soil surface only by February. In order to avoid delayed germination, simple seed treatment methods can be employed.

Method 1: In this method, the processed seeds (after drying under shade) are given a mechanical treatment. Remove seed coats of such seeds using a sharp knife without injuring the ivory coloured cotyledon. Sow these ivory coloured cotyledons afresh in polybags at a depth of 3 cm. Germination starts in 20-25 days after sowing.

Method 2: After removing the seed coats, treat the seeds with gibberellic acid @ 250 ppm for 6 hours, and thereafter soak them in mancozeb @ 4 g/l for 2 hours. Sow the seeds in nursery bags and irrigate daily. Seeds germinate in 16-20 days.

Method 3: Second method followed by transfer of the seeds to a white polypropylene cover of size 20 cm x 25 cm along with 30-50 ml of filtered water. Tie the polybag along with the air inside tightly using a rubber band. Such seeds germinate in 10-12 days after sowing. In a polybag, about 500-750 seeds can be incubated at a time. Pick up the sprouted seeds and sow in the nursery bags kept under shade.

Keep the seedlings under shade. Irrigate them regularly on alternate days during summer months. After 3-4 months, place the seedlings under direct sunlight to trigger robust growth. At this age, apply FYM @ 50 g per bag. In six to seven months time, seedlings will be ready for planting.

Propagation by grafting
Two types of grafting methods are employed viz. soft wood grafting and approach grafting.
Soft wood grafting
Select scions only from specific elite trees regular in bearing, which produce high yield of large and quality fruits.

Collection of scion: Select straight growing, healthy, young shoots emerging from the primary branches with whorled leaf arrangement. Cut them to a length of 6-10 cm and store in polybags under humid condition. Remove leaves partly and shape the cut end to a wedge of 3-4 cm length by giving slanting cuts on two opposite sides.

Preparation of rootstock: Stock-plants having 3-4 mm stem thickness are ideal for grafting. Behead the selected plants at two nodes below the terminal bud and remove all the leaves at the graft union. Use scion and rootstock of same thickness for grafting.

Grafting: Insert the wedge of the scion into the cleft made on the rootstock and secure the graft joint firmly with a black polythene tape, 1.5-2 cm wide and 30 cm long.

Care in the nursery: Immediately after grafting, cover the plants with a transparent polypropylene cover and keep under shade. By the 30th day, grafts will establish and new leaves will start emerging. Remove the polythene cover and keep under shade. Water the grafts daily using rose-can or micro-sprinkler. Care should be taken to remove sprouts emerging from rootstock at frequent intervals. Three months after grafting the plants will be ready for planting in the main field. Just before planting in the main field, leave the grafts under open condition in 10-15 days for hardening.

Approach grafting
Here also stock plants having 3-4 mm thickness are preferred and they are brought to the place where the mother tree is located. Grafting is done as in other crops and is kept intact for 45 days by which time union occurs. Graft is detached from the mother tree in three steps. The main disadvantage is that only a limited number of grafts can be produced in this method. Forty-five days after grafting, they will be ready for transferring to the main nursery for hardening. Grafts are to be watered daily using a rose-can or micro-sprinkler. Care should be taken to remove sprouts emerging from rootstock at frequent intervals. Leaf folding pests common in the nursery can be controlled by spraying with quinalphos @ 2 ml/l at monthly intervals. One-year-old grafts can be used for field planting.

The plants can be raised as a pure crop or as a mixed crop in coconut and arecanut gardens. Take pits of size 0.75 x 0.75 x 0.75 m in hard and laterite soils; 0.50 x 0.50 x 0.50 m in sandy and alluvial soils, at a spacing of 4 m x 4 m for grafts and 7 m x 7 m for seedlings. In slopes of 15% or more, for planting grafts, rows are spaced at 5 to 5.5 m and 3.5 m between trees in a row. For planting seedlings, rows are spaced at 8 to 12 m and at 6 to 8 m for trees in a row. Planting is generally done at the onset of monsoon showers. Under existing coconut plantation of 25 years and above, spacing shall be so adjusted that it should alternate with the palms in the rows. Under Kuttanad conditions, where bunds and channels alternate, planting can be done in between two palms. Fill the pits with topsoil and 5 kg of compost or well-decomposed cattle manure and 10 g of carbaryl 10% dust, to avoid white ant attack, before planting. The graft union shall remain just above the ground level. Provide support to the young plants. One month after planting, gently remove the polythene tape around the graft union.

Management of plantation
Clean the field free of bushes and thick shades. Weed once in three months and mulch the basin with black polythene or dry leaves to avoid drying.
Pruning
Grafts will grow fast from the second year onwards. Give strong support with casuarina poles at this stage. By fifth year, the tree will have 3 to 4 m height. At this stage, height of the plant may be maintained at 3.5 to 4 m and by seventh year at 4 to 4.5 m by pruning.

Seedlings start bearing generally at the age of 10-12 years. Grafts start bearing from the third year onwards and will attain full bearing at the age of 12 to 15 years. Flowering occurs in January-March and fruits mature in July. There are reports of off-season bearers, which bear two times a year, i.e., during January-July and September-February. Mature fruits, which are orange yellow in colour, drop off from the tree. Harvest mature fruits manually before they fall. Immediately after harvest, wash the fruits in running water and separate the fruit rind for processing.