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Sci Tech
Foot rot in black pepper
New plants of colubrinum can be easily raised from cuttings or seeds. Seeds have to be fresh while sowing since viability is low.
QUICK WILT is a dreaded disease of spice crop. Resistant varieties, related compatible species or hybrids are used as rootstocks for such purposes. Piper colubrinum Link is one such useful species quite compatible with black pepper as a rootstock. The plant has been found immune to the foot rot causing fungus Phytophthora capsici and resistant to nematodes that cause root knots in black pepper.
Piper colubrinum Link is a shade loving plant growing in marshy habitats and the stem puts forth numerous aerial roots that go and penetrate into the soil. Water stagnation is not detrimental as long as the shoot is above water level. Due to affinity for fresh water, it can be used only with irrigation.
Grafting of black pepper on Piper colubrinum Link was attempted but the survival of the grafts have been poor in the long run. Anatomical studies have shown anomalous thickening at graft union with over growth of black pepper and splitting of stem and formation of a dark layer at the cambial contact region wherever grafts failed.
Attempts at Indian Institute of Species Research Farm, Peruvannamuzhi, Calicut had shown that the grafts could survive nine years with daily irrigation indicating that watering is crucial for survival. It is said that graft can yield many years if managed properly.
New plants of colubrinum can be easily raised from cuttings or seeds. Seeds have to be fresh while sowing since viability is low. Seeds sown in sand germinate readily and after four leaf stage can be transferred to bags filled with any suitable potting mixture.
When cuttings are taken, collect cuttings only from main shoot and avoid lateral branches that bear fruits, since grafts on such shoots tended to fail quickly. Shoots with olive green or dark green colour only should be used and those having yellow, brown or discolouration must be avoided.
Cuttings with three nodes if kept in polybags with any medium will root within a week. Since the plant is shade loving, rootstock materials are to be raised under shade nets or houses with 50 per cent shade and watered daily.
It takes about five months time to reach graftable stage after transplanting of seedlings or planting of cuttings, when a height of 50 cm or above is reached. Grafting at 50 cm height is needed to avoid splashing of soil, debris etc., that contain fungal spores to the pepper vine and also to have more aerial roots growing into the ground.
Several methods of grafting such as cleft (wedge), saddle, splice, tongue, approach, double rootstock and yemma budding were tried with colubrinum rootstock. The best performance was seen with double rootstock method. Shoots taken from runner vines trailing on the ground that arise from mature vines were used as scion. Each scion consisted of either a node with leaf or 2-3 nodes without leaves.
Where leaves are retained covering the scion with polybags to prevent drying is essential. Ideal time for grafting is during rains. It can be done with provision of humidity by way of sprinklers, etc., throughout the year. Sprouting is observed 20 days after grafting and the union is complete after three months when the plastic wrapping around graft union can be removed. Single nodded scions take more time for sprouting. While grafting, tender portion of rootstock should be removed and grafting is done at the semi-nature portion. Or the graft will break at the nodes. Fruiting lateral branches of black pepper can be grafted on colubrinum rootstock to get bush pepper plants.
At IISR farm successful grafts were established and are being monitored. Most of the grafts have come to bearing by third year. These are planted at 3 m spacing on concrete poles. However, these grafts can be planted using live standards such as Erythrina indica, silver oak etc. A pit is taken filled with 5 kg FYM or compost and soil at planting. No further digging is done since the root system is peripheral.
All roots coming out of the nodes are allowed to penetrate the ground for anchorage and better nutrient uptake. Manures and fertilizers are applied to the base after hand removal of weeds and raked into the soil without digging and mulching is done with 15 kg of green leaves in June and September.
A manurial schedule of 10 kg FYM/ compost 230 g urea, 250 g super phosphate or 200 g mussoriefos and 240 g muriate of potash are applied per year for a 3 year old vine in split doses.
Neem cake has been found detrimental and need not be used. No bordeaux mixture application or any nematicides are required for plant protection. Pollu beetle can be controlled with endosulfan at 1.5 ml/litre applied in June and August/ September.
Suckers that arise may be grafted with pepper and allowed to grow or removed. As the vines grow these need to be tied to the support periodically. Shade regulation is to be practised to provide 50 per cent shade to the vines. Irrigation can be given by micro sprinklers, basin method or drip to provide 15 litre water per day per vine and 7 litre for bush pepper plants.
To each plant is applied 20 g urea, 4 g super phosphate and 30 g potash every four months for plants raised on ground. For those growing in pots 2 g urea, 0.5 g super phosphate and 2 g potash can be applied once in two months or 15 g groundnut cake may be give. Bush pepper plants are to be planted at 2 m x 2 m spacing. These grafts will produce pepper throughout the year.
P. A. Mathew, K. V. Peter
. Calicut-673012, Kerala.
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