Introduction
Pointed gourd (Trichosanthes dioica) is known by diverse vernacular names, parwal, parmal, panal, or patal and has its probable primary center of origin in the Bengal Asom area or Indo-Malayan region. It is a vegetatively propagated, dioecious, and perennial cucurbit vegetable, which is regarded as the King of gourds in India from very early times. The tender fruits which are available for 9 months (February to October) can be consumed as different delicacies like cooked/fried dishes, sweets, and pickles. The newly emerged tender shoots with leaves are also a preferred potherb in many households in India. Fruits may be club-shaped, cylindrical, oval, spindle-shaped or tapering having different sizes, colors and striation, commonly found in cultivated varieties. The crop is widely grown in eastern Uttar Pradesh, Bihar, West Bengal, Asom, Odisha, Madhya Pradesh, in some parts of Maharashtra, and Gujarat, and some hilly tracts of Telangana, Andhra Pradesh, and Tamil Nadu.
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Climate and soil
It thrives well under hot or sultry climates but is susceptible to frost and cold. It can withstand water stress, but not water-logging. The abundance of sunshine and fairly high rainfall favor good crop yield. Vine growth becomes highly restricted during winter, which starts again along with sprouting from the fleshy roots at the onset of spring. The optimum temperature for growth and development ranges from 25-35°C. However, the regeneration of new sprouts is generally impaired below 20°C and severe cold (below 5°C) is injurious to the crop. Well-drained sandy loam to loam soil with a pH range of 6-7 is ideally suited for this crop. Heavy soils are not suitable for their cultivation.
Varieties
Pointed gourd based on shape and size can be grouped into 4 major types: plants bearing spindle-shaped fruits, plants bearing oval-shaped fruits, plants bearing nearly cylindrical fruits; and plants bearing small size fruits of different shapes.
Some improved varieties of the pointed gourd are discussed here.
Faizabad Parwal 1: This variety has been developed at NDUAT, Faizabad, and produces very attractive, round, green fruits, the average yield being 15-17 tonnes/ha. It is recommended for commercial cultivation in Uttar Pradesh and adjoining parts of Bihar.
Faizabad Parwal 3: This variety has been developed at NDUAT, Faizabad. Its fruits are spindle-shaped, green, and less striped. They are excellent for culinary purposes. With an average yield of 12.5-15.0 tonnes/ ha, it is suitable for cultivation in eastern and western Uttar Pradesh.
Faizabad Parwal 4: This variety has been developed at NDUAT, Faizabad. It is recommended for reclaimed sodic soils. The fruits are light green, spindle-shaped with tapering ends. It is recommended for a bower system of cultivation.
Rajendra Parwal 1: This variety has been developed at Rajendra Agricultural University, Samastipur. Fruits are long, green with white strips and tapering at both ends. The average fruit weight is 40 g. It has good long-distance transportation quality and is tolerant to fruit flies. It is suitable for cultivation in both diara land and upland areas and has a yield potential of 17.5-19.0 tonnes/ha.
Rajendra Parwal 2: This variety has been developed at Rajendra Agricultural University, Samastipur. Fruits are drum-shaped, whitish-green with very light stripe and soft. The average fruit weight is 30 g. It is tolerant to vine and fruit rot as well as the fruit fly. It is suitable for cultivation in both diara and upland areas and has a yield potential of 16-18 tonnes/ha.
Swarna Alaukik: This variety has been developed through clonal selection at HARP, Ranchi. A high-yielding variety produces light green fruits with blunt ends. The fruits are 5-8 cm long, solid thin-skinned, and good for vegetables as well as for the preparation of sweets. Its average yield is 23-28 tonnes/ha on vertical staking. It is recommended for uplands and plateau regions of Bihar, diara lands of Gangetic belts of Bihar and Uttar Pradesh, and plains of Odisha, West Bengal, and Telangana.
Swarna Rekha: This variety was developed through clonal selection at HARP, Ranchi. It is a vigorously growing, high-yielding variety. Fruits are greenish-white, striped, 8-10 cm long, and tapering at both ends. The average yield is 20-23 tonnes/ha on the vertical bower system. Recommended for commercial cultivation in plains of Odisha, plateau region of Bihar, diara lands. and plains of Bihar and Uttar Pradesh, and Telangana.
Propagation
It is vegetatively propagated through the vine and tuberous root cuttings. The seed (recalcitrant type) is not recommended as commercial propagating material because of poor seed viability, germinability, production of about 50% of male plants, and late flowering. Mostly cuttings from one-year-old mature vines are taken in October, when fruiting is almost over, to ensure the sex and variety to be planted. Collect 60 cm long vine having 8 to 10 nodes and make it into a coil. Treat the nodal portion of the coil with the rooting hormone. Insert the treated portion of the coil in polythene bags filled with a potting mixture containing the same proportion of soil, sand, and vermicompost. Apply water with rose can sparingly and put them in shade or plastic-house. Sprouting can be seen from 10 to 12 days onwards. These cuttings can be transplanted in the main field after 2 months. This method produces a large number of plants of one variety in one place. Tuberous roots from the mature vine can also be planted on mounds in the main field and watering is necessary as and when required till it produces new sprouts.
Cultivation
Land preparation
Raised beds 15-20 cm high with 1.2 m width and convenient length are prepared in conventional manner. A spacing of 50-60 cm is maintained between two beds, which serves the irrigation-cum-drainage channel. Mounds are prepared on both sides at 1.0 m spacing in raised bed system and on the middle at 75 cm spacing in bower system. Mounds in different systems of planting are prepared with the mixture of 15-20 tonnes of FYM/ha and require basal dose of fertilizers.
Planting time
Early planting (late August to mid September) can be done in upland situation but it is not beneficial in medium land situation as frequent heavy downpour hampers establishment of the cuttings while, planting of the vines after the onset of winter delays sprouting and establishment of the plants. First week to second week of October is ideal planting time in high rainfall areas, and late October to November in diara lands. Low lying areas, usually flooded by overflowing rivers in the rainy season, are covered by its summer crop. The crop can be forced during harsh winter (November to February) in Diara lands in Uttar Pradesh and Bihar by planting of rooted vine cuttings in sand of riverbeds with required watering till they drive roots upto the groundwater level. Such moisture laden sandy beds get warmed up quickly and wipe low temperature effect of the winter.
Planting density
In bower system, nearly 7,000 cuttings are required to raise 1 ha crop with a spacing of 2.0 mx 0.75 m, whereas in raised bed system, 16,500 to 17,000 cuttings are required spaced at 1.0 m x 0.6 m. Nearly, 2,500-3,000 cuttings are required to raise a healthy crop with a spacing of 2 mx 2 m in 1 ha under riverbed cultivation.
Planting methods
Planting methods are discussed here.
(i) Vine cutting: The defoliated vine cuttings after dipping for 6 has a preventive measure against root-knot nematode (Meloidogyne incognita) are to be planted in the field following different methods:
(a) Lunda or lachhi method: In this system, mature vines of 1.0-1.5 m long having 8-10 nodes are taken and folded into a figure of ‘8’ commonly known as lunda or lachhi. This should be placed flat in the pit and pressed 3-5 cm deep in the middle into the soil. To enhance sprouting, fresh cow dung may be applied over the central part of the pit if there is no rain.
(b) Moist lump method: In this method, 60-90 cm long vine is encircled over a lump of moist soil leaving both ends 15 cm free. Such lumps are buried 10 cm deep into the well-prepared pits leaving the ends of the vine above the soil. The undersoil part sticks to the root and the exposed ends give sprouts.
(c) Straight vine method: The vine cuttings are planted end-to-end horizontally 15 cm deep into the furrows. These furrows spaced 2 m apart are opened and filled with a mixture of
(d) farmyard manure. Ring method: The vine cutting is coiled into a spiral or ring shape and planted directly on the mounds, covering half to two-thirds of the ring under the soil. The exposed portion produces new sprouts.
(e) Rooted cutting method: The cuttings from mature vines are planted in the nursery, where they are allowed to strike roots. These cuttings are planted between February and March in eastern Uttar Pradesh and shifted to riverbeds in November.
(ii) Root cuttings: Tuberous roots 8 to 10 cm long and of pencil thickness taken from the matured vine are to be dipped in carbosulfan @ 500 ppm for 6 hr against root-knot nematode and planted on mounds premixed with farmyard manure, neem cake, basal fertilizers, and carbofuran 3G @ 5 g/pit. This can ensure 100% sprouting within 10 to 15 days. Propagation by this method is easier and faster. But the availability of roots is a major problem. However, the growing crop over raised bed produces more number roots than bower system.
Pollination management
Undeveloped fruit in the pointed gourd is a common problem due to lack of pollination. In the field, 8 to 10% male plant population is considered enough for getting maximum fruit set. In commercial cultivation, separate raised beds of male clones are maintained. Hand pollination in female flowers is widely practiced nowadays due to the paucity of pollinator population, indiscriminate use of pesticides, and environmental pollution which even results in a 2.5 fold increase in fruit set over natural pollination. Hand pollination must be completed preferably by 5.30 am. Pollens of one male flower are sufficient to effectively pollinate 4-5 female flowers. However, several techniques of artificial pollination like a collection of pollens by hammering with a wooden stick in a glass, diluting with water, sieving using a net, and pollinating female flowers by putting a drop of solution using a dropper. In the rainy season, plucking of male flower buds is done in the afternoon, and they are kept overnight in water, and plants are pollinated in the morning when the weather is favorable. An appreciable percentage of parthenocarpic fruit set occurs in pointed gourd following pollination with the pollens of bitter gourd and bottle gourd.
Manuring and fertilization
Farmyard manure should be applied @ 20-25 tonnes/ha at the preparation of mounds. In September and October planting, apply a general fertilizer dose of 150 kg N, 60 kg P₂O, and 40 kg K₂O/hectare. One-third N along with full P and K fertilizers and farmyard manure should be given as basal and rest N should be top dressed in two split doses, at 90-100 days after planting and the rest, one month later. At late planting (December) after harvesting winter rice, half of the nitrogen and a full dose of phosphatic and potassic fertilizers are to be applied as basal, and the rest half of the nitrogen is side dressed 110-120 days after planting. Excessive nitrogen under frequent irrigation promotes excessive vegetative growth, especially in heavy soils which reduce the propensity of flowering in both male and female plants. For ratoon crop, NPK mixture with well-rotten farmyard manure is applied by loosening the soil around the mound towards the end of winter, or before the start of fruiting every year.
Training and pruning
This crop can be grown by training the vines over low trellises or bowers of 100 cm height, made up of bamboos and wires. The planting distance is reduced to 2.0 m x 0.75 m to accommodate more plants per unit area. This system facilitates effective pollination, increasing fruit set, improving appearance and size of fruit, longer availability of fruits, less incidence of disease particularly vine and fruit rot, and increased yield than trailing over the ground.
In ratoon cropping, the pruning of vines helps to increase the fruit yield. During winter the growth of meristematic tissue is retarded to a great extent. Therefore, the vines should be pruned 15 cm from the ground before the winter (October to November) sets in followed by fertilizer application.
Interculture
Hoeing should be done around the root zone to ensure proper growth of the vines at regular intervals. Mulching with paddy straw, water hyacinth, sugarcane trash, dried grass, and sawdust up to 8-10 cm thickness or black polythene (50µ thickness) immediately after planting on mounds helps to conserve moisture, suppress weeds, and protect the fruits from rotting on contact with wet soil. Pointed gourds grown on raised beds are intercropped with different vegetable crops, like beet leaf, radish, coriander, fenugreek, cauliflower, cabbage, pea, etc. during early stages of growth (October to January) for better land use and greater economic return. However, the success of the companion crop largely depends on proper weeding.
Irrigation
Irrigate the field once in 8-10 days in summer whereas 25-30 days in winter. During the rainy season, irrigation is generally not required. Frequent irrigations also promote excessive vegetative growth, especially in heavy soils. Irrigation water should be restricted to the base of the plant or root zone without wetting the vines. Frequent wetting of stems leaves and developing fruits promote rotting disease of the vines and fruit.
Diseases and pests
Vine rot or fruit rot: This disease is caused by Pythium spp. and Phytophthora is mostly seen in the rainy season, especially when water stagnation occurs. The tender shoots, leaves, and fruits show white cottony growth. The other soil-borne fungus, Macrophomina phaseolina, causing collar rot to attack the root and collar region of the vines and the affected portion gradually rot and finally drys. This disease becomes rampant in the crop preceded by jute.
Downy mildew: This disease is caused by Pseudoperonospora cubensis and is prevalent in high humidity, especially when summer rains occur regularly. Yellow, more or less angular spots on the upper surface of the leaves, white-purplish spores appear on the upper surface of the leaves. The disease spreads rapidly, killing the plant due to defoliation.
Fruit fly: Most serious and destructive insect of the pointed gourd is (Dacus dorsalis). On hatching, the maggots feed inside the fruits and infested fruits can be identified by the presence of resinous liquid which oozes out of the punctures made by the flies for oviposition. The infested fruits start rotting due to secondary infection of micro-organisms. Root-knot nematode: Root-knot nematodes Meloidogyne incognita incites profuse galls on roots resulting in deformation of the entire root system and hamper in the supply of food and water inside the plant system. In a severe attack, the growth remains stunted and plants die with the secondary attack of soil-borne pathogens resulting in complete crop loss.
Harvesting and post-harvest management
Harvesting generally starts 90-120 days after planting. In October planted crop of West Bengal, harvesting of fruits generally starts from the middle of February and reaches at its peak during June-July and continues up to September. Harvesting should be done at the tender fruits stage. Generally, fruit attains marketable maturity in 11-13 days after the fruit set. Picking should be done frequently. Delay in harvesting causes the formation of mature seeds in the fruit. The fruit yield varies from 10-60 tonnes/ha depending on the cultivar, time of planting, crop husbandry, training on trellises, pollination management, and ratooning. Fruit yield increases subsequently second year onwards and declines fourth year onwards.
Fruits remain marketable for 3-5 days under ordinary storage conditions. After harvesting, placing of fruit in cold water (10°C) sanitized with sodium hypochlorite solution (100 mg/liter) for 20 min, and then dipping in Carnauba wax solution (1 part wax + 10 part water) for 60 sec is very effective for increasing shelf-life. Fruit dipping in 250 ppm sodium benzoate or 100 ppm citric acid solution for 10 min extends the shelf-life of fruits up to eight days. Dipping of freshly harvested tender fruits in the solution of growth substances, like kinetin (50 ppm), GA, (20 ppm), CCC (100 ppm), or NAA (20 ppm) for 10 min also increases the shelf life of the fruits up to 8 days without shrinkage and yellowing. Fruits packed in 1 kg capacity polyethylene bag remain fresh for up to 25 days at 8°C and 90% relative humidity. Fruits are packed in baskets or gunny bags for sending to the market in a crude way. Pointed gourd must be collected in plastic crates while harvesting and packed in CFB boxes and staked properly in trucks during transit.
