Everything you need to know about bitter gourd cultivation, production and harvest. Learn about:- 1. Introduction to Bitter Gourd 2. Composition and Uses of Bitter Gourd 3. Climate and Soil Required for Cultivation 4. Sowing Time of Seeds 5. Manurial Requirement for Cultivation 6. Irrigation Requirement for Cultivation 7. Intercultural Operations 8. Harvesting and Yielding 9. Cultivated Varieties.
- Introduction to Bitter Gourd
- Composition and Uses of Bitter Gourd
- Climate and Soil Required for Cultivating Bitter Gourd
- Sowing Time of Bitter Gourd Seeds
- Manurial Requirement for Bitter Gourd Cultivation
- Irrigation Requirement for Bitter Gourd Cultivation
- Intercultural Operations of Bitter Gourd
- Harvesting and Yielding of Bitter Gourd
- Cultivated Varieties of Bitter Gourd
1. Introduction to Bitter Gourd:
Bitter gourd is known by different names such as Balsam pear or Bitter cucumber in English, Kerala in Hindi, Gujarati and Punjabi, Karla in Marathi, Kakara kaya in Telugu, Pavakai in Tamil, Agala kayi in Kannada and Pavakka in Malayalam. Being common vegetable it is cultivated extensively all over India. Its young immature bitter fruits are used in various vegetable preparations.
Globally, it is widely grown in India, Indonesia, Malaysia, Singapore, China, Japan, Southeast Asia, tropical Africa, and South America. The cultivation of the crop is very lucrative, especially in south India from where fruits are exported to Gulf and European countries. Some of the leading producer states in India are Uttar Pradesh, Odisha, Maharashtra, Andhra Pradesh, Tamil Nadu, and Kerala.
The genus Momordica is widely distributed in the tropics and subtropics with about 60 species. Three cultivated species, M. charantia (2n = 22), M. dioica and M. cochinchinensis (2n = 28), are widely used as vegetable. Bitter gourd is although perennial but commonly grown as annual crop. Plants develop tuberous storage roots and vigorous herbaceous vines, sometimes as long as 10 m.
Plants are usually monoecious, which bear small yellowish staminate flowers singly on slender peduncles in leaf axils, while pistillate flowers on short pedicel. In general, the staminate flowers appear first often with a male to female flowers ratio of 20-25 : 1. The fruits develop about 10 irregular with longitudinally rounded ridges (tubercles) on warty surface. The fruits are either extra-long (30-60 cm) or long (15-30 cm) and other type is small and oval (5-10 cm) in shape.
The original home of bitter gourd is not known except that it is a native of the tropics. However, it is considered a native of tropical Asia, particularly eastern India, where its cultivation as a food crop and for folk medicines has a long history, and southern China.
Bitter gourd fruits are good source of vitamin C, and also provide a fair amount of pro-vitamin A, phosphorus, and iron. Vine tips are considered an excellent source of pro-vitamin A, and a fair source of protein, thiamin, and vitamin C. It also contains substantial amount of minerals like calcium, phosphorous, iron, copper, and potassium. The nutritional composition of small and large fruited bitter gourd is given below in Table 7.1.
Bitter gourd is grown for its bitter tender fruits that are used as cooked vegetable or pickle. The fruits are cooked in many ways but more commonly used as fried, boiled, stuffed, and cooked. Tender shoots and leaves are also eaten like green vegetables after parboiling and leaching out the bitter alkaloid. Steeping the peeled fruit in salt water before cooking can reduce its bitterness. The seeds of the ripe fruit are used as a condiment in kitchens of India. Bitter gourd is not advocated for use to pregnant or nursing women.
Bitter gourd contains an array of biologically active plant chemicals including triterpenes, proteins, and steroids. It has anti-carcinogenic and anti-leukemia properties. A chemical analog of bitter gourd proteins is known to inhibit prostrate tumor growth. Two of the proteins- α- and β- momorcharin have also been reported to inhibit HIV virus in test tube studies. Its fruits are easily digestible and have laxative property.
From the Ayurvedic perspective, bitter gourd is an excellent medicine for balancing cough. It helps in purify blood tissue, enhances digestion, and stimulates the liver. The bitter gourd fruits contain a hypoglycemic or insulin-like product, designated as “plant-insulin”, which has been found highly beneficial in lowering the blood and urine sugar levels. Juice of the fresh leaves is used for the cure of piles.
Bitter gourd is highly beneficial in the treatment of blood disorders, like blood boils, scabies, itching, psoriasis, ringworm, and other fungal diseases. Since ancient times, bitter gourd roots are used as folk medicine for respiratory disorders. Root paste mixed with equal amount of honey or Tulsi leaf juice acts as an excellent medicine for asthma, bronchitis, pharyngitis, colds, and rhinitis. Fresh juice of its leaves is an effective medicine against cholera at an early stage and other types of diarrhea, particularly during summer.
3. Climate and Soil Required for Cultivating Bitter Gourd:
Bitter gourd being a warm season crop grows well in sub-tropical and tropical climates, however, it has a wide range of adaptability, thus, can be grown successfully in regions with comparatively low temperature. The seed germination is optimum at temperature between 25° and 35°C and inhibited at 8° and above 40°C.
At temperatures between 25° and 30°C, the vine growth is normal and yield is good enough, however, the temperature below 18°C causes reduction of vine growth, leading to poor yield. On the contrary, temperature above 36°C leads to less production of female flowers, resulting in poor yield.
The crop can be grown on all types of soil but sandy loam and silt loam soils are most suitable for its higher yield. A well-drained soil rich in organic matter has an additional advantage. The best soil pH for its successful cultivation is 6.5-7.0. Water stagnation at any stage of crop growth is harmful. Incorporating farmyard manure or compost the field is prepared by repeated ploughings (3-4 times).
4. Sowing Time of Bitter Gourd Seeds:
In sub-tropical climate, the crop is mainly grown twice once as spring-summer crop and other as rainy season crop, whereas, in tropical climate, it is cultivated throughout the year. In plain areas, the seeds are sown in January-March for spring-summer and June-July for rainy season crop. In hills, sowing is usually done from April to July. At Coimbatore, Tamil Nadu, September- October is found to be the best time for the sowing of bitter gourd crop.
About 4-5 kg seeds are sufficient for the sowing of one hectare, however, the exact quantity of seed required for sowing a unit area depends on its viability and germinability, which are as usual influenced by fruit maturity, time of fruit harvesting, insect injury, and hardiness of the seed coat. The best quality seed with high viability can be obtained from fully ripened fruits of the first flush.
Bitter gourd requires high temperature (between 25° and 28°C) for its successful seed germination. Low emergence of seedlings is, therefore, a common problem at sub-optimal temperature (20°C and below). Its hard seed coat also causes hindrance in its germination. Seed soaking in warm water and seed priming have been found effective for seedlings emergence.
Soaking the seeds in water at 50°C for 60 minute, and then, air- drying to the original moisture level can achieve warm water treatment. Priming, which can be done by mixing seeds with moist vermiculite, incubating at 25°C for 36 hour, and then, air-drying to the original moisture level offers an effective means for counteracting sub-optimal temperature induced oxidative injury and raising seed performance.
Priming can also be done by moistening the seeds in 1-10 mg/litre solutions of sodium selenite and keeping seeds at 25°C for 48 hour, and then, air-drying. Priming enhanced the free radical and peroxide-scavenging activities linked to the ascorbate-glutathione cycle.
Soaking of seeds in water or buttermilk also promotes germination. Increase in seed germination percentage and vigor can also be achieved by seed treatment in 1% KNO3 solution for 12 hour. Providing seed treatment with 25 or 50 ppm GA3 and 25 ppm boron Singh et al. (1973) achieved good germination of bitter gourd. Nath et al. (1972) studied the interaction of light and growth regulators on germination of seeds.
Soaking seeds of Long Green cultivar in 50 ppm solution of GA3 for 12 hour under daylight resulted in highest germination (79.5%). Soaking of seeds also in 100 ppm solution of NAA or 50 ppm solution of 2,4-D resulted in 76.3 and 61.9% germination, respectively. The seeds before sowing should also be treated with Thiram/Captan @ 2 g/kg of seeds to avoid fungal infection, especially in rainy season.
Sometimes due to natural calamities, like excess or unwanted rain, hailstorm, or accommodation of previous crops, it is not possible to prepare the main field in time, thus, in such situations, timely nursery may be raised in ½ to 1 kg polyethylene bags under strict supervision and protected conditions. Nursery raising and transplanting technique of bitter gourd is also applied for off-season cultivation to get early harvest.
Bitter gourd is susceptible to extreme cold (below 10°C), therefore, low temperature during winter is a limiting factor for early production of crop in northern plains, however, it is easy to take early crop by raising seedlings in protected nurseries during off-season. Seeds are sown in 100-150 gauge polyethylene bags filled with a mixture of one part garden soil, one part sand, and one part well decomposed organic manure in equal amount.
About 1.0-1.5 g carbofuran per bag is also added in mixture to avoid infestation of red ants, termites, or other pests. At the bottom of bag, 3-4 small holes are also made before filling them with soil mixture. These bags after sowing seeds are placed under protected conditions, inside the polyhouse or under plastic low-tunnels. After 3-4 weeks when the outside temperature becomes favourable, the seedlings are shifted to pits in the main field.
The seedlings are normally transplanted at 3 to 4 true-leaf stage during last week of January or later when danger of frost is over. In this way, bitter gourd can be harvested about one month earlier than the crop raised by seeding directly in the field. In bitter gourd, about 7500 to 8000 seedlings are required for planting in a hectare of land area.
Depending upon season and system of cultivation the various methods of sowing can be adopted. Seeds are sown on raised mounds for rainy season crop and in shallow pits for spring-summer crop. Bitter gourd is usually sown at a spacing of 2.0×1.5 m. However, Nath et al. (1987) recommended a spacing of 1.5-2.5 m row-to-row and 0.6-1.2 m hill- to-hill.
As usual, four seeds are sown per pit but later the weak and unhealthy seedlings are removed, and per pit, only two seedlings are retained for their better growth and development.
The methods of seed sowing adopted in bitter gourd are described below:
Shallow pits of 60x60x45 cm size are dug, and they are left open for 3 weeks before sowing for partial solarization. The pits are filled with a mixture of soil and compost (4-5 kg/pit). A part of fertilizers such as Urea 50-60 g, Single super phosphate 100-120 g, Muriate of potash 80 g and carbofuran 1.5 g per pit are also thoroughly mixed into the soil before sowing seeds, thereafter, the seeds are sown at 2 cm depth in a vertical orientation to attain good seedling emergence and vigour.
This method is commonly practiced for raising cucurbits in riversides. In this method, the circular pits of 60-75 cm diameter and 1.5 m depth (up to clay layer) are dug at distance of about 2.0-2.5 m row to row and 1.0-1.5 m pit to pit. The pits are filled with 10-12 kg farmyard manure, 40 g Urea, 40 g Diammonium phosphate, and 25 g Muriate of potash.
Similarly in trench method, about 60 cm wide trenches are dug at a distance of about 2.0-2.5 m up to a depth of clay layer and filled with a mixture of soil, well rotten farmyard manure @ 10-15 t/ha, and NPK mixture (25 N, 40 P2O5 and 40 kg K2O/ha). The pre-germinated seeds are sown 45-60 cm apart in trenches. Generally, 3 to 4 seeds are sown per hill at a depth of 2-3 cm.
In this method, maintaining 2-3 m spacing between two channels depending upon cultivars 40- 50 cm wide channels are prepared manually or mechanically since the vines are allowed to spread on the raised portion in between channels. Seeds are sown on both the edges of channel at a spacing of about 50 cm. At least three to four seeds are sown per hill, and later only two vigorous seedlings are retained. Generally, sprouted seeds are sown in spring-summer, and thereafter, adequate moisture is maintained until or unless the emergence is completed.
5. Manurial Requirement for Bitter Gourd Cultivation:
The recommendations for manures and fertilizers vary according to soil type and fertility level, thus, different recommendations are available for different locations. Singh (1989) recommended the application of 20-25 t/ha of farmyard manure, 20 kg N, 30 kg P2O5 and 30 kg K2O/ha as basal and 20 kg N/ha as top dressing at flowering and fruiting time.
Rekha and Gopalakrishnan (2001) advocated an integrated approach to realize maximum yield in bitter gourd. They obtained the maximum marketable yield and size of fruits with 20 t of farmyard manure, 2.5 t of poultry manure, fortnightly drenching of 2.5 t of cow dung and a fertilizer dose of NPK 70 : 25 : 25 kg per hectare. Dhesi et al. (1966) recommended 56 kg each of N and P2O5/ha.
Gopalakrishnan et al. (1983) recommended that each pit (2222 pits/ha) might be supplied with 5 kg farmyard manure, 25 g Urea, 80 g Single super phosphate, and 40 g Muriate of potash.
Lingaiah et al. (1988) recommended a combination of 80 : 30 : 10 kg NPK/ha for coastal regions of Karnataka. Similarly, Suresh and Pappiah (1991) recorded the highest yield of bitter gourd cv. MDU-1 with 80 kg N and 30 kg P2O5/ha. Samdyan et al. (1994) obtained the highest flesh weight, dry matter, ascorbic acid, and TSS content in bitter gourd cv. Pusa Do Mausmi with combined use of 50 kg N/ha and Cycocel (250 ppm).
Generally, for an average fertile soil, about 15 t/ha well rotten farmyard manure should be applied during field preparation. Besides, 60 kg N and 30 kg/ha each of P2O5 and K2O are needed. Full dose of phosphorus, potash, and one-third dose of nitrogen are mixed and applied as basal. Rest of the nitrogen is top dressed in two equal splits, i.e., during vine enlargement (about one month after seed sowing) and during flowering and fruiting.
Besides major nutrients, application of micronutrients is also found beneficial in bitter gourd production. Foliar application of zinc at 20 ppm supplemented at 15, 30, 45 and 60 days after sowing significantly improves the total chlorophyll content, chlorophyll ‘a’, soluble protein, ascorbic acid, harvest index and fruit yield.
6. Irrigation Requirement for Bitter Gourd Cultivation:
Bitter gourd requires a steady supply of water since its roots are mostly concentrated at top 60 cm soil layer. The rainy season crop does not require irrigation, except when there is a long dry spell, whereas, spring-summer crop requires frequent irrigation. In summer, the first irrigation should be applied immediately after sowing, and subsequently, at an interval of 2-3 days until flowering.
Later on irrigations are given at an interval of 5-7 days. Vine growth, flowering, and fruit development are the critical stages for irrigation application. Excessive irrigation at maturity is not desirable as it may adversely affect the storability. Pillai (1988) reported that IW/CPE ratio should ideally be maintained at 1. In practice, this requires irrigation at an interval of 3 to 6 days when CPE (cumulative pan evaporation) values reach about 30 mm.
In diara land water may be applied through earthen pitcher of 20-25 liters capacity. In pitcher, 4 holes of 1 mm are made at 5 cm distance from the bottom and buried into the soil up to the brim. Water is filled in pitcher at every 4th day. Distance between pitchers and basins are usually kept 2.5 m, and 3-4 plants are planted around each pitcher.
a. Hoeing and Weeding:
Weeds pose problem during early period of growth, hence, one or two hand weeding and hoeing may ward-off the weeds. Pre-emergence application of pendimethalin or Alachlor (1 kg/ha) or pre-plant incorporation of fluchloralin (1 kg/ha) is beneficial for the control of weeds, but these weedicides may control weeds only for about 30-35 days.
Later if weeds pose problem, one manual weeding may be done to keep the field weed free. In bitter gourd, Leela (1985; 1993) reported that pre-emergence application of fluchloralin at 3.0 kg a.i. or Butachlor at 2.5 kg a.i./ ha controlled the weeds effectively.
Training in bitter gourd has an additional advantage since the crop is viny in nature. If vines are allowed to creep on the ground, yield is reduced nearly 30%. Training of plants on bower or trellis is an effective practice for getting higher yield and uniform quality fruits. Moreover, training of vines on bower system also considerably reduces the population of fruit fly in bitter gourd.
For the preparation of bower, bamboos or cemented, wooden or angle iron poles are used. The height of poles above the soil surface should be about 2.0 m, and it should be buried into the soil up to a depth of 30-40 cm. The distance between poles is usually kept 3.0 m. Each initial pole should be supported with tilted poles. Cress-cross netting with wires is done to make bower.
Bower system in bitter gourd production is very useful in following ways:
i. Per unit area, more plants can be accommodated due to reduced distance between pits (plant to plant).
ii. Intercultural operation and plant protection measures can be easily applied.
iii. Training ensures quality fruit of uniform size.
iv. Rotting of fruits is very much reduced.
v. Harvesting becomes easier.
Growth substances in bitter gourd are mainly used for enhancing seed germination, for modifying sex expression and sex ratio, and for increasing fruit set and early and total yield. Production of male flowers is significantly reduced with the application of 200-600 ppm ethrel, while Saimbhi (1975) observed that single or repeated sprays of ethrel (480 ppm) retarded growth, lowered male and female flowers number and delayed their appearance.
The lower concentrations of ethephon (50-100 ppm) have been found more effective to enhance fruit set. Application of B9 (500-5000 ppm) and CCC (500-2000 ppm) increased the pistillate flower production.
Bisaria (1974) observed that NAA (100 ppm) increased production of female flowers, induced female flowers at early nodes, and reduced the ratio of male: female flowers from 26 : 1 in control to 5 : 1 in sprayed plants. Mangal et al. (1981) reported that spray of CCC (250 or 500 ppm) produced earliest female flowers (49th day) and maximum fruit yield in bitter gourd cv. HK-8.
Use of growth substances coupled with vernalization (soaking of seed in 25-100 ppm NAA, kinetin, ethrel or Morphactin for 24 h and keeping at 5°C for 5-15 days before sowing) increased the ratio of pistillate to staminate flowers. Verma et al. (1984) reported that spray of boron at 4 ppm was most effective in enhancing number of pistillate flowers, fruit weight, and yield as compared to ethrel, MH, GA3, and silver nitrate in Pusa Do Mousami cultivar.
Mulching in bitter gourd not only improves soil water retention and soil temperature but also improves yield and quality of fruits. Besides improving soil organic matter content and soil fertility, mulching also promotes early fruit setting (2-3 weeks). Mulching with materials, like polyethylene film (black, blue or transparent), paddy straw, sugarcane tresses, and dry leaves increases fruit yield and reduces the percentage of unmarketable fruits.
8. Harvesting and Yielding of Bitter Gourd:
Flowering in bitter gourd starts 45-60 days after seed sowing (DAS). Likewise, the first picking starts at 60-70 DAS, depending upon variety, planting season, soil types, and management practices adopted during cultivation. Immature tender fruits are harvested about 2-3 weeks after anthesis. The colour of tender fruit may be light green or dark green or whitish-green, depending upon variety. Regular harvesting at shorter intervals increases the fruit number, and thereby, fruit production. Fruit picking is usually done at 2-3 days interval.
The shelf life of cooked vegetable is comparatively more than the other vegetables. Cucurbitacin, the bitter glucoside, may help in preventing spoilage of cooked vegetable. Post- harvest losses in bitter gourd are recorded to the tune of 23-32%. All the fruits infested with insect-pests or diseases and deformed ones should be sorted out from the lot immediately after harvesting. The harvested fruits cannot be kept fresh for long time, thus, should be sent to the market as soon as possible.
Sprinkling water over the fruits, the fruit freshness can be maintained for some time in the initial stage. Fruits can be packed in polypropylene bag for extending the shelf life. Exposure of fruits to even minute quantity of ethylene can accelerate maturation and quality loss. Bitter gourd should be stored at moderate temperature preferably above 12°C to avoid chilling injury. Fruits can be held safe for 10-12 days at a temperature of 12-15°C.
The fruit yield in bitter gourd varies from 5 to 15 t/ha, depending upon variety, soil fertility, growing season and other inputs, like fertilizers, irrigation, intercultural operations and management of insect-pests and diseases. Katyal (1977) reported a bitter gourd fruit yield of 9-15 t/ha, and Seshadri (1986) reported 6-12 t/ha, whereas, Sen (1992) obtained a fruit yield of 6-8 t/ha. The individual fruit weighs 50-150 g with 10-12 fruits/plant.
9. Cultivated Varieties of Bitter Gourd:
The varieties of bitter gourd vary in size, shape, colour, tubercles character, and bitterness. The market preference for colour, shape, size, and bitterness also varies with locations. The white colour varieties that are less bitter in taste are preferred more in south India. The characteristic bitter taste of its fruits is due to the presence of bitter principle ‘momordicin’.
The descriptions of some improved varieties are given below:
It is developed at Indian Agricultural Research Institute, New Delhi. Fruits are dark-green, and club-like with 7-8 continuous ribs. Each fruit weighs 100-120 g. It grows well in spring-summer and rainy season, and has a yield potential of 12-15 t/ha in crop duration of 120 days.
The cultivar developed at Indian Agricultural Research Institute New Delhi through selection is suitable for growing only in spring-summer season. Its fruits are glossy green, thick, and medium long in size. First picking starts in 55-60 days after sowing. Average fruit weight is about 120 g and yield is about 15 t/ha.
An early maturing hybrid (50-55 days) developed at Indian Agricultural Research Institute New Delhi is suitable for cultivation in spring-summer season. Fruits are attractive green, medium long (13.5 cm) and medium thick (5.0 cm). Average fruit weight is 100 g and yield is about 20 t/ha.
A cultivar tolerant to fruit fly and mosaic disease developed at Chander Sekhar Azad University of Technology Vegetable Research Farm, Kalyanpur, Kanpur can be grown in spring-summer season, but found more suitable for cultivation during Kharif season. Vine growth is vigorous. Fruits are thin, long (30-50 cm), light green in color, and tapering to end. Yield potential is about 20 t/ha in crop duration of about 120 days.
This cultivar developed at Chander Sekhar Azad University of Technology Vegetable Research Farm, Kalyanpur, Kanpur produces green fruits of medium size. Its average yield is 12-15 t/ha.
A variety evolved at Tamil Nadu Agricultural University, Coimbatore through selection from a local cultivar produces 20-25 cm long dark-green fruits with raised tubercles and a single fruit weight about 100-115 g.
It is an induced mutant evolved at Tamil Nadu Agricultural University, Agricultural College, Madurai. Its fruits are greenish white with raised tubercles, and fruit length varies from 30 to 40 cm. The yield potential of this variety is about 30-35 t/ha in crop duration of 120-130 days.
A local cultivar from Tamil Nadu Agricultural University, Coimbatore produces dark-green extra-long fruits up to 50 cm with a single fruit weight of 300-400 g and yield potential of 15-18 t/ha.
It is a local cultivar from Tamil Nadu Agricultural University, Coimbatore. The fruits are extra-long (60-65 cm) with white colour, and the yield potential is about 15 t/ha.
A variety developed at Kerala Agricultural University, Vellanikkara through a single plant selection bears long green fruits with white tinge at stylar end. Fruits are about 40 cm long and 3.5 cm wide. Average fruit weight is 235 g with a production of 20-30 t/ha in 90-115 days duration.
It is a local collection from Rajasthan, purified and developed at Indian Institute of Horticultural Research, Bangalore. Its green fruits are short, spindle-shaped with smooth regular ribs, and thin fleshed with moderate bitterness. The variety is suitable for growing in both, spring-summer and rainy season. It yields 10-12 t/ha in a crop duration of 120 days.
It is a selection from Kerala Agricultural University, Sugarcane Research Station, Thiruvalla. Fruits are uniform white, spindle-shaped, and medium long (25 cm) with smooth tubercles. Average fruit weight is about 300 g and yield is 28 t/ha. It starts bearing 55 days after sowing and total crop duration is 4-5 months.
A selection from Kerala Agricultural University, Vellanikkara bears 30 cm long white fruits. The fruit breadth is 7.6 cm with a single fruit weight of 310 g. Its average productivity is 15 t/ha in crop duration of 4-5 months.
It is developed at Madhya Pradesh Krishi Vishvavidyalya, Rahuri through a selection from local material. Fruits are dark green and 15-20 cm long with raised tubercles. Average yield is 14 t/ha in crop duration of 160 days.
A variety tolerant to downy mildew is evolved by Madhya Pradesh Krishi Vishvavidyalya, Rahuri through selection from a cross between Green Long and Delhi Local. Fruits are dark- green and 25-30 cm long with raised tubercles. Its average yield is 23 t/ha in crop duration of 150-180 days.
It is developed at Konkan Krishi Vidyapeeth, Dapoli. Fruits are green, medium long (15-16 cm) and spindle-shaped with raised tubercles. Its yield potential is 24 t/ha. Fruits have good keeping quality with a maximum shelf life of 7-8 days at ambient room temperature.