Introduction
Cucumber (Cucumis sativus) was domesticated about 3,000 years ago and is indigenous to India. It is cultivated for fresh consumption or as pickling cucumber for preservation, marinated with vinegar, salt, dill, or other spices. It is an important salad crop cultivated both in north and lower as well as higher hills in India. Fruits varying in shape, size, and color contain 0.4% protein, 2.5% carbohydrates, 1.5 mg iron, and 2 mg of vitamin C in 100 g of fresh weight. Fruits are good for people suffering from constipation, jaundice, and indigestion. As per FAO estimate, the total cultivated area under cucumber and gherkins in India is 26,500 ha with 168,000 tonnes production and 7.5 tonnes/ha productivity.
Table of Contents (toc)
Climate and Soil
Cucumber is essentially a warm-season crop grown in subtropical, tropical, and hot arid regions. The soil temperature for ideal germination is 27°C. While for better pollination, fertilization, and fruit set, the temperature should be between 18°C and 32°C. Environmental factors play a significant influence on the sex expression of cucumbers. High temperature and long days induced more staminate flowers, while short days and low temperatures promote pistillate flowering. Besides, increased plant populations and low moisture also increase pistillate flowers. The intensity of light and time of day greatly influence anthesis more than temperature but temperature alone has a greater influence on another dehiscence and pollen fertility. Similarly, its cultivation in riverbeds during winter in India is a kind of indigenous system of vegetable forcing practiced with minimum risk of growing in low temperatures.
Cucumber can be grown well on deep sandy loam soil high in organic matter and well-drained. In heavy soil, the plant grows slowly, and fruits are inferior in size and quality. Cucumbers are fairly tolerant to acid soil. For its successful cultivation, the pH of the soil should be from 6 to 7. The acid tolerance limit of soil for cucumber is 5 pH.
Varieties
The cucumber varieties on the basis of the market are classified into 2 types i.e. eaten fresh (fresh or slicing market types) and consumed as a processed product (processing or pickling types). The quality attributes may vary for pickling and slicing cucumber. Cucumber varieties grown in India vary from small pickling types to very large and thick ones grown in Rajasthan, Gujarat, and northeastern states. Many high-yielding varieties and hybrids have been evolved which are as follows.
Gujarat Cucumber 1: This variety has been developed from a local collection at GAU, Anand. Fruits are longer, tender, and attractive with light green strips, soft and non-hairy with a longer shelf-life. Recommended for cultivation in Gujarat. Yield 24-26 t/ha.
Himangi: This variety has been developed through pedigree selection at MPKV, Rahuri. First picking starts 45 days after sowing. Fruit skin smooth and creamy yellowish color. Yield 30-32 t/ha.
Japanese Long Green: This variety was maintained at IARI Regional Station, Katrain (Himachal Pradesh). It is a temperate variety suited to hills and lower hills, (first picking 45 days after sowing). Fruit is 30-40 cm long, dark green surface with white spines with crispy flesh. Staking is beneficial for obtaining straight fruits. Yield 15-27 t/ha.
Kalyanpur Green: This variety has been developed at CSAUA&T, Kanpur. It is spreading type and early in fruiting. Fruits are thick, green, brown at maturity. It is suitable for cultivation in the rainy season. Yield 10-13 t/ha.
Pant Khira 1: This variety has been developed at GBPUA&T, Pantnagar. Fruits long (~20 cm), cylindrical with light white stripes. First picking starts 50-60 days after sowing. It is suitable for planting in both plains (March-July) and hills (April-May). Yield 13-15 t/ha.
Pant Shankar Khira 1: This hybrid is developed by GBPUA&T, Pantnagar. Fruits about 20 cm long, cylindrical and green with light stripes. First picking starts 50 days after sowing. Yield 20t/ha. Suitable for planting in plains as well as hills.
PCUCH 3: This hybrid has been developed at GBPUA&T, Pantnagar. Fruits are cylindrical, green, and medium-long (about 20 cm) with white spots. It has a long fruiting period and the first fruit can be harvested 50 days after sowing. Yield 25-27 t/ha.
Poinsette: This variety is an American introduction made by Regional Station, Katrain. Fruit is dark green, 20-25 cm long, tolerant to downy mildew, powdery mildew, anthracnose, and angular leaf spot. Yield 20-25 tonnes/ha.
Phule Subhangi: This variety has been developed through pedigree selection at MPKV, Rahuri. Fruits are smooth and attractive green with white strips at the apical end. It is tolerant to pod borer, anthracnose, leaf spot, and leaf miner under field conditions. Yield 30-32 t/ha in 90 days of crop duration.
Poona Khira: Fruits small-sized and pale-green. It is popular in Maharashtra and the border districts of Karnataka and Andhra Pradesh.
Pusa Sanyog: This hybrid was released by IARI Regional Research Station, Katrain. It is a cross between the Japanese Gynoecious Line and Green Long Naples. Fruits 28 to 30 cm long, cylindrical and dark green with yellow stripes, and crisp flesh. First harvesting after 50 days of sowing.
Pusa Uday: This variety has been developed at IARI, New Delhi. Fruit attractive with light green color and better shelf-life. Yield 20-22 t/ha.
Sheetal: This is an early maturing variety developed by Konkan Krishi Vidyapeeth, Dapoli. The vine grows up to 2.7 m with multiple branches and bears on an average 24 fruits per plant. Fruits are green with medium-length (25 cm) and weigh 300-350 g. Yield 30-40 t/ha during the rainy season and 20-23 t/ha during summer. The crop duration is about 90 days.
Solan Green: This variety has been developed at YSPUH&F, Solan. Fruits are light green and 11-15 cm long, Yield 18-20 t/ha.
Straight-8: This variety was maintained at IARI Regional Station, Katrain (Himachal Pradesh). It is a medium maturity cultivar (first picking starts 50 days after sowing) suited for hills. Fruit is thick, 20-25 cm long, straight with a round end, medium green, fleshlight green, crisp and heavy yielder.
Swarna Ageti: This variety has been developed by HARP, Ranchi. Fruits very cylindrical long, medium size (200 g), green with no placental hollowness and it is tolerant to powdery mildew. First picking starts 45-50 days after sowing. Yield 30-32 t/ha in 100-120 days of crop duration.
Swarna Poorna: This variety has been developed by HARP, Ranchi. Fruits are very cylindrical, long, medium size (300 g), light green without placental hollowness, and tolerant to powdery mildew. First picking starts 55 60 days after sowing. Yield 30-35 t/ha in 100-120 days of crop duration.
Swarna Sheetal: This variety has been developed by HARP, Ranchi. Fruits cylindrical, long, medium size (250 g), whitish-green without placental hollowness. First picking starts 60-65 days after sowing; gives a yield of 25-50 t/ha in 100-120 days of crop duration.
Other hybrids are DCH 1 and DCH 2 released by IARI, New Delhi; Phule Prachi and Phlue Champa identified by MPKV Rahuri; AACUH 1 and AACUH 2 by Assam Agriculture University and Solan Hybrids by YSPUH&F, Solan.
Cultivation
Soil preparation should be started 3-4 weeks before sowing, and the soil should be prepared thoroughly since proper soil preparations significantly reduce the soil compactness and allow the roots to penetrate deeper into the soil.
Planting
In India, furrow, bed, and pit (deep and shallow and mounds) sowing methods are followed. In furrow sowing, furrows are made at 1-1.5 m apart. Usually, sowing is done on the top of the sides of furrows, and vines are allowed to trail on the ground especially in summer. This is very useful in summer for efficient and economic use of water. In the channel, the pits should be made at a distance of 0.5-0.75 m. In northern India, seeds can be sown in alkathene bags (15 cm x 10 cm) of 100-200 gauge and germinated under protected cover to avoid low-temperature injury. The seedling has a great future in cucumber, whose growing season is restricted in northern plains due to its thermosensitivity (sensitive to the low temperature of January and high temperature of May).
Cucumbers are grown both in the summer and rainy seasons. For summer, sowing is done during February March, and in the rainy season, sowing is done in June July in northern India. In Western India, cucumber sowing extends from September to February. Under protected conditions, crops can be raised throughout the year. In southern and central India, it is sown in October-November. In Maharashtra, it should be sown in January-February (summer crop) and June-July (rainy season crop). In hills, its sowing time is April May.
The seed rate of cucumber depends upon the sowing distance between hills and rows. The recommended seed rate is 1.5 to 2 kg/ha. Seed treatment is done with carbendazim @ 2.5 g/kg of seeds.
Training and pruning
Training and pruning at proper stage(s) are required for maintaining a balance between vegetative and reproductive growth and to support the plant. Pruning of all secondary shoots up to 5 nodes gives maximum yield in cucumber. The plant should be trained on a bower made of bamboos or cemented poles, and wire stretched across both sides which facilitate to reduce the plant spacing and increase quality and yield. Vines are generally not trained when cucumber is grown commercially. However, staking of plants particularly in the rainy season is helpful in checking the rotting of fruits.
Nutrition
Cucumber is quick growing crop and responds well to manuring and fertilization. Fertilizer requirements will vary depending upon the soil type, fertility, previous crops, system of cultivation, cultural practices, method of fertilizer application and duration of crops, climate, and yielding ability of varieties/ hybrids. The recommended nutrients for different. states in India vary from 50-100 g N, 34-50 g P, 50-75 Kg depending on the soil in different states. Liquid sprays of urea promote growth and improve fruit quality more than ammonium nitrate. A whole amount of phosphorus and potassium along with a half to a three-fourth dose of nitrogen should be applied at the time of sowing or seedling transplanting. The remaining dose of nitrogen should be top dressed in two splits i.e. 30 and 45-60 days after sowing or transplanting. The dose of nitrogen may be reduced or omitted (particularly by the second split) if growth is luxuriant.
Irrigation
Cucumbers require proper moisture during the growing period especially during the flowering and fruiting period. Water stress and excess can seriously reduce marketable and quality yields. Moisture requirements of cucumber crops range from 15 to 24 inches, depending on climate, soil type, and plant populations. On average, cucumbers need 2.5 cm of water each week, which may increase to 5 cm per week during summer and dry weather. The number of irrigation and quantity of water is based on the consumptive use of water by crop and the relationship between the available moisture of root zone and yield potential of the crop. In arid areas, furrow irrigation is preferred to reduce evaporation losses; while in humid regions, the overhead sprinkler is used. Light and frequent irrigations are preferable in comparison to heavy and delayed irrigations.
Aftercare
Thinning of extra seedlings is essential and finally one or a maximum of two plants per pit should be maintained. Depending upon the severity of weeds, a total of 2-3 weeding operations would be required at an early stage of growth. A single application of stomp as pre-emergence (pendimethalin) 30 EC i.e. 3.3 liters mixed in 800 litres of water can be used in one hectare which checks the weed emergence up to 30-35 days from sowing. At the time of weeding and earthing-up, top dressing of nitrogenous fertilizers should be done. When vine starts spreading, weeding between rows or ridges becomes unnecessary since vine growth can smother the weeds. At later stages, pull out big weeds manually without disturbing the vines, if plants are not trained.
Diseases and Pests
Diseases encountered in the crop are downy mildew, powdery mildew, and anthracnose. Cucumber green mottle mosaic is the major virus affecting cucumber.
Insect pests in cucumber are red pumpkin beetle, leaf miner, leaf-eating caterpillar or cucumber moth, Solenopsis mealybug (Phenacoccus Solenopsis) and red spider mite are important.
Harvesting and Post-Harvest Management
External fruit quality differs for various market types. In India, generally mottle green with green ting or white with green ting skin color are preferred for table purposes. Parthenocarpic English slicing cucumber is suitable for growing under glasshouse conditions. It has uniform green fruit with small-spine and length and diameter ratio is more than 4, while Asian greenhouse type is dark green tend to bear comparatively more warts. In contrast, medium green processing cucumber has a shorter length and diameter ratio and fruits are straight blocky in shape.
The requirements for internal fruit quality between fresh market and processing types are different. For fresh market keeping quality (i.e. no shrinkage) and internal taste (i.e. non-bitter) and color, characteristics are important. For processing, cucumber fruits having small seed cavity size, without placental hollowness and carpel separation are more important. The breeding for quality improvement should be concentrated on these parameters.
Fruits of cucumber attain edible maturity within a week from anthesis. The picking of fruits at the right edible stage depends upon individual varieties and marketing requirements. In salad or slicing cucumber, green skin color should not turn brownish-yellow. White spine color is also a useful indication for their edible maturity. Further, over-mature fruits show carpel separation in the transverse section of the fruits. If cucumber vines are trained vertically their fruits reach harvestable size a day or two days early. The cucumber should be picked at 2 days intervals. However, their seeds mature 25-30 days after pollination. For seed purposes, pale-yellow and golden-yellow (mature fruit color) cucumber should be harvested, in white and black spine varieties respectively. Its yield varies according to the system of cultivation, cultivar, season and other factors. Generally, cucumber yield is about 15-20 t/ha.
Cleaning
Any remaining soil in the ground spot area or other surface stains on fruit should be removed after harvesting. The fruit should be washed with clean and properly sanitized water to reduce the potential for the spread of disease. Sodium hypochlorite (household bleach) is commonly used since it is an inexpensive and readily available wash water sanitizing agent. It is effective against decay organisms when added to the wash water at a concentration of 150 ppm and the water is maintained at a pH of 6.5. As the wash water becomes contaminated with soil and organic matter, the sanitizing ability of hypochlorous acid is diminished. Therefore, the wash water tank should be changed when necessary and filled with clean water with 150 ppm hypochlorous acid. After cleaning, the fruit is generally placed on a soft mesh or wire table to dry before sorting and grading.
Grading
Table or slicing cucumber quality is primarily based on size, uniformity of shape, firmness, and skin color. Additional quality indices are the number of surface blemishes and peel injury and incidence of decay. High-quality cucumber fruit should be straight, uniformly green, and have an appropriate length-diameter ratio.
Waxing
Cucumber fruits are often treated with food-grade liquid wax after grading. The purpose is to replace some of the natural wax removed during washing and cleaning, to retard water loss, and to improve appearance. The wax is similar to mineral oil and may be applied by hand rubbing.
Packing
Cucumber fruits should be packed in strong, well-ventilated containers. Cucumbers for export should be packed in strong well-ventilated fiberboard cartons with a minimum test strength of 275 psi. Carton size varies depending on market destination, but typically contains 25 kg of fruit.
Cucumbers are mainly used as a salad crop; however, gherkins are preserved in vinegar, acetic acid, and brine solution and exported to other countries. Generally gherkin exports are in bulk form in 220 liters, packed in food grade HDPE drums (high-density polyethylene). This is later repacked by the importers into smaller, ready-to-eat consumer packs to suit their consumers’ requirements. The country has exported 2,18,749.79 MT of cucumbers and gherkins to the world worth 955.25 crores during the year 2013-14. The gherkins are mainly exported to the USA, France, Germany, Australia, Spain, South Korea, Canada, Japan, Belgium, Russia, China, Sri Lanka, and Israel. Russia also buys large quantities of bottled Indian Gherkins from India.
