Everything you need to know about cucumber cultivation, production and harvest. Learn about:- 1. Introduction to Cucumber 2. Origin and Distribution of Cucumber 3. Composition and Uses 4. Climate Required for Cultivation 5. Soil Required for Cultivation 6. Sowing Time 7. Manurial Requirement for Cultivation 8. Irrigation Requirement for Cultivation 9. Intercultural Operations 10. Harvesting and Yielding 11. Cultivated Varieties.
Contents:
- Introduction to Cucumber
- Origin and Distribution of Cucumber
- Composition and Uses of Cucumber
- Climate Required for Cultivating Cucumber
- Soil Required for Cultivating Cucumber
- Sowing Time of Cucumber Seeds
- Manurial Requirement for Cucumber Cultivation
- Irrigation Requirement for Cucumber Cultivation
- Intercultural Operations of Cucumber
- Harvesting and Yielding of Cucumber
- Cultivated Varieties of Cucumber
1. Introduction
to Cucumber:
Cucumis includes about 30 species of annuals and herbaceous perennials of the Old World tropics and warm temperate regions. Among them cucumber (Cucumis sativus L.) is one of the most important commercial crops grown extensively throughout India, however, China leads in average production followed by India, the USSR, the US and various European countries.
The fresh taste and aroma of the cucumber are determined by free organic acid and essential oils present in it. Takei and Ono (1939) attributed that flavor of cucumber is said to be derived mainly from the 2,6 nonadienal, with assistance from 2-hexenal, the more astringent taste being contributed by 2-noenal.
In cucumber, Kemp et al. (1974) identified some saturated straight chain aldehyde volatile compounds, i.e., inonanol-trans-2-nonen-1-01, cis-3-nonen-1-01, cis-6-nonen- 1-01, trans, cis-2-6-nonadien-1-01, cis-3, 6-nonadien-1-01, cis-6-nonenal and C10-C15, which were not reported earlier.
Cucurbitacins, which are responsible for bitterness in cucumber, are the free glycosides or in bound form pertaining tetracyclic triterpenes compounds, and are greatly found in fruits and roots with leaves being normally. The pollen also contains bitter principles, and hence, when bitter pollen fertilizes non-bitter ovules, the resulting fruit becomes bitter. This phenomenon is called metaxenia.
2. Origin and Distribution
of Cucumber:
The cucumber believed to have been indigenous to India, as mentioned “Urvaruka” in the “Rigveda” or “Ervaruka” in the “Charaka Samhita” and its cultivation dates back to 3000 years. Sir Flinders Petrie an Egyptologist found the remnants of cucumber in tombs of Egypt about 2300 B.C. and established the species as one of the most ancient cultivated species by man.
In the Caucasus region, there are names for the cucumber that predate Sanskrit. In due course of time from India, it spread to China, and even earlier and more rapidly to the West where it was much appreciated by the Greeks and the Romans. Later on it was introduced throughout the Europe by ‘Greek’ and ‘Roman’ empires.
Great settlers Columbus grew the crop in the year 1494 on the island of Haiti, and Spanish introduced cucumber in North America where now it is adopted as a popular commercial crop. India being the primary center of origin bestowed with a wide range of variability. The chief evidence offered for this viewpoint is the finding of Cucumis hardwickii Royle, found at the foot of the Himalayas, which is supposed to be progenitor of Cucumis sativus.
3. Composition and Uses of Cucumber:
Composition:
Nutritionally, cucumber is low in calories (113-148 kcal) and low in minerals and vitamins, however, its excellent flavour and texture make the cucumber one of the most prized vegetables. Cucumber in its fresh form possesses several easily digestible nutrients (Table 9.1).
It is a good source of iodine, and contains a total of 4-6% of dry substances, approximately 2% sugars, 1 % albuminous substances, 0.7% cellular tissue and 0.1% fat but there are some other species like Cucumis sativus var. xishungbanesis from China that have orange flesh and possess more β- carotene than other cucumbers. The nutritional composition of cucumber fruit is given below in Table 9.1.
Uses:
The fruits of cucumber are usually eaten fresh or in salads. Besides, fruits are cooked, pickled, or used to make preserves. Young leaves and stems are usually cooked in Southern Asia. Decorticated seeds and extracted oils are used by the confectioners in a variety of ways. The West Indian Gherkin (Cucumis angaria L.) and the African horned cucumber or Jelly melon (Cucumis metuliferus) are far more limited in their use.
Medicinal applications of cucumbers are too plentiful to enumerate. Its fresh consumption is very useful food for jaundice patients, known for its diuretic and antipyretic properties, sharply reduces gastric acidity, prevents constipation, and produces cooling effects during hot summer. It plays an important part in regulating the work of intestine by boosting its function.
The low calorie content of cucumbers makes them indispensable part of the diet of those suffering from obesity. It also allows for the supernumerary amount of cholesterol to be cleared from the body. Mashed cucumber (100 g on empty stomach) is recommended for those suffering from spastic colitis. The crystalline compound of the fruit serves sanitary purpose. The cucumber is used in folk remedies in the treatment of gout, tumors as well as lungs and kidney diseases.
A ferment of the approximate composition of insulin, which makes a dietary product of particular value, has been developed from the cucumber fruits. The juice of cucumbers is used as a cosmetic preparation like health and beauty products including perfumes, lotions, soaps, and shampoos. Indigenous practitioners create medical concoctions from the roots, leaves, stems, and seeds.
4. Climate Required for Cultivating Cucumber
:
Cucumber is a warm season crop that grows best at a daily mean temperature of 18-24°C, however, the most ideal growing temperature is 27.8°C. Optimum growth takes place at 15°C temperature and 80-90% relative humidity but temperature above 32.2°C and below 15.6°C causes slow growth. The seeds germinate well at 27°C. Environmental factors significantly influence the sex expression in cucumbers.
In general, increased plant population, high temperature, long days, low humidity, low moisture regime and high fertility especially nitrogen tend to increase staminate flowers, while decreased plant populations, low temperature, short days, high humidity, high moisture regime and low fertility especially nitrogen promote pistillate flowers.
In a critical study, Chaudhury and Pathak (1961) observed that light intensity and time of day greatly influence the anthesis more than the temperature but temperature alone has greater influence on anther dehiscence and pollen fertility.
Anthesis does not occur below I2°C. It is clear from the study that temperate gynoecious lines (SR 55/F and WI 2757) are unstable for gynoecy under high temperature and long photoperiodic conditions. Anther sacs (cells) opening start early in the morning between 2.30 and 3.45 a.m. and completed before 5.0 a.m. Optimum temperature (24- 25°C) and minimum temperature (22°C) is required for pollen germination. Nectar dispersion from stigma takes place at 16-17°C and continues up to 20.5-21.5°C. Stigma receptivity remains for 12-24 h.
5. Soil Required for Cultivating
Cucumber:
Cucumber can be grown on a wide range of soil types, provided they are well drained and fertile. Sandy-loam to loam soils rich in organic matter are most suitable for its cultivation, but early yield can be obtained from crop sown on light soils, while soils having moderate texture give ideal harvest.
In heavy soils, growth is adversely affected because of poor drainage. It is well known that cucumber is fairly tolerant to acid soils, but the best growth is obtained in soils having pH range from 6.0 to 7.0. The minimum acid tolerant limit of soil for cucumber cultivation is pH 5.0.
6. Sowing Time
of Cucumber Seeds:
Cucumber is grown twice in a year once as spring-summer crop and another as rainy season crop. For spring-summer crop, the sowing is done during February-March, and for rainy season crop, in June-July. In western India, cucumber sowing extends from September to February. In glass houses, the crop can be raised throughout the year. Heat unit system may also be used to space planting dates for successive harvests of cucumber.
By knowing the number of heat units required to reach first harvest for a crop type and maturity group (early, mid, and late season) a grower can schedule plantings based on heat summations so that one harvest would be finishing as another is about to begin.
One system uses a base temperature of 15.6°C and a ceiling temperature of 32.2°C, and another system determines heat unit by subtracting a base temperature of 12.8°C from the daily mean temperature. Cumulative difference in heat units required to reach maturity and some variation may be expected for both location and season.
Seed Rate, Spacing and Plant Population Density:
The recommended seed rate is 2.5 to 3.0 kg/ha. Cucumber seeds are sown at a spacing of 2.0- 2.5 m row to row and 80 cm plant to plant. Optimum plant density is essential to harvest high yield and quality fruits. Very high and very low plant densities are undesirable. A plant spacing of 2.5-3.0 m × 60 cm for Punjab and 1.5-2.0 m × 45-60 cm for Delhi area has been recommended by Seshadri (1986).
The pits are dug at a row-to-row and plant-to-plant spacing of 1.8-2.5 m in West Bengal, while a recommended spacing is 1.2-1.5 m × 60-90 cm. Staub et cd. (1992) evaluated the effects of three sowing rates 109000, 242000 and 272000 plants/ha and concluded that the number and yield of fruits per hectare increased with increasing plant density, however, fruit yield per plant decreased. Maintaining three lateral shoots per plant Young et al. (1995) obtained highest yield (380 t/ha) from cucumber cv. Japanese White at a population density of 45,000 plants/ha.
i. Shallow Pit or Flat Bed Method:
In this method, shallow pits of size 60 × 60 × 45 cm are dug keeping a distance of 120-150 cm and left open for a week for partial solarization. Thereafter, each pit is filled with a mixture of sufficient soil and 4-5 kg well-decomposed farmyard manure and a part of fertilizers like urea (50-60 g), single super phosphate (100-120 g), muriate of potash (80 g) and Furadon (1.0-1.5 g). The manure and fertilizers should thoroughly be mixed before filling the pits, and circular basins are made after filling the pits. Per hill, about 3-4 seeds are sown at a depth of 2-3 cm.
Deep pit method is commonly practiced for growing cucumber in riverbeds. In this method, the circular pits of 60-75 cm diameter and 1.0-1.5 m depth are dug at a distance of 1.2-1.5 m. The pits are filled with a mixture of well-decomposed farmyard manure (10-12 kg), urea (80 g), single super phosphate (100 g) and muriate of potash (70-80 g). Sowing is done as in shallow pit method.
In this method, channels of 40-50 cm width and 15-20 cm depth are opened manually or mechanically at a distance of 2.0-2.5 m. The above-specified mixture of well-decomposed farmyard manure, fertilizers, and Furadon is thoroughly mixed into the soil where seeds are to be sown. Per hill, two seeds are sown on both side edges of raised beds keeping 30-40 cm distance between plants.
In this method, 15-20 cm raised mounds are generally prepared. After thorough incorporation of specified mixture of well-decomposed farmyard manure, fertilizers and Carbofuron, 4-6 seeds in each mound are sown at a depth of 2-3 cm. In this method, the most important point, which is to be kept under consideration, is to maintain adequate moisture up till seedling emergence.
Protected Nursery Production and Transplanting:
Sometimes, it is not possible to sow seeds timely in outdoor fields due to natural calamities like excessive or unwanted rains, hailstorm, low temperature, or accommodation of previous crops. Under such circumstances, nursery may be raised in limited area under strict supervision adopting poly house or low tunnel technology.
Adopting this technique, the cucumber can be grown as an extra early spring crop in north plains, and as such, the crop can be advanced 30 to 45 days than normal sown crop in field. In winter months (December-January), the seedlings are raised in 100- gauge thickness polyethylene bags of 15 × 10 cm size, which are filled with a mixture of soil, sand and well-decomposed farmyard manure, or compost in equal proportion.
The bags before filling are provided with 4-5 holes on upper sides for proper aeration and 2-3 holes in the bottom to drain out excess water, essentially needed for normal root growth. Composted saw dust can also be used for raising cucumber seedlings.
The seeds prior sowing should be treated by soaking in 0.2% Captan solution for about 2-4 h. Per bag, at least two seeds are sown at a depth of 2.5 cm. After sowing seeds, a light irrigation is applied using rose can, and the bags are placed in poly or greenhouse. Seedlings of 30 days are usually transplanted.
Vegetable production in greenhouse through grafting was first initiated in Japan and Korea in the late 1920 and in 1990, respectively, and the area under grafted cucumber accounted for 59% of the total production in Japan. Grafting is very effective tool for controlling soil borne diseases and nematodes but it is laborious and time consuming.
Canizares and Goto (1998) found that grafted plants showed better and faster growth and development and higher fruit yield with better quality than un-grafted plants. Total fruit number and the number of commercially acceptable fruits were very high. Early yield was better from grafted plants than non-grafted plants. Under Indian conditions, grafting technique may be quite useful against several prevailing races of disease causing pathogens and insect-pests.
7. Manurial Requirement
for Cucumber Cultivation:
Cucumber being quick growing succulent crop responds well to the application of manure and fertilizers. About 20-25 t/ha well decomposed farmyard manure or compost should be added in the soil 20-25 days before sowing and mixed properly through cultivators during field preparation. The fertilizers requirements vary depending upon the growing season, soil type, fertility, previous crop grown, system of cultivation, cultural practices adopted, method of fertilizers application, duration of crop, and yielding potential of variety/hybrid.
Cucumber cv. Long Green produced maximum and minimum number of male and female flowers, respectively when nitrogen was applied at 80 kg/ha, but higher nitrogen rates (120 kg/ha) delayed the appearance of first female flower. Significant yield increase in plots receiving nitrogen at 120 kg/ha, however, further increase in nitrogen rates from 120 to 200 kg/ha produced no significant effect.
Urea as a source of nitrogen can be used in small quantity to root zone during earthing up or drip watering. Application of liquid urea promotes growth and improves fruit quality than ammonium nitrate. Number and length of nodes, weight of fruit and total yield increased when solution culture of ammonium sulfate or calcium nitrate applied at 300 ppm.
On the contrary, when urea or NH4+ represented more than 50% of N source, the plant growth and fruit yield reduced drastically. Earliness, higher yield, and improved fruit quality can be achieved if slow releasing fertilizers like KNO3 + NH4NO3 or NH4NO3 + K2SO4 + MgSO4 are applied in the form of perforated plastic tubes. Increase in yield can also be obtained by spraying 3% urea thrice at weekly interval starting after first picking.
Cucumber plants gown in cooler greenhouse (14-29°C) and receiving N at 2 and 4 g per plant produced a yield of 120- 250 q per 100 m2 compared with 70-106 q per 100 m2 in warmer (19.5-40°C) greenhouse. The quality (freshness) of canned cucumber before processing was found better under application of N at 80-120 kg/ha.
Phosphorus is the nutrient, actions of which become visible within 20-30 days of germination. In cucumber field, deficiency of phosphorus may be noticed as stunted growth, reduced leaf size, stiff dark gray-green coloration, scorching of leaves, drying of tissues, and interveinal and marginal chlorosis, and brown colour of roots may be observed while plants are uprooted.
Application of super phosphate in bands 7.5 cm to the side and 5.0 cm below the seed level increased the yield of cucumber. Increasing trend of yield was observed by increasing phosphorus rates from zero to 170 kg/ha but beyond this level the yield reduced by 38%.
Potassium deficiency symptoms in cucumber lead to chlorosis, bronzing, scorching, little leaf, and tip burning. Calcium deficiency is developed as pale green coloration of leaves with upward and inward curling, downward cupping, marginal chlorosis and less root and top growth.
The most important micronutrients that are quite helpful for growth and development of cucumber arc magnesium, sulfur, zinc, and manganese, however, sometimes, boron, copper, iron, molybdenum, silicon, and lithium deficiency may be observed most likely in alkaline soils and under high phosphorus fertility.
Soaking of seeds in solution of CuSO4 at 0.005%, MnSO4 at 0.1% or Al2 (SO4) at 0.1% or in a mixture of all three nutrients for 12 hours increased the germinability, promoted growth and development of young plants, stimulated P uptake, and increased the yield.
Pre-sowing seed treatment with 0.05% solution of boron, zinc, manganese, or molybdenum salts promoted hypocotyl growth. Spraying cucumber plants with borax, zinc sulfate, or manganese sulfate at 0.01% stimulated growth, advanced flowering, enhanced production of male and female flowers and improved seed yield and quality.
Method and time of application can be concluded as organic manure is mixed in soil at the time of filling soil mixture in pits. When cucumber is sown in flat beds, well-decomposed organic manure is applied through broadcasting during field preparation. Whole amount of phosphorus and potassium along with ½ to ¾ 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 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. In general, band placement of fertilizer application was found most effective with low fertilizer rates.
Where drainage facility and quality of irrigation water are poor, and field is having high soluble salt concentration, a combination of band and broadcast placement can be adopted to provide adequate nutrients to the plants and to lower the salinity injury. Application of fertilizer like urea should be used only in good light and temperature condition for better uptake.
8. Irrigation Requirement
for Cucumber Cultivation:
Cucumber requires a continuous supply of moisture during the growing period, especially during blossoming and fruiting. Water stress (deficit or excess) reduces the marketable yield seriously. The water requirement of cucumber crop ranges from 37.5 to 60 cm, depending on climatic conditions, soil types, plant populations, and cultivars. On an average, cucumber weekly needs 2.5 cm of water, which may increase to 5.0 cm per week during hot and dry weather, or when the plants are in fruiting phase.
Number of irrigation and quantity of water required by the crop are based on the consumptive use of water and relationship between the available moisture in root zone and yield potential of the crop. Sufficient moisture should be made available in root zone to facilitate efficient absorption of nutrients, which are indispensable for getting higher yield from any crop, however, the crop grown in riverbeds generally does not require irrigation probably due to high water table and use of heavy amount of farmyard manure or compost, which possesses fairly good water retentive properties.
In arid regions, furrow irrigation method is preferred to reduce water loss through evaporation, while in humid regions, overhead sprinkler or gun type system is preferred more. Drip irrigation not only saves water but also favors better fruit set and reduces disease attack in cucumber. During flowering, irrigation should be so scheduled that it may not interfere with bee-pollination in morning hours.
Light and frequent irrigations are preferable in comparison to heavy and delayed irrigations. In studies with cucumber cv. Monastyrski in Poland, the cavities found even in very young fruits were subjected to the conditions of low soil moisture and high N-nutrients. Water stress condition has also been reported to cause seed yield reduction in cucumber.
9. Intercultural Operations
of Cucumber:
Intercultural operations that include thinning of seedlings, protection of young seedlings and vines from frost, chilling winds and high temperature, weeding, earthing, and training of vines are essential to harvest a good yield from cucumber crop. Practicing thinning operation one to two seedlings are maintained per hill. Weeds in field have been observed to reduce yield by 15 to 60%, depending upon their intensity. In general, 2 to 3 weeding may be sufficient to keep the field weed free.
Pre-emergence application of weedicides like pendimethalin (Stomp 30 EC) 3.3 litre in 800 litre of water per hectare can be used to check the weed emergence up to 35-40 days after sowing. One hand weeding at about 35-40 days after sowing is effective to control the weeds. Application of treflan 0.8 kg/ha 18 days before sowing controlled the weeds effectively and increased the yield of cucumber.
One hoeing of furrow or basin following earthing up near base of stem improves plant growth and development. Proper training of plants is very essential for growth, flowering and fruiting, and improves yield and quality of cucumber. Training of plant on bower or stakes using coconut, jute, or plastic rope should be started when the plants attain a height of 30-40 cm.
Staking trial on cucumber cv. Bhaktapur Local for off-season production in Nepal reveal that on an average staking with Jute string gave 5-6 and 29% more marketable fruits than the farmers practice of staking (bamboo sticks or tree branches) and no staking, respectively. Pruning of all secondary shoots up to 5th node gave significantly high graded fruit yield compared to un-pruned plants.
In cucumber, mulching has been found beneficial in increasing fresh fruit yield. During winter and spring-summer, mulching has become an essential part of cucumber cultivation. In riverbeds, the cultivation of cucumber without mulching is quite difficult since mulching in winters helps in raising soil temperature, and thereby, protects the crop from frost.
Covering of soil between double rows of cucumber plants with bands (strips) of transparent and blue plastic sheet decreased the incidence of vims 70 and 97%, on the contrary, covering with black plastic film was found ineffective in preventing virus incidence.
Use of plastic film as mulch increases the absorption of N and K and the accumulation of dry matters during the early stage of fruit formation and also increases P absorption at full fruit set. From economic point of view, the use of black plastic or straw mulch gives higher cucumber yield, and covers all additional costs.
Covering with clear polyethylene increases soil temperature more than with black polyethylene, however, covering with black mulch increases air temperature more than clear mulch. Early cucumber yield is increased 2 to 6 fold by the use of covers. Mulching with both black and clear plastic results in higher cucumber yield, not only this, mulching also helps in accumulation of more dry matter, early flowering and increases nutrient uptake.
Moreover, mulching with black plastic film increases the net N mineralization in soil, which might be attributed to reduced metabolic quotient, i.e., the increased efficiency of energetic soil microbial population.
In addition, the population of ammonifying microorganisms is increased, and contrarily, the population of nitrifying microorganisms is decreased. The best cucumber yield of 60.27 t/ha was obtained with red plastic film mulch, whereas, the yield with black plastic film mulch was 47.03 t/ha and with no mulch 42.33 t/ha.
Use of Plant Growth Regulators:
Cucumber responds well to various plant growth substances in respect to seed germination, vegetative growth, sex modification, and fruit development. Pre-sowing seed treatment with plant growth substances, like Fuccicoccin 6-8 ppm, Gibberellic acid 25 ppm + Ethephon 50-100 ppm and KH2PO4 (3%) enhances seed emergence in cucumber. Maleic hydrazide (50-100 ppm) and Ethrel (100-120 ppm) were noticed to induce more number of female flowers and fruit set in monoecious varieties.
Foliar spray of NAA 100 ppm was most effective for induction of pistillate flowers, however, Singh and Singh (1984) reported that this chemical at 25- 100 ppm is quite responsive to promote female to male ratio and yield in cucumber. Sharma et al. (1982) recommended application of caffeic acid 50 ppm for better fruit set.
Ethephon application in cucumber has been most effective at lower concentration 50-100 ppm for sex modification or 150-250 ppm. Foliar sprays with TIBA at 50 ppm, GA3 at 40 ppm, MH at 100 ppm or Ethephon at 150-500 ppm has been reported to give best fruit yield.
Complete parthenocarpy has also been reported with pre-anthesis sprays of GA at 100 ppm in cucumber. The gynoecious lines of cucumber are maintained for hybrid seed production by spraying GA3 at 1500-2000 ppm, which induces staminate flowers. Silver nitrate at 500 ppm has been reported to be as effective as GA3. Application of CCC 25-50 ppm is also recommended for above said purpose.
10. Harvesting
and Yielding of Cucumber:
Picking of fruits at right edible maturity stage is usually dependent on an individual cultivar, being used for cultivation. In salad or slicing cucumber, dark green skin colour should not turn to brownish yellow, and white spine colour that turns to brownish black on maturity is also a very useful indication for judging the right stage of edible maturity since over mature fruit would show carpel separation in transverse section of fruit.
Depending upon the cultivars, the optimum length of fruit may be around 20-25 cm at edible maturity stage. In small-fruited types, which have pale green skin colour, the desirable fruit length is around 8-12 cm. In western countries, there are definite standards of size for picking cucumbers.
However, in India, fruits are usually harvested when they have reached the desired marketable size, which takes about 40-50 days after sowing, and about 7-10 days after setting fruits. In salad or slicing cucumbers, dark green colour fruits are picked after attaining 15-25 cm length, while for pickling they are harvested just after attaining a length of 5-10 cm since they are pickled as whole fruit in brine.
Mechanical harvesting is not at all possible in cucumber due to serious damage caused to the vines, thus, the fruits are picked manually by hand to avoid injury to the vines, but most of the pickling cultivars are adapted to machine or once-over harvest. The fruits are harvested along with the stems attached to.
Careless or delayed picking reduces the yield since maturing cucumber exhausts the vine more than many young ones, thus, the picking should be done at 2 days interval to avoid the fruit to be over mature since over mature fruits turn brownish-yellow and show separation of carpel in transverse section.
The vines should be handled carefully and gently while harvesting the fruits and it is advisable to cut or clip away the fruits rather than twisting them off. Slicing cucumbers fetch better price in the market when they are sufficiently long, moderately slender and dark green in colour, however, reverse is true with the pickling cucumber.
Post-harvest handling of cucumber is a necessary measure in order to supply consumers, caterers, and processors with fresh produce independent of distance in space and time between producer and consumer. Prior to harvesting, the produce quality is built up during growth and development, whereas, handling and storage inevitably lead to quality loss.
Cultivars, agronomical conditions, and harvesting and handling practices are critically associated with other factors, which decide the shelf life of fresh produce in storage, however, quality loss is inevitable because harvesting and handling impose stress, and post-harvest conditions are vital for the maintenance of good end-product quality. Fleshiness and succulence due to high water content make the fresh fruits and vegetables perishable with a limited shelf life.
Cucumbers for fetching better price in the market should be firm, straight, uniformly smooth and dark green so prior to marketing the fruits are subjected to sorting and grading, which are done in field or in packing house station.
Slicing and pickling both the cucumbers are generally graded on the basis of fruit shape, size and general appearance, however, slicing cucumbers graded by fruit length, diameter, shape, and colour should have preferably a length of 15-20 cm and diameter of 4-5.5 cm, and pickling cucumbers are graded by fruit diameter into No. 1 (up to 2.5 cm), No. 2 (2.5-3.75 cm), and No. 3 (3.75-5.0 cm). The fruits having a diameter greater than 5 cm are considered oversized. Field grown cucumbers are usually separated into two grades, i.e., grade A and grade B.
Cucumbers soon after harvest are hydro cooled to remove field heat. Immature fruits can normally be stored for short period. However, the mature fruits depending upon variety can be stored for several weeks to many months provided they are stored under most appropriate conditions. Fruits mature rapidly at temperature above 10°C, resulting in colour change from green to yellow. They can safely be held 10-14 days at 10-13°C temperatures and 95% relative humidity.
Fruits being tropical are subjected to chilling injury if they are held longer than 2 days at temperature below 10°C. Yellowing is accelerated if cucumbers are stored at a temperature above 16°C or with other crops giving off ethylene. Slicing cucumbers prior to marketing may be waxed and packed in waterproof cardboard cartons to reduce moisture loss.
The optimum temperature to retard softening is about 13°C at a relative humidity of 95% with a maximum storage period of approximately 14 days. Working with cucumbers Kooten et al. (1997) emphasized that during transport and storage, the colour should be protected for better acceptance in the market. Similarly, Schouten and Kooten (1998) reported very less changes in colour of cucumber when the fruits are picked in a very early stage of maturity.
Yield is a variable factor that depends upon the variety (open pollinated or hybrid) used, season of planting, even time of planting in growing season, fertility status of soil, and agro-techniques followed during crop cultivation. On an average, yield varies from 20 to 30 t/ha in crop duration of 100-110 days.
11. Cultivated Varieties of Cucumber
:
Cucumber cultivars according to their intended use are usually classified as fresh market slicing, pickling, or green house cucumbers. This classification includes several fruit characteristics such as shape, colour, spine type (coarse or fine), spine colour (white or black), fruit length/diameter ratio, skin thickness, and surface.
For fresh market, the slicing types that are long, smooth, straight, and thick-skinned with a uniform medium dark green colour are preferred, and the fruits for pickling are lighter green in colour, shorter, thinner-skinned and characterized by a warty surface.
The slicing cultivars have fewer spines than picking types. Each type should be cylindrical with blocky ends although round ended are also acceptable for slicing purposes. Green house cultivars should have relatively long narrow fruits with round ends.
i. Straight-8:
This high yielding early cultivar (50-55 days) developed at Indian Agricultural Research Institute, Regional Vegetable Research Station, Katrain, Kullu Valley (H.P.) is suitable for cultivation on hills. Leaves are dark green, fruit thick, 20-25 cm long, straight with round end, medium green, and flesh light green and crisp.
A high yielding temperate and extra early variety with 45 days maturity developed at Indian Agricultural Research Institute, Regional Research Station, Katrain, Kullu Valley (H.P.) is suitable for cultivation on lower hills, thus, popular among the farmers of J&K, H.P. and U.P Plants essentially require staking for obtaining straight fruits. Its dark green surfaced fruits with white spines are 30-40 cm long and flesh light green and crispy. It gives a yield of 20-25 t/ha.
This is an early maturing variety developed at Konkan Krishi Vidyapeeth, Dapoli (MS). The vine grows up to 2.7 m with 10 branches on each vine and bears 24 fruits per plant. Fruits are green with medium length (25 cm) and each fruit weighing 300-350 g. It gives yield of 30-40 t/ha during rainy season and 20-23 t/ha during summer season in crop duration of about 90 days.
A variety resistant to downy mildew, powdery mildew, anthracnose and angular leaf spot was originally developed at Charleston (South Carolina) USA, and in India, it is an American introduction made by Indian Agricultural Research Institute, Regional Research Station, Katrain (H.P.) and being multiplied by National Seed Corporation. Its dark green fruits are 20-25 cm long. It gives a yield of 20-25 t/ha. This is popular among the farmers of J&K, H.P., Uttaranchal, Chhattisgarh, Odisha, and A.P.
This variety has been developed by HARP, Ranchi. Fruits are very cylindrical long, medium sized (250 g), and whitish green without placental hollowness. First picking starts 60-65 days after sowing. It gives a yield of 25-50 t/ha in crop duration of 100-120 days. This is popular among the farmers of Punjab, Uttar Pradesh, Bihar, and Jharkhand.
A variety tolerant to powdery mildew has also been developed by HARP, Ranchi. Fruits are very cylindrical, long, medium sized (300 g) and light green without placental hollowness. First picking starts 55-60 days after sowing. It gives a yield of 30-35 t/ha in crop duration of 100-120 days. This is also popular among the farmers of Punjab, Uttar Pradesh, Bihar, and Jharkhand.
A variety tolerant to powdery mildew has also been developed by HARP, Ranchi through mutation breeding. Its medium sized (200 g) fruits are very cylindrical long and green with no placental hollowness. First picking starts 45-50 days after sowing. It gives yield of 30-32 t/ha in crop of duration of 100-120 days. This is also popular among the farmers of Punjab, Uttar Pradesh, Bihar and Jharkhand.
A selection from inbred of indigenous germplasm was evaluated as PCUC-28 under All India Coordinated Trials and identified for release in 2002. The fruits are 20 cm long and cylindrical with light white stripes. First picking can be done within 55-60 days after seeding. The yield potential is 150 q/ha. It is suitable for hill cultivation.
i. Pusa Sanyog:
An early and high yielding hybrid was developed at Indian Agricultural Research Institute, Regional Research Station, Katrain, Kullu Valley through a cross between ‘Japanese gynoecious line’ and ‘Green Long Naples’. Fruits are 28 to 30 cm long, cylindrical, and dark green with yellow stripes and crispy flesh. First harvesting can be done after 50 days of sowing.
A hybrid developed at G.B. Pant University of Agriculture and Technology, Pantnagar (Uttaranchal) is suitable for planting in plains as well as on hills. Vines are about 120 cm long and fruits about 20 cm long, cylindrical and green with light stripes. First picking starts at about 50 days after sowing. Its average yield is 20 t/ha. This is popular in Uttaranchal and U.P. The seeds of this hybrid and its parental lines could be obtained from the Division of Vegetable Crops G.B. Pant University of Agriculture and Technology, Pantnagar.
A commercially available slicing type cucumber hybrid is developed by the Indo-American Hybrid Seeds Co. in India. The fruit is about 25 cm long, dark green, and free from bitterness. It is tolerant to mildew, mosaic, anthracnose and scab diseases.