Everything you need to know about garden pea cultivation, production and growth. Learn about:- 1. Introduction to Garden Pea 2. Origin and Distribution of Garden Pea 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 and Few Others.
- Introduction to Garden Pea
- Origin and Distribution of Garden Pea
- Composition and Uses of Garden Pea
- Climatic Required for Cultivating Garden Pea
- Soil Required for Cultivating Garden Pea
- Sowing Time of Garden Pea Seeds
- Manurial Requirement for Garden Pea Cultivation
- Irrigation Requirement for Garden Peas Cultivation
- Intercultural Operations of Garden Peas
- Harvesting and Yielding of Garden Peas
- Cultivated Varieties of Garden Peas
- Controlling Diseases of Garden Peas
1. Introduction to Garden Pea:
The garden pea (Pisum sativum var. sativum), commonly known as English pea or green pea, is one of the oldest vegetables cultivated in the world. Currently, it ranks among top ten vegetable crops. Pea, an important legume vegetable, is being widely cultivated throughout the world as a cool season crop. It is most extensively grown in the temperate zone but best suited to cooler altitudes in the tropics and in winter season in the sub-tropics.
In India, it is mainly grown as winter crop for its green pods and for mature dry seed in the plains of northern India and as a summer crop in hilly regions. Pea crop also helps in improving soil fertility by fixing atmospheric nitrogen into the soil through nitrogen fixing bacteria present in its root nodules.
According to the current nomenclature, P. sativum is used for all edible forms of pea. The edible-podded, garden/sweet, and field peas are treated as subspecies within P. sativum. The garden pea is recognized as cultivar of P. sativum ssp. hortense, edible-podded pea as cultivar of Pisum sativum ssp. macrocarpon L. and field pea as cultivar of P. sativum ssp. arvense. The edible-podded peas are commonly known as sugar, snow, or China pea and have been assigned a botanical variety status as P. sativum var. saccharatum, but another edible pod type designated as Pisum sativum var. macrocarpon is known as sugar snap pea.
Edible-podded pea is a special type grown for its long pods rather its seeds and pods of each type tend to remain relatively succulent because parchment layer or the interior carpel wall does not form. English peas are types that are originated in England and called English peas to distinguish them from southern peas, which are really beans, not the peas. English peas (garden/sweet peas) are grown for seed.
2. Origin and Distribution of Garden Pea:
The garden pea is of antediluvian origin, however, its wild prototype is not found. Moreover, the attempts made to discover its history have been intricate due to the lack of its ancient name. In early time, the ancients could not differentiate prudently between peas and beans, thus, it is hard to ascertain its origin from ancient literature. Number of peas was known to the ancient Greeks and Romans.
The burnt pieces of pea were found in vestiges of lagoon dwellings in Switzerland and in ancient city of Troy, which was constructed during the Stone Age. Likewise, archaeological findings of carbonized pea seeds in western Asia and Europe have been dated to 7000 BC. According to Ensminger et al. (1994), peas were used by the Chinese in 2000 BC.
It is mentioned in the literature that the Chinese were the first who used the green pods and seeds of pea as food. In the eleventh century, the pods of wild pea were first sold in England. However, the green peas did not appear in the European markets until the 16th century.
Christopher Columbus apparently brought the peas to the West Indies and planted on Isabella Island in 1493, and by 1597, the famous herbalist Gerard listed four varieties grown in British gardens. By 1614, the peas were being cultivated at Jamestown, Virginia. Captain Bartholomew Gosnold planted New England’s first peas on the Island of Cuttyhunk in 1602. In 1787, Thomas Andrew Knight developed many of the modem American varieties in England by crossing different pea strains.
It is certain from the available evidences that pea is probably the indigenous to southeastern Europe and western Asia, and according to Vavilov (1949), Ethiopia, the Mediterranean, and Central Asia with a secondary center in the west are the centers of pea origin, however, the exact primary center is still not known. Later, the crop spread westward and northward throughout Europe, southward into Africa, and-eastward to India and China through the centuries.
Early times pea was small and belonged to the variety now called field pea (P. sativum ssp. arvense), which is believed to have originated from gray pea, still being grown wild in Greece and the Levant. Garden pea (P. sativum spp. hortense) is larger and sweeter than field pea and is of origin that is more recent (< 1000 years). Garden pea seems to have been derived from field pea by centuries of cultivation and selection for desired characters.
The wild cultivars of garden pea were never found, while the field pea is still found growing wild in the Georgian Republic of the old Soviet Union. Pea seems to be the first crop bred to produce new varieties with more desirable characteristics. By the end of the 19th century, many crossbreeding trials had been conducted but the most notable was conducted by the Austrian monk Gregor Mendel at Brunn, who provided the base to the science of genetics.
The quality of pea is associated with tenderness and high sugar content. At maturity the sugar content decreases and starch content increases rapidly due to conversion of sugar into starch. Being legume crop it is an excellent source of digestible protein for vegetarians. It provides carbohydrates, protein, amino acids, sugars, calcium, phosphorus, iron, vitamin A, B and C. The mealy texture of smooth pea seed is due to the high starch content. The nutritional composition of edible podded, green, and dry pea is given in Table 1.1.
Green peas are all time favorite vegetable as these befriend amicably with other vegetables such as potato, cabbage, cauliflower, beet leaf, pulao, cheese etc. The delicious perky pea soup, macro mat marvel, special peep pea and other preparations are very well known and consumed by large number of families throughout India and elsewhere in the world. Besides used as fresh vegetable, a large portion of total production of pea is canned, frozen, and dehydrated for consumption in off-season; for this purpose mainly wrinkle seeded varieties are preferred.
Some of the common terms worldwide used to describe the green pea are as follows:
1. Baby Garden Pea (Pisum Sativum Var. Humile):
It is an early maturing dwarf type pea.
2. Garden or English Pea (Pisum Sativum Var. Sativum L.):
It is a common garden pea with numerous cultivated varieties, and is referred to as shelling pea, green pea, or Austrian winter pea in honour of the Austrian monk, Gregor Mendel, who carried out and established the principles of genetic heredity based on his work with garden pea cultivars.
Garden peas are always shelled before use in the green or dry state since their pods are fibrous and have the parchment layer. They are freshly picked, eaten as young and small as possible, and are the most popular winter vegetable. Shelled peas are savored as a steamed vegetable and also enjoyed in soups, casseroles, stews, and salads.
3. Snow or Edible-Podded Pea (P. Sativum Var. Macrocarpon):
This pea is also universally known as sugar pea, sugar snap pea, snow pea, Oriental or Chinese pea, French pea, and Turkey pea. These peas are quite popular in Oriental stir-fry recipes. Sugar snap peas blend the best of both worlds. Snow peas or the edible-podded peas are savored for their crisp and succulent pods, not for their peas.
Similar to a snap bean, the snap pea has a cylindrical pod that is thick fleshy and breaks easily when bent. Snap peas are usually picked and consumed when the seeds in the pod developed to nearly their full size. In fact, if peas are allowed to develop full in the pods, the edible quality of the pods declines.
Snow pea pods lack the parchment like lining present in the pods of shelling peas, thus, pods are consumed as food directly without shelling and harvested just as the seeds begin to form. They are relished for both their juicy pods and their sweet tasting pease. Here, the pods and pease are allowed to mature fully for the finest flavor and texture. Although sugar snaps can be lightly steamed and stir-fried, they are in their glory when popped fresh from vine to mouth.
4. Field Pea (Pisum Sativum Var. Arvense L.):
Sometimes ago in developed countries, it was chiefly used as a fodder for cattle but now its mature ripe seeds are frequently used as a pulse in human nutrition, and the young immature green seeds are also used as a cooked vegetable. The seeds of field pea are relatively smaller and starchier than P. sativum var. sativum.
5. Austrian Winter Peas:
These peas sometimes referred to as Pisum arvense or Pisum sativum spp. arvense have pigmented stem, flowers, and seeds, and they are habitually cultivated as an autumn- winter crop in relatively cold provinces.
Having winter hardiness comparable to winter wheat these peas survive most winters. The crop harvested as dry seed is often used as feed for domestic animals. The Austrian winter pea is sometimes decorticated and split to produce yellow split peas when smooth yellow peas are short.
6. Dry Pea:
Dry pea is characterized by an indeterminate growth habit and smooth and starchy seeds. Its seeds may be green or yellow in color. The pods are picked when the seeds are completely mature and ripened and have moisture content of 12% or less. Dried peas are available round the year and used either as whole green or yellow peas or they are decorticated and split. Split peas are primarily used in making soups and purees.
7. Green Pea:
Its pods are harvested before the seeds commence to mature as contrasted with the dry pea, which is harvested after complete maturity of seeds. Green peas are also grown commercially for canning, deep freezing, and dehydration purposes.
8. Marrowfat Pea:
These peas most likely originated in England and most extensively use in Southeast. Asian countries have large compressed and fairly dimpled green peas, which are completely different from other dry peas in their seed types and quality characteristics. They have the typically dwarf plants with large size leaves and heavy vines that are normally short and well branched. They are generally late in flowering and as a result are late maturing when compared to Alaska types.
The seeds are about twice the size of a typical Alaska pea. Size and color of seed are considered the important quality characteristics, thus, large seeded with good dark green color marrowfat peas are said to be of good quality.
9. Petits Pois Pea:
It is the French equivalent for pea and is also used to describe a variety of pea known as the French Canner pea or the Turkey pea.
10. Freezer Type Peas:
In case of freezer type peas, the most important character is skin color of seed. These peas usually have a dark green seed skin that imparts characteristic dark green color to frozen peas. Similar to peas used for canning purposes, they are picked when tenderometer readings lie between 95 and 105.
The tenderometer readings above 105 indicate progressive decrease in sugar content due to its conversion into starch with a corresponding reduction in edible quality of pease. The freezing type peas at immature stage are sugary and appropriate for processing but become wrinkled and unfit upon dry seed maturity.
11. Canner Type Peas:
In processing stage, the canning type pea cultivars have typically light green color testa, which imparts the lighter color of canned peas, while the freezer-type pea cultivars have a dark green appearance at the same stage of maturity. The darker color freezer peas are usually unacceptable for canning purposes, as they tend to turn brown at high temperature when processed and canned, thus, rapid processing is necessary to retain appropriate quality of canned product. Canner peas are also picked at tenderometer readings of 95-105.
12. Smooth and Wrinkle-Seeded Peas:
The seeds of several varieties have absolutely smooth skin with high starch content as contrasted with the highly wrinkled skin of other varieties. The wrinkle-seeded varieties are generally regarded favorable due to their pleasant flavor and sweetness although the Marrowfat variety with smooth skin is also quite popular.
4. Climate Required for Cultivating Garden Pea:
Pea crop thrives best in cool weather and does not grow well in hot and humid weather. For its successful cultivation, it requires cool and moist climate having a temperature range of 7-21°C, but at maturity, it requires warm and dry weather. It produces satisfactory yield at an altitudes of 1500-1800 m above mean sea level. The crop is most productive in areas where rainfall is abundant.
Evenly distributed rainfall of 800-1000 mm per year maximizes pea production. Although pea can be grown successfully in areas of rainfall as low as 400 mm per year but in such areas of low rainfall the soil must be deep and capable of retaining moisture. Its seeds cap germinate at a temperature as minimum as 5°C but the most ideal temperature range for seed germination is 18-22°C, however, above 25°C temperature germination and growth processes get slowed down, and they get completely stopped above 35°C.
At higher temperature, the germination is undoubtedly rapid but plant stand is reduced possibly due to root rot caused by Fusarium oxysporium, Rhizoctonia solani, Pythium sp. etc.
The optimum temperature for growth, flowering, pod set, and further growth is 13-18°C. It cannot tolerate extreme high temperature since excessive heat disfavors the setting of pods and also retards the development of pods that have already formed and further reduces the size of seeds but the cultivar Alaska is comparatively tolerant to heat. The wrinkle-seeded cultivars are more sensitive to high temperature than smooth-seeded.
Plants are very responsive to temperature, especially during vegetative development. Pea plants, particularly leaves and stems, are tolerant to mild frost at early stages of growth but blossoms and pods are highly sensitive to frost at flowering stage causing heavy pod losses, and frost at pod setting stage produces deformed and discolored seeds.
Smooth seeded cultivars, especially those of field peas, have better cold tolerance than the wrinkled seed types. The temperature above 30°C affects the quality of canning pea as sugar content of peas is converted into starch. High humidity and rainfall affect pollination, fertilization, and setting of pods adversely. Pea crop is very sensitive to drought. Early cultivars are day neutral type, however, in late varieties, flowering is accelerated by long days.
5. Soil Required for Cultivating Garden Pea:
Pea is well adapted to a wide range of soils, but too heavy soils are not desirable for its cultivation because of their poor aeration and high water retention capacity. Good soil aeration is an essential condition for increasing the efficiency of nodule bacteria. Though pea is not a deep-rooted crop, it tends to be intolerant to shallow and poorly drained soils perhaps because of the increased incidence of root disease.
The yield tends to reduce when pea is cultivated in sandy and gravely soils that retain less moisture. The highest yield can be obtained when it is grown in loose, friable, and well drained heavy soils, like silt loam or clay loam, rich in organic matter and high in lime content and in which roots can penetrate deep.
Generally, sandy loam soils are preferred for early sown varieties and loam or silt/clay loam for late sown high yielding varieties. The organic rich soils are usually unfit for pea cultivation as their moisture reserve leads to excessive vegetative growth and poor pod formation. Pea crop is sensitive to both acid (< 5.5 pH) and alkaline (> 9.5 pH) soils.
It grows well on soils with moderate levels of calcium and neutral or slightly acid soils because optimum nutrient uptake takes place in slightly acidic (6.0 pH) soils, thus, for its successful cultivation, the soil pH must be in the range of 6.0-7.5. Pea does not do well in highly acidic soils when the pH is lower than 6.0 liming results in improved soil condition and crop growth, reduced root disease and improved yield, however, excessive liming of acidic soils may result in manganese deficiency since manganese becomes less available in alkaline soils.
Large concentrations of residual nitrogen in the soil, high salinity, and extremes of pH inhibit nodulation and nitrogen fixation. Pea crop affected by salt accumulations is especially vulnerable to disease attack.
The seed rate varies with variety, type of soil, time and method of sowing and soil moisture content at the time of sowing. Most of the pea varieties are single stemmed, thus, sufficient quantity of seed is used to maintain optimum plant-population density per unit area. Early season pea varieties are relatively less spreading that’s why require more seed in comparison to main season varieties.
For early and dwarf varieties, 100-120 kg and for main season varieties, 80-90 kg seed is sufficient for the sowing of one hectare area. Dwivedi et al. (1998) obtained maximum green pod yield with a seed rate of 80 kg per hectare.
6. Sowing Time of Garden Pea Seeds:
In northern plains of India, the main season crop is grown as a winter crop so the seeds of main season varieties are sown in the middle of October when the temperature prevails 20°-22°C and in hilly tracts as a summer crop for which the seeds are sown in the middle of March to the end of May, depending upon altitude, and in Peninsular India, the peas can be grown as early as in June-July, however, the sowings of early varieties, like Arkel and Asauji, start from August onwards.
Bhardwaj and Sharma (1996) obtained highest green pod yield from 15th October sown crop in HP and northern hill zone of Chhattisgarh, whereas, in Punjab, 5th November sown crop produced maximum number of pods per plant, pod length and number of seeds per pod.
Generally, flat seedbeds are used for raising pea crop. For better germination, pea seeds should be sown in soils having enough moisture. It is advisable to sow seeds in lines at a spacing of 30- 40 cm between rows and 5-7 cm between plants within the row for main season crop, however, the early varieties are sown thickly at a spacing of 20-25 cm row to row and 3-4 cm plant-to- plant to adjust more number of plants per unit area and to compensate yield losses due to their dwarf growth habit.
For both type of varieties, the depth of sowing is somehow maintained 2.5- 3.0 cm since too deep sowing will of course affect the germination and plant stand adversely, however, the depth of sowing in sandy and dry soils may be kept little bit more. In humid regions, it is advisable not to sow pea seeds at a depth of more than 5 cm to avoid rotting.
Pea intercropped with lettuce gave the maximum plant height, while pea intercropped with spinach gave the highest number of roots, root weight and root volume per plant. Pea intercropped with coriander gave the highest number of branches per plant, plant weight, mean shoot- root ratio and pea yield at Peshawar, Pakistan.
Pea being legume crop is capable of fixing atmospheric nitrogen into the soil, hence, the pea when grown in new field its seeds should be inoculated with nitrogen fixing Rhizobium bacteria. Prasad and Prasad (1999) reported the maximum nodulation with Rhizobium + phosphorus 90 kg/ ha + GA3 50 ppm producing 74.5 mg nodules per plant compared to 11.6 mg/plant in control.
For the inoculation of Rhizobium bacteria, the seeds are first mixed with 10% sugar solution and then Rhizobium culture packet is spread over the seeds and mixed thoroughly with seed so that the enough bacterial population may be maintained onto the seed, and thereafter, the seed is allowed to dry up in shade since direct sunrays, especially the short wave length part of the spectrum, are lethal to these inoculated bacteria, and later the inoculated seed is sown usually in the field.
If Rhizobium culture is not available, spraying crop with Cytozyme is very advantageous. It is also beneficial to inoculate the seeds with Azotobacter nitromonas if the crop is grown in acidic soils. This practice must be followed every year in order to ensure better germination and good yield. In general, soak the seed, especially of wrinkle-seeded varieties, in lukewarm water over night for better germination.
It is also advisable to treat the seed with recommended dose of fungicides, like Thiram, Captan, Foltaf, or Captafol etc., as an insurance against attack of soil borne pathogens. This treatment is very useful, especially for early sown crop, for the control of root rot disease of peas but special care is needed in the choice of fungicide to be used for the seed treatment and the timing and method of application to prevent potential toxicity to Rhizobium leguminosarum.
7. Manurial Requirement for Garden Pea Cultivation:
Adequate amount of each of the essential nutrients is indispensable for acceptable yield, as deficiency of an individual nutrient may result in poor pod quality, reduced pod formation, and reduced nitrogen fixation by root nodules, and an overall attenuation in plant growth and yield. On the other hand, excess use of nitrogenous fertilizer also produces adverse effect on nodule formation and the nitrogen fixation activity of nodule bacteria, with the result flowering is much delayed because of more vegetative growth and yield is reduced.
Under un-irrigated conditions, application of higher doses of fertilizers is not at all advisable. The condition of mineral nutrition, especially nitrogen feeding and the chemical nature of salts strongly affect symbiosis, however, the organic forms of nitrogen (urea) hardly reduce nodule formation, and soil humus in many cases has a stimulatory effect. The pea crop having abundant effective nodules seldom responds to the application of nitrogenous fertilizer because such application reduces nodulation and N2 fixation and delays crop maturity.
About 20 t/ha of well-decomposed farmyard manure should be incorporated thoroughly into the soil at least 15-20 days before sowing. Pea being a leguminous crop meets its nitrogen requirements from the air through symbiosis by Rhizobium leguminosarum bacterium, which lives in the nodules onto its roots but in initial stages, the pea crop may experience N2 deficiency prior to the induction of significant symbiotic N2 fixation due to insufficient nodules onto its roots, especially when the crop is sown in cool and wet soils.
This short of nitrogen at this stage can be corrected by placing a small starter dose of nitrogen (N2 30 kg/ha) fertilizer beneath at the time of sowing but not mixing with seeds. A small quantity of nitrogen as top dressing at flowering and pod formation stage increases pods yield.
Application of phosphorus is very essential as it stimulates the growth of root system and the activity of nodule bacteria in leguminous crops. It also reduces the harmful effect of the higher doses of nitrogen on the nodule formation process. Potassium has great influence on phosphorus metabolism. With sufficient supply of potassium in medium soils, the utilization of even low doses of phosphorus is increased.
Potassium has also been found effective to promote yielding capacity of plants and to increase fixation of nitrogen from atmosphere to soil. Depending upon initial fertility status, climatic conditions and variety, phosphorus 50-70 kg and potassium 50-60 kg/ha may be applied at the time of last ploughing. In pea like other legume crops, the method of fertilizer application is of great importance.
It is always advised not to mix the fertilizers with seed, as the direct contact of fertilizers with seed affects the germination adversely. The fertilizers should be placed in bands about 7-8 cm to the side and 2.5 cm deeper than the place of seed. When the machinery is not available for side placement, it is suggested that the fertilizer be drilled as a separate operation before planting.
For maximum yield and high nutrient concentrations in peas, Verma et al. (1997) suggested that nitrogen 15 kg and phosphorus 60 kg/ha were the optimum doses. Reddy et al. (1998) obtained the highest yield from pea crop with 10 t/ha vermicompost + 100% recommended NPK (37.5 : 60 : 50). Vimala and Natarajan (2000) reported a combination of nitrogen 120 kg, phosphorus 80 kg, Rhizobium 2 kg and phosphobactria 2 kg/ha as the optimum dose to obtain satisfactory yield and quality. Kanaujia et al. (1997) reported significant increase in yield and quality up to, 60 kg each of phosphorus and potassium.
Foliar application of 0.1% ammonium molybdate at flowering showed favorable effect on yield and quality of peas. Prasad et al. (1998) obtained the highest yield with foliar application of borax @ 2.5 kg/ha followed by soil application of 9.09 kg/ha borax. Dube et al. (2000) observed that biomass, economic yield, chlorophyll content, hill reaction activity, and activity of catalase and peroxidase decreased by iron lower or higher than 5.6 mg/litre.
Thapa et al. (2003) reported that zinc in the form of zinc sulfate at 0.2% positively affected most of the yield contributing characters and pod yield. The copper as copper sulfate and iron as ferrous sulfate were also effective on these crop characters. Higher concentrations of micronutrients showed detrimental effect on vegetative and reproductive growth leading to a reduction in yield of pea.
8. Irrigation Requirement for Garden Peas Cultivation:
Water requirement of peas depends largely on the agro-climatic conditions of the locality where the crop is to be grown. In general, the water requirement of pea crop is comparatively less, thus, can be grown without irrigation. In hills, it is normally grown as rain fed crop. At the time of sowing, the soil must have plenty of moisture, if the field is deficient in moisture pre-sowing irrigation is essential to apply for better germination of seeds and for further growth of plants.
Irrigation after sowing may also be given but it makes the soil structure compact and affects the germination adversely due to compaction of soil and formation of hard crust particularly in heavy soils. A light irrigation at flowering, pod formation and grain filling stage is of great significance, thus, care should be taken to provide irrigation at these stages. Irrigation must also be applied if there is scope of frost occurrence.
Excessive irrigation is always harmful to pea crop, as it leads to higher uptake of nitrogen, which causes excessive vegetative growth and thereby delays flowering resulting poor yield. However, irrigation at short interval is beneficial in sandy soils and dry areas where cultivation of pea without irrigation is not feasible. Most of the period of crop growth, the soil moisture should be maintained near optimum, hence, the irrigations should be so scheduled that the soil moisture is just sufficient for the crop.
Water logging or high soil moisture causes Fusarium wilt. Damage from water logging is on the whole more severe at warm temperature. Raina et al. (1998) applied drip irrigation at “V” volume of water and obtained significantly higher yield of pea (8.96 t/ha) as compared to surface irrigation (5.99 t/ha). Drip irrigation besides giving a saving of 32% water resulted in 49.5% higher yield as compared to surface irrigation. Malik and Kumar (1997) obtained highest yield with irrigation replacement of 0.75 or 1.0 PE.
9. Intercultural Operations of Garden Peas:
In leguminous crops, hoeing is an essential operation to provide better environment to the roots for their growth. Compaction of soil blocks aeration into the soil and affects the efficiency of Rhizobium bacteria to absorb nitrogen from the atmosphere as a result the plants show pale yellow color due to deficiency of nitrogen. On the contrary, loosening of soil improves aeration into the soil and efficiency of Rhizobium bacteria to absorb nitrogen from the atmosphere and to make it available to the plants for their growth and further development.
Pea crop is very sensitive to short exposure to anaerobic soil conditions, especially just before flowering and during pod filling stage. Hoeing is also necessary to remove the weeds, which compete with plants for nutrients, moisture, light, and space, and to conserve soil moisture for longer duration. A shallow hoeing is given 20-25 days after sowing. If the field is heavily infested with weeds, pre-emergence herbicides, like pendimethalin 1.2-1.5 kg a.i./ha or Alachlor (Lasso 50%) 0.75 kg a.i./ha or Tribunil 70% 1.0-1.5 kg a.i./ha may be applied 2-3 days after sowing seeds.
It is difficult to sow seeds uniformly, as they are sown directly in the field, so it is beneficial to provide proper spacing to the plants by removing extra seedlings as and when they are large enough to handle. Plant population beyond certain density level reduces the yield drastically.
Pea plants have the tendency to bear tendrils for climbing purpose. Thus, it is advisable to provide support to the plants of tall varieties with trellises or sarkanda sticks. If the plants are not staked properly, the plants get damaged during harvest time resulting in considerable reduction in yield but this system is applicable only on small scale, not on commercial scale, as it is impractical due to expensive affair. This operation is done when plants have attained a height of 10-15 cm. During staking, care should be taken not to damage the roots.
Staking is beneficial for getting higher yield but any delay in staking reduces the yield remarkably. It should be done parallel to the wind direction otherwise the wind blowing from perpendicular direction may damage the plants by uprooting the stakes along with plants.
10. Harvesting and Yielding of Garden Peas:
Early producing cultivars require as few as 1000 heat units to achieve maturity, whereas, late cultivars may require more than 1600 heat units. Green pea pods are ready for harvesting 3 weeks after flowering. The stage of harvesting is determined by visual observations taken over color, shape, size and filling of pods. The pods are harvested when they are well filled, tender, having high sugar content and start changing color from dark green to light green.
Any delay in harvesting turns the pods to poor quality due to conversion of sugar into starch, and this conversion takes place more rapid at high temperature. It is, therefore, advisable to pick the pods regularly without any delay. The pods deteriorate rapidly due to their high rate of respiration. Thus, harvesting should always be done in cool hours of the day. In most of the varieties, total three pickings are required. Care should always be taken to avoid injury to the plants while picking the pods.
Yield and quality both may not be harvested simultaneously due to having inverse correlation. The pods harvested before attaining full maturity will be better in quality but will be light in weight and will give lesser yield. On the other hand, the pods harvested at full maturity will be heavy in weight but poor in quality. The proportion of small pods decreases and yield increases as the harvesting is delayed. The quality of pea is associated with tenderness and sugar content. The tenderness decreases with the increase in starch content, which reduces the quality of pea.
The yield potential of pea crop is undoubtedly much greater than is actually realized. This is because not all plants per unit area survive and the surviving plants may not wholly realize their potential of pod and seed formation under a particular set of agro-climatic conditions. Date of sowing is very important factor influencing the yield.
Generally, pea is sown from the beginning of October to mid-November in the plains of northern India. The crop sown earlier or late suffers from wilt and mildew attacks, respectively. Hot dry weather interferes with pollination and seed setting, thus, affects the number of pods per plant, pod weight and lowers the quality of pods produced due to the conversion of sugars into hemicellulose and starch.
Staking is beneficial for getting higher yield but any delay in staking reduces the yield remarkably. Depending upon agro-climatic conditions and cultural management practices early varieties give on an average yield of green pods 30-40 q/ha and mid and late varieties 60-70 q/ha, and the dry grain yield varies from 150 to 200 q/ha.
Peas are highly perishable as they get heated easily in storage. Thus, a shallow container is desirable for their packaging. Unshelled peas keep better than shelled peas. Fresh unshelled peas can be kept for two weeks at 0°C temperature and 90-95% relative humidity. The shelled peas may be kept in frozen condition at -10°C temperature.
The over mature yellow pods, unfilled pods, diseased and insect damaged pods and trash should be removed before the peas are packed. In many cases, careful hand picking would eliminate the trash and defective pods. Peas are packed for marketing in baskets, gunny bags, and boxes of various types. It is important to have the container well filled so that it will not be damaged when it reaches market.
11. Cultivated Varieties of Garden Peas:
Pea cultivars vary greatly in size and shape of plants, pods, and seeds. Based on days taken from sowing to maturity, they have been grouped as early and mid-season genotypes. The early green pea strains become ready for first picking in 60 days, and there should be a second picking at an interval of 10-15 days. The early cultivars are poor yielding but are most remunerative due to high prices of green peas in early season.
Based on their growth habit, the varieties can be grouped into bush type, medium tall and tall type, and based on their seed shape they can be grouped into smooth (round) seeded and wrinkle-seeded type. Wrinkle seeded varieties are more tender, sweet flavored and of much better quality with high sugar content, and the sugar does not convert to starch rapidly, however, smooth seeded varieties have a starchy flavor even when young, that is why grown for harvesting as dry pea. Smooth seeded types are associated with rapid and higher starch accumulation and lower sugar content than wrinkle seeded types.
12. Controlling Diseases of Garden Peas:
1. Powdery Mildew (Erysiplie Polygoni DC):
The disease is of worldwide occurrence. The disease first appears on the leaves and then on other green parts of the plant. White floury patches appear on both sides of leaves as well as on tendrils, pods, and stems. These patches originate as minute discoloured specks from which a powdery mass radiates on all sides. When the attack has advances, large areas on the aerial parts of the host may be covered with these white floury patches. The superficial mass consists of the mycelium and spores of the fungus.
Early varieties suffer less than the late varieties. Generally, the varieties maturing in January escape the maximum intensity of the disease as they develop late in the season reaching its maximum intensity at pod formation stage. Verma and Sharma (1996) observed the maximum and minimum powdery mildew (Erysiphe gaminis) disease severity in late October and late November sown pea crops, respectively.
Sharma and Sharma (2002) also recorded highest incidence of disease on 15th October sown crop and minimum on 30th November sown crop in Himachal Pradesh. Unlike downy mildew, which flourishes in humid weather, it is worst in dry weather. Allied species or physiologic race of the fungus attacks bean, urd bean, lucrne, coriander, turnip, cabbage and many other plants of different families. The loss is proportionate to the disease intensity and varies considerably depending on the stage of plant growth at which the disease occurs.
In a hundred percent infected crop, the reduction in pod numbers is estimated to be about 21 to 31% and reduction in pod weight about 24 to 27%. Gupta and Shyam (1998) effectively reduced the severity of powdery mildew with spray of triadimefon (0.05%). Sharma et al. (2002) observed that Hexaconazole at 0.005% was highly effective in controlling the disease, while the highest pod yield was obtained in bitertanol treated plots.
i. Field sanitation is very important to check infection from the soil borne inoculum.
ii. Before sowing, treat the seed with hot water at 52°C.
iii. Spray Karathane, Calixin, Thiovit, or Sulfex at 0.2%, or Bavistin or Benlate at 0.15%.
2. Downy Mildew (Peronospora Pisi):
Scattered yellow to brown patches of indeterminate shape appear on the upper surface of the leaves and on stipules. They first appear on the lower leaves and then spread to upper leaves. The infected tissues soon die and turn brown. From the early stages of development of these spots the under surface, just beneath the discoloured area on the upper surface, is covered with a white to grayish violet downy growth of the fungus.
If the young stems are systemically invaded, they become distorted and checked in growth. This causes stunting of the entire plant. On pods, the disease is first seen when pods are green and flat. The patches are pale green, more or less elliptical, mostly on the sides or more irregular, elongated lesions gradually become brown. The seeds beneath the lesions are aborted and under sized.
i. Follow long crop rotation of 3-4 years.
ii. Seeds should be obtained from a disease free crop or from dry areas.
iii. Treat the seed with hot water at 52°C temperature for 30 minutes.
iv. Spray the crop with 0.2% Indofil Z-78 or Indofil M-45.
3. Root Rot (Rhizoctonia Solani, Fusarium Solani F. Sp. Pisi Jones and Pythium Sp.):
In early sown crops, there may be heavy losses of the plants due to root rot. Disease may develop at any temperature above 18°C but the optimum is 27-30°C. The above ground symptoms, which consist of poor growth, yellowing, and finally wilting of the leaves, are not well defined. The chief location of injury is the underground part of the plant.
On underground stem and upper portion of the taproot elongated, reddish brown, slightly sunken lesions are formed. They may extend to the secondary roots. The lower root system may be completely decayed and only the adventitious roots support the plant. Vascular reddish discolouration, if present, is only limited area.
i. At least four-year rotation should be followed.
ii. The crop should be planted when the soil has cooled and there is not very high soil moisture.
iv. The seeds should be treated with Thiram, Captan, or Bavistin @ 2.5-3 g per kg of seed.
v. Close planting should be avoided.
4. Collar Rot (Fusarium Solani F. Sp. Pisi):
Disease incidence ranged from 23.6-52.7%.
Seed dressing with carbendazim, Benomyl and Captan was inhibitory to the growth of the pathogen in vivo.
5. Fusarium Wilt (Fusarium Oxysporium F. Sp. Pisi (Linford) Synder and Hansen):
The earliest symptoms are seen at or after blossoming time. Plant growth is checked, foliage is yellowed and there is downward curling of stipules and leaflets. Upper part of the plant may be more rigid than normal. At first, the lower leaves and then the upper leaves show loss of turgidity. The entire plant wilts and the stem shrivels. Underground symptoms include destruction of feeder roots. Occasionally, the stem near the soil line is slightly swollen.
Yellow to orange and finally, black discolouration of the xylem vessels is present in the upper taproot and extends up the stem for several internodes after the foliage symptoms have appeared. The pathogen is seed borne as well as soil borne. In very wet soils, there is almost no infection but dry soils are most favourable for the disease. Verma and Dohroo (2002) observed lowest wilt incidence (5%) and highest disease control (94.37%) with 0.1% Bavistin seed treatment.
i. Follow long crop rotation.
ii. Grow resistant varieties like Alaska.
iii. Treat the seed with Benlate @ 2.5 g per kg of seed.
iv. Drench the soil with Bavistin at 0.2% concentration.
6. Near Wilt (Race 2 of F. Oxysporium F. Sp. Pisi):
The Race 2 differs from Race 1 in its higher temperature requirement for disease development. The symptoms of near wilt have much in common with those of wilt. Under favourable conditions, the fungus may cause damping off of seedlings. In older plants, a black canker begins to form near where the seed is attached, and it enlarges both upward and downward.
Finally, the entire outer part of the main root may be involved. The disease develops more slowly than the wilt, and the vascular elements are brick red rather than orange brown in colour. The discoloration commonly extends to the growing tip. The above ground parts of the plant are stunted, turn yellow or wilt and finally die. The pathogen may be seed borne to some extent but is mainly soil borne on crop refuse. It is destructive in wet soils.
i. Follow long crop rotations and proper field sanitation.
ii. Best method for avoiding losses from this disease is the use of resistant varieties.
iii. The disease can be managed by seed treatment with Thiram or Bavistin @ 2.5 g per kg of seed.
7. Rust (Uromyces Pisi):
Humid conditions favor this occurrence of disease; as a result, it becomes serious in pea. The diseased plants show yellowish, reddish brown, spherical raised pustules mainly on the lower side of leaves during December-January. The pathogen is mainly soil borne and survives in crop debris or weed hosts. The disease is spread by wind. Gupta and Shyam (1998) observed Hexaconazole (0.10%) and Difenoconazole (0.015%) effective for rust control.
i. Follow long crop rotation.
ii. Use disease free high quality seed.
iii. Destroy the weed hosts.
iv. Remove affected plants and disease debris from the field.
v. Spray the crop with 0.2% Indofil M-45 or Calaxin at 10-15 days interval.
It is seed as well as soil borne disease. Watery and olive green blisters on leaf bases and stems and water soaked oily spots on pods and leaves are the conspicuous symptoms of this disease. Creamy white slimy ooze can be seen on the lower surface of diseased lesions, which eventually turn brown and papery. The incidence is more severe on frost-injured plants.
i. Follow long crop rotation excluding legume crops.
ii. Use disease free seed.
iii. Avoid supply of excessive irrigation.
iv. Treat the seeds with 250 ppm Streptomycin solution for 2 hours.
v. Spray 0.01% Streptomycin at 8-10 days interval.
This is virus disease, which is transmitted by aphids, not the seed borne. The leaves of infected plant show chlorotic symptoms, i.e., green and yellow patches. The infected plants produce small outgrowth on lower surface of leaves. Retarded plant growth, curling and mottling of leaves, rossetting and pod distortion are the conspicuous symptoms.
i. Grow resistant varieties like Little Marvel in aphid prone areas.
ii. Rogue out and dump the infected plants.
iii. Spray the crop with the insecticides, like Dimethoate or Diazinon (0.3%), Monocrotophos (0.03%), or Malathion (0.1%) at 8-10 days intervals to control the virus vectors.