• The aromatic compound in potatoes is dimethyl pyrazine.
• It is grown in all the states except Kerala.
• Late blight is the most devastating disease of potato.
• Late blight of potato occurs every year in the hilly areas but rarely occurs in the plains.
• Cyst nematode- Southern hills.
• Potato Tuber Moth – In the hot region of Maharashtra, Karnataka, and Madhya Pradesh.
• Wart disease is confined to the Darjeeling hills of West Bengal.
• Potato requires long photoperiod for growth and short photoperiod for tuberization.
• CPRI (Central Potato Research Institute, Kufri, Shimla) was established in the year 1949.
• Potato contains solanin 5 mg/100 g. If solanin exceeds 20mg/100g, it is unfit for consumption.
• Potato is self-pollinated.
• The maximum area under potato cultivation is in alluvial soil.
• The dormancy of potato tubers is 8-10 weeks.
• The seed plot technique in potato was developed by Dr. Puskarnath.
• Dehaulming is done in potato 10-12 days before harvesting (January).
• To break dormancy, tubers are treated with 1% thiourea + 1ppm GA3 for 1 hour.
• 40-45 grams of True Potato Seed (TPS) is sufficient for planting one hectare.
• It is the fourth major food crop in the world after rice, wheat, and maize.
• It originated in the tropical South America region and was probably brought to India by the Portuguese in the 17th century.
• India is second only to China in area and production.
• Major producing states include Uttar Pradesh, Himachal Pradesh, Gujarat, Madhya Pradesh, West Bengal, Orissa, Bihar, Haryana, Jammu, and Rajasthan. It has acquired importance as a cash crop as it is used in the processing industry to make chips, french fries, flakes, etc.
• Processing industries account for 2% of potato consumption in India for processing.
• Potato tubers can contain toxic alkaloids (solanine) when exposed to sunlight. This alkaloid can cause illness or death for both animals and humans. It is anti-scorbutic.
• Potatoes are used in making chips, halwa, gulab jamun, rasgulla, murabba, kheer, guzia, barfi, etc.
• It is an aperient, diuretic and galactagogue, nerve sedative, and gout stimulant.
• The leaves in extract form act as an antispasmodic in chronic cough.
• On burning with fire, grinding potato and applying its paste in the form of plaster gives good results.

Nutritive value (per 100g of edible portion)

Climate

• Potato is basically a cool season crop.
• It requires favorable environmental conditions such as low temperature, high light intensity, and short-day conditions for early initiation of tuberization and tuber development.
• Temperatures around 20°C day and 14°C night are ideal for tuber formation.
• Temperatures above 30°C completely inhibit tuber formation.

Soil and preparation

• Potato can be grown in sandy loam, silt loam, loam, and clay soil in friable, well-aerated, fairly deep, and rich in organic matter soils.
• Well-drained sandy loam and medium loamy soils are best suited for potato cultivation.
• Alkaline or saline soil is not suitable for potato cultivation.
• Potatoes are well suited to acidic soils (pH 5.0 to 6.5) because acidic conditions limit scab diseases.

Varieties

Time of sowing

• Early crop: 3rd week of September to 1st week of October
• Main crop: 1st week of October to 3rd week of October
• Late crop: 3rd week of October to 1st week of November
• In Hills: 3rd week of February to 2nd week of April

Seed rate

• Large size: 25-30 q/ha
• Medium size: 15-20 q/ha
• Small size: 10-15 q/ha

Dormancy

• Hilly tubers cannot be used immediately for the autumn crop as the tubers have a dormancy period of 2-3 months.
• Similarly, small potato tubers cannot be planted immediately after harvest and for an unknown period thereafter.
• The duration of dormancy in young potato tubers depends on the variety, time of maturity, growth conditions, storage conditions, and tuber size.
• The dormancy period of minitubers is longer than that of normal seed tubers.
• In these situations, breaking the dormant period is essential.
• Thiourea solution (Sodium Potassium Thiocyanate) @ 1-2% which is used as a treatment for cutting tubers for 1-1/2 hours and about 1 kg of thiourea is sufficient for 10 quintals of seed tubers or
• The tubers are placed in a 5ppm solution of GA₃ for 10 seconds. either
• Treat the tubers with an aqueous solution of thiourea for one hour and then dip them in a 2 ppm solution of GA for 10 seconds. either
• Ethylene chlorohydrin is used as a gas treatment. By mixing 6 parts water and 4 parts chemical, the tubers are kept in this solution for 5 days in an air-tight chamber and the temperature is kept at 70-80°F.
• Cold storage tubers germinate quickly if exposed to warm temperatures at 60°F for 10–14 days before planting.

Treatment of cut seed tubers

• Harvested tubers should be treated with 0.2% Dithane Z-78 which helps in improving tuber size and crop yield
• The cut pieces should be allowed to heal for 2-3 days at 18-21°C and 85-90% relative humidity which prevents rotting of the cut tubers as seeds (suberization/healing).
• If sprouts are coming out, do not treat the tuber with any chemical.
• To control scab disease, treat with Aglal (0.5%) for 5-10 minutes.

Sowing method: Potato is sown in two methods, which are given below.

1. Ridge and furrow method:

• The ridge and furrow method is the most popular method either by hand or mechanically
• Ridges are prepared in this method.
• The length of the ridges depends on the slope of the plot.
• Irrigation water cannot be supplied conveniently in very long ridges and furrows.
• Potato tubers are planted on ridges and irrigation water is given to the furrows.
• In hills, after composting in shallow grooves drawn with hand tools, the tubers are placed and covered with soil to form ridges. Care should be taken that the seed tubers should not come in direct contact with fertilizers.
• In the mechanical method, furrows are made with the help of 2-4 row maker-cum-fertilizer drills drawn by a tractor so that fertilizer can be applied in a sequence. The tubers are then planted with the help of a two-row planter cum ridger.

2. Flat Bed Method:

• It is generally used in areas with light sandy soil.
• The tubers are planted in very shallow furrows in flat beds.
• This method requires two earthing up; the First 30-35 days after sowing and the second 25-30 days after the first earthing up.

Planting distance

60cm x 15-20cm

Manure and fertilizers

• The potato plant is a heavy feeder and thus, requires high amounts of nutrients.
• During land preparation, apply 25-30 t/ha of well-rotten FYM or compost.
• It requires 100-150 kg of Nitrogen, 80-100 kg of Phosphorus, and Potash per hectare.
• A two-third dose of N along with a full dose of P and K is applied at the time of planting.
• The remaining one-third of the nitrogen is applied 30 to 35 days after planting, that is, at the time of the first soil application.
• Essential micronutrients like Bo, Zn, Co, Fe, Mn, Mo, etc. are sprayed when the crop shows deficiency symptoms.

Irrigation

Potato is a shallow-rooted crop that requires frequent light irrigation. Generally, irrigation should be given at an interval of 8-10 days in light soil and at an interval of 12-15 days in heavy soil. Light irrigation should be done when there is a possibility of frost. The critical stages for irrigation are germination, tuber formation, soil application time, and tuber emergence.

Mulching

• Mulching helps to retain soil moisture, reduce soil temperature and induce early germination.
• Locally available materials such as pine needles or leaf litter are very effective in controlling runoff losses and conserving moisture.

Weed Control

• Weeds are effectively managed by cultural or chemical methods or a combination of both methods.
• Weeds are effectively controlled by hoeing and weeding when the crop is about one month old and then earthing up.
• Pre-emergence application of Fluchloralin @ 1 kg/ha or Alachlor @ 1 kg/ha or Pendimethalin @ 1.8 kg/ha or Atrazine @ 1.0 kg/ha can effectively control the weeds.
• Paraquat @ 0.36 kg per hectare is also effective.
• Application of Tok-e-25 @ 2.5 kg per hectare after germination at about 2-3 leaf stage also helps in the management of weeds.
• The use of herbicides is generally not necessary in the potato crop because almost all the weeds are destroyed by earthing up operation, if any weed plants are growing on the ridges, they can be uprooted by hand.
• Pre-emergence application of Nitrofen @ 1.0 kg/ha or post-emergence Propenil @ 1.0 kg/ha mixed with 800-1000 liters of water can be used.

Digging / Harvesting

Early varieties mature in 80 days, medium in 90-100 days and late varieties in 100-120 days. Harvesting can be done by hand or with bullock or tractor-drawn diggers. Dehaulming is necessary when the crop is taken for seed production. Potatoes can be stored in cold storage at a temperature of 2-4^oC and 90-95% relative humidity.

Yield

• Early varieties: 20-25 t/ha or 200 q/ha
• Late varieties: 30-35 t/ha or 300 q/ha

Grading

Tubers are generally classified into 3 grades according to size and weight.

• Grade A (Large): Tuber weight more than 75 grams
• Grade B (Medium): Tuber weight between 50-75 grams
• Grade C (Small): Tuber weight less than 50 grams

Large-size tubers are in great demand for making chips.

Dehaulming

In potato production, dehaulming refers to the act of separating the above-ground vegetative part of the potato plant from the root tuber. Dehulling is one of the pre-harvest operations aimed at toughening the skin of the tubers and hence reducing the injuries at the time of harvest.

Despite its benefits and depending on the method of dehaulling used, this action can contribute to the spread of virus diseases such as potato leaf roll virus and potato virus Y (PVY).

There are three methods of dehulling, namely:

• Haulms Cutting
• Haulmes Drawing
• Paraquat Spray

Haulms cutting is a dehaulming method in which a sharp object such as a panga is used to cut off the vegetative part. This method of dehaulming allows the virus to spread from an infected plant to a healthy plant by cutting objects that carry infected plant sap.

Haulms pulling is a method of separating foliage from root tubers using hands. One hand is used to pull the leaf while the other hand holds the base of the leaf to prevent the tubers from coming out. This is the safest method of dehaumling, although it can be time-consuming in the production of seed potatoes.

Paraquat spray is a chemical method of destroying foliage. Once sprayed the chemical is absorbed into the plant system where it interferes with the physiological processes of the plant and eventually leads to its death. One drawback of paraquat spray as a method of dehaulling is that since the process is systemic (must be absorbed into plant tissue before action), it takes longer than other methods.

Physiological disorders

1. Hollow Heart:

• This is due to the rapid development of tubers.
• The tubers enlarge and remain hollow, causing a cavity in the center and the death of a small area of pith cells.
• This results in adjacent cracks and hollows as the center expands during potato development.

Management

• Maintain the soil moisture condition to an optimum level. Avoid giving excessive nitrogen.
• Grow varieties that are less prone to this defect.

2. Black Heart:

• This is due to sub-oxidation conditions due to potato storage in heaps as air does not move to the centre.
• It is also caused by high temperature and excessive moisture which results in the darkening of the tissue in the center.
• The appearance of tubers affects the consumers otherwise there is no decay.

Management

• Provide proper ventilation.
• Put potato tubers in layers. Do not store tubers in heaps.

3. Black Spot:

• It means internal browning of potato tubers.
• This occurs in vascular tissues within 3 days after mechanical injury.
• Phenols are related to black spots in potato tubers.

Management

• The genetic character of varieties.
• Provide proper storage conditions.

4. Greening:

• There are many factors that increase the amount of glycoalkaloids such as mechanical injury, premature harvesting, and excessive use of fertilizers or exposure to sunlight to produce solanine (>20 mg/100g) which is slightly toxic and the tubers remain green.

Management

• Proper earthing up on the tubers after tuberization. Keep the tubers in the dark after digging.

5. Knobbiness:

• It is due to uneven growth of tuber cells/tissues.
• Uneven water condition hinders tuber growth.
• Prolonged drought followed by heavy irrigation causes rapid growth of some cells, resulting in the formation of knobbiness.

Management

• Frequent and optimum irrigation should be done.

6. Cracking:

• It is caused by boron deficiency or uneven water supply

Management:

• Use Borax @ 20 kg/ha.
• Frequent and optimum irrigation should be done.

7. Sun Scalding:

• This usually occurs in the autumn crop when temperatures are high and there is more sunlight.
• Emerging sprout and leaves are highly affected at that time i.e. their tip gets burnt. This occurs when the temperature exceeds 30^o

Management

• Water should be passed through furrows to lower the soil temperature.

8. Translucent End:

• It is related to environmental stress and is caused by drought and heat.
• It is generally found at the proximal end of the tuber.
• The tubers appear glossy and are irregular in shape.
• It also causes decay in storage. These glossy areas are high in sugar and low in total soluble solids.

Management:

• Avoid excessive nitrogen supply. Maintain 50 percent moisture in the field.

9. Freezing injury:

• It is caused by exposure of tubers to freezing temperatures during or after harvest.
• It occurs at a temperature of -1.5^oC or less.
• The tissue becomes discolored and affects the vascular tissues on the ring which is called ring necrosis.
• When finer elements or cells of the vascular ring are affected, it is called net necrosis.
• This results in unmarketable tubers. Tubers show more damage towards the proximal end.

Management

• Avoid exposure of tubers to freezing temperatures during storage or harvest.

10. Sprouting:
    • This is often a serious problem in storage

Management

• It can be controlled by spraying Maleic Hydrazide @ 1000-6000ppm about 2-3 weeks before harvest.
• Chemicals like Chloro IPC (N-Tetra Chloro Isopropyl Carbonate) @ 0.5% and/or Nomyl/Amyl Alcohol @ 0.05-0.12mg/ha also help in preventing sprouting.

11. Swollen Lenticels:

• This disorder is caused by exposure of tubers to very wet conditions in the field or in storage due to lack of oxygen.
• Apart from giving an unmarketable appearance to the tubers, the major problem is that it becomes an entrance for pathogenic organisms, bacterial soft rot, pink rot, and leak.

Management

• Avoid over-watering. Avoid harvesting in low, marshy places in the field. Choose a field with good drainage.
• Avoid condensation in storage. Keep storage well-ventilated. 

Insect-pests

1. Cutworm (Agrotis ipsilon): They cut the sprouts from the ground level and feed only at night. They also attack and perforate the tubers.

Control: Soil application of Carbofuran 3G @ 15-20 kg/ha before planting.

2. Aphids (Aphis gossypii): Aphids suck the sap from the leaves and make them weak. The leaves turn yellow and turn downwards.

Control: Cut the stems (haulms) in the first week of January to avoid virus infection. Spray Imidacloprid 17.8 SL @ 0.5-0.6 ml/Litre on the crop.

3. Potato Tuber Moth (Phthorimaea operculella): It is a major pest of potato both in the field and in storage. It tunnels through potato tubers.

Control:

• Spray the crop with Bacillus thuringiensis (0.05%)
• Treat the bags used for storage with 10% neem kernel extract.

4. Hadda beetle (E. vigintioctopunctata): Both adults and larvae of this beetle feed on the skeletonization of leaves.

Control: Spray Malathion 50 EC at 1.5-2.0 ml/Lit of water.

5. Leaf-eating caterpillar (Spodoptera exigua): Caterpillars cause damage by feeding on potato leaves.

Control: Spray Malathion 50 EC at 1.5-2.0 ml/Lit of water.

6. Golden cyst nematode (Globodera rostochiensis): In India, this nematode is restricted only to the Nilgiri Hills of Tamil Nadu. Infected plants produce additional roots near the soil surface. Later, the outer leaves turn prematurely yellow and eventually die.

Control:

• Grow trap crops like marigold,
• Apply nemagon at the rate of 20-25 kg/ha to the soil, and
• Apply carbofuran 3G at the rate of 15-20 kg/ha.

Diseases

1. Early blight (Alternaria solani): The infection appears on lower leaves with necrotic spots having concentric rings. High moisture and low temperature are favourable for this disease.

Control: Spray the crop Indofil M-45 @ 2 g/ litre of water at 10-15 days interval.

Late blight (Phytophthora infestans): Irregular brown spots appear on leaves and stems. White downy fungal growth is visible on the lower surface of the leaves around the spots. Cloudy environment is favorable for this disease.

Control: Spray Blitox @ 2 g/Lit or Indofil M-45 @ 2 g/Lit of water.

3. Black scurf (Rhizoctonia solani): Infected plants die, stem canker may also develop. On tubers, black sclerotial bodies are formed. It is soil as well as tuber-borne disease.

Control:

• Treat seed tubers with agalol @ 0.3% for 5-10 minutes before planting, and
• Dip the tubers in 1% acetic acid containing 0.05% zinc sulphate before storage.

4. Charcoal rot (Macrophmina phaseoli): The disease is severe in late-maturing crops that withstand high temperatures above 28 °C. The fungus infects the tubers causing black spots on the eyes.

Control: Before storage, treat seed tubers with 0.25% Agallol-6 or Aretan solution.

5. Wart disease (Synchytrium endobioticum): It is a soil borne disease but confined only to the Darjeeling hills of West Bengal. A wart is a malformed, proliferated-branched structure that grows together into a mass of tissue.

Control: Soil treatment with copper sulphate or 5% formalin is effective.

6. Common scab (Streptomyces scabies): The disease mostly affects the tubers showing deeply pitted lesions of 1-2 cm diameter.

Control: Dip the tubers in Agalol-6 @ 0.25% solution for 5 minutes.

7. Black leg or soft rot (Erwinia carotovora): The base of the branch develops a black shriveled cortex and its growth is stunted. It attacks the tubers causing rot with foul smell.

Control: Treat seed tubers with 0.01% streptocyclin solution before planting.

8. Potato leaf roll virus: Affected plants become stunted, more upright, and thinner than normal. Leaves take on a rolled, leathery texture. It is spread by aphids.

Control:

• Remove weeds around potato fields, and
• Adopt control measures for aphids.

Seed Plot Technique

• The use of healthy seeds is very important in vegetatively propagated crops like potato.
• Continuous use of the same seed stock year after year without periodic replacement allows diseases (viruses) to infiltrate.
• These viruses are easily spread by leaf and root contact in the field or away from the field or through aphid vectors within the field.
• Viruses are responsible for reducing the yield potential of infected tubers.
• High mountains were a traditional source of healthy seed because of the low temperatures that keep aphid populations low.
• However, the area under potato in the hills is only 5% and this was not sufficient to meet the seed requirement of the plains.
• In 1962, Cockerham (Scotland) came to India to do some studies to increase the yield of potato.
• The seed plot technique in potato was developed by Dr. Puskarnath.
• Based on the data on aphid presence and buildup in different months, it was found that potato can be successfully grown under low or no aphid conditions in many parts of the plains for seed production.
• This led to the development of “seed plot technology”, i.e. growing healthy seed crops during low aphid population periods available in the northern plains.

Steps to be followed in Seed Plot Technique:

• Should be sown before the start of 10th October.
• For small-sized potato tubers, sow at a closer distance of 45 cm x 15 cm.
• At least two inspections should be made during the growing season to weed out any diseased or off-type plants.
• Use granular systemic insecticides at planting or tilling.
• By the middle of December, when the crop is well formed, stop irrigation and later stop it completely.
• The haulm should be cut before the aphid population builds up to 20 aphids per 100 leaves, in late December or the first week of January.
• If the crop is still green, destroy haulms by spraying 2% solution of CuSO₄ or cutting them.
• Tubers are harvested from mid to late February

Amendment

• Cultivation in hot weather and green manuring.
• Use of crop rotation for 2-3 years.
• One or two sprays of systemic insecticides + spray of Metalaxyl or Mancozeb in December-January.
• Treat tubers with 3% boric acid for 30 minutes after harvest and before storage of produce.