Potato Solanum tuberosum L.   The potato, a native of South America, occupies the largest area under any single vegetable in the world. It has a special value as food. The consumption of potato per head is very low in India compared with that in Western countries. Potato belongs to the family Solanaceae, genus Solanum and species tuberosum.

VARIETIES.   The potato having continued under cultivation in India since the seventeenth century, there are some old varieties, like 'Satha', 'Gola', 'Phulwa', 'Up-to-date', 'Darjeeling Red Round', 'Craig's Defiance', 'Great Scot' and 'President', which are still cultivation. The Central Potato Research Institute, Simla, has released a large number of improved varieties.

'Kufri Red' - An improvement upon DRR, suitable for the plains of Uttar Pradesh, Bihar and Bengal.
'Kufri Kuber' - Suitable for both the plains and hills of Punjab, Bihar and Maharashtra.
'Kufri Kisan' - Late-maturing, particularly suitable for Punjab, Delhi, Uttar Pradesh and Madhya Pradesh.
'Kufri Kundan' - Like 'Up-to-date', suitable for the hill areas and for places where the soil is heavy and wet.
'Kufri Safed' - Late, an improvement upon 'Phulwa', suitable for poor soils.
'Kufri Kumar' - Resistant to late blight; recommended for the hills and plains.
'Kufri Neela' - Late, an improvement upon 'Great Scot', resistant to late blight; recommended for the Nilgiri Hills.
'Kufri Sindhuri' - Of medium maturity, can replace 'Kufri Red'; recommended for the plains.
'Kufri Chandramukhi' - Early, degenerates slowly, keeps well in storage; high-yielding.
'Kufri Khasi-garo' - Early, with good resistance to late blight; with moderate resistance to early blight and viruses; fit for growing in the hilly regions of Assam.
'Kufri Naveen' - Possesses field resistance to late blight and wart.
'Kufri Chamatkar' - Early, suitable for Punjab, Delhi, Haryana, Uttar Pradesh and Madhya Pradesh.
'Kufri Neelmani' - A replacement for 'Great Scot' in the Nilgiri Hills.
'Kufri Sheetman' - A frost-resistant variety; suitable for Punjab, Delhi, Rajasthan, Haryana, Uttar Pradesh and Madhya Pradesh.
'Kufri Jyoti' - It possesses high resistance to late blight and wart; suitable for Himachal Pradesh.
'Kufri Alankar' - A very early, high-yielding, photo-insensitive variety, suitable for the plains of northern India.
'Kufri Jeevan' - A late high-yielding variety, possessing resistance to late blight, wart and Cercospora leaf-spot; recommended for Himachal Pradesh.

CULTIVATION.   Potato tubers are planted either whole or cut into pieces. Diseases-free certified seed should be sown. The seed weight varies from 800 to 1,500 kg per hectare according to the size of the seed-tuber. In the plains of northern India, the sowing time is from the middle of September to the beginning of January. Two successive crops can be raised on the same land. In the Nilgiri Hills, three crops are raised in succession in April, August and January. In the hilly regions of the north, the crop is sown in March-April. A spacing of 45 to 60 cm X 15 to 25 cm, according to the variety and the size of tuber is adopted.

Potato needs irrigation at frequent intervals, depending upon the soil and climatic conditions. Usually, 6 irrigations are sufficient. Chemicals, such as Linurion or Simazine, at 0.5 kg per hectare applied as a pre-emergence spray are effective in controlling weeds. Potato is harvested from the time it is of sufficient size until the vines are fully ripe. The average yield varies from 20 to 30 tonnes per hectare. The best method of storing potato is in cold stores at 2.2^oC to 3.3^oC and at 75 to 80% relative humidity. When stored in a room, good ventilation should be provided.

Aphids, jassids and cutworms are the most important insect pest of potato. They can be controlled by spraying Malathion, Folidol, DDT and Endrin. Important diseases attacking potato are early, and late blights and virus diseases, A, X and Y and leaf-roll. Charcoal-rot is the most serious storage diseases. The seed-plot technique consists of the sowing of tubers before the middle of October, the killing of haulms by the end of December before the aphid population builds up, and harvesting by the end of February or in the beginning of March. Two inspections made to rogue out any diseased or off-type plants, along with the adoption of the above techniques will produce disease-free seed.