Introduction


 

Potato is one of the world's most important non-cereal high yielding horticultural food crop, which is native of Peru-Bolivia in the Andes (South America) and seems to have been introduced in India from Europe by Portuguese in the early 17th century. Initially, it was established as an important cool season crop in the hills as well as plains but, now it is being cultivated in almost all the States of India under different agro-climatic conditions. India has taken a giant leap in terms of potato area and production since independence. Compared to 1949-50, the year of establishment of CPRI, when the total production was 1.54 million tones from an area of 0.23 million ha, we now produce about45 million tones of potato from about 1.9 million ha area. There has been a phenomenal increase in area, production and productivity over the last six and half decades. India is the second largest producer of potatoes in the world. In terms of area, India ranked third in world after China & Russian Federation (FAO, 2013). The futuristic upward trend in potato production in India will mainly be due to a rapidly emerging processing sector. India has the potential to achieve the targeted expansion of potato area up to 2.55 million hectare and the production to about 69 million tones by the end of 2030 (Vision 2030, CPRI). Potato being a vegetatively propagated crop is subjected to large number of seed-borne diseases responsible for degeneration of seed stocks over the years. It is therefore imperative to use good quality seed for economic production. Till 1935, the seed potato was being imported from various European countries on yearly basis, but during Second World War, European countries put a blanket ban on the export of potato seed to India. Therefore, Imperial Agriculture Research Institute started potato breeder seed production scheme at Shimla and Kufri during 1935. It was the beginning of seed potato industry in the country.

The seed potato from the hills used to be dormant for planting in the plains, therefore, either the dormancy was broken artificially or the system of late planting, somewhere in last week of December, was adopted to grow late winter or spring crop of potato. The spring crop was exposed to high population of aphids leading to very high viral infestation resulting in poor productivity in the subsequent generations. In addition to this, the area under potato was quite marginal in the hills. It was therefore not possible to feed large area in the plains. Therefore, intensive surveys were made in the plains to find out vector free/low vector period suitable for potato seed production. This laid the foundation of development of “Seed Plot Technique” in 1959 which helped production of good quality seed in the plains so as to meet the bulk seed requirement for ware potato production in the sub-tropical plains. This technique drastically improved the health standard of seeds produced in plains. During the first three decades of the inception of CPRI (1958-59, 1968-69 and 1978-79) a linear increase in area, production and productivity could be achieved largely because of the seed plot
technique and improved varieties. The seed technology research and innovative quality seed production programme by public and private sector has played a vital role in potato revolution in the country. All neighboring countries viz., Pakistan, Bangladesh, Nepal and Sri Lanka import seed from The Netherlands, paying very high price. Seed Plot Technique not only benefited our farmers, but the country also saved millions of rupees on foreign exchange which would have gone for purchase of costly seed from foreign countries. The varieties released before 1963 ran out quickly because small quantities of seed were released to State Departments and progressive farmers, without linking them with the production of disease-free seeds at the field level. It happened primarily because of low multiplication rate of potato seed, which is as low as 1:5 per generation. Because of high seed rate (25-30 q/ha) and low seed multiplication rate, newly released potato varieties took very long period for reaching the farmers' field. This necessitated a technology for faster multiplication of healthy seed of the released potato varieties in sufficient quantity. Moreover, very stringent quality control was required to maintain the health status of the vegetatively propagated crop like potato. Therefore, a well organized scientific strategy of breeder seed production was envisaged  in 1962-63 and thereafter involving clonal selection, tuber indexing and stage-wise field multiplication of healthy indexed tubers in subsequent four generations. Indexing of tubers against contagious and insect transmitted viruses is done by ELISA against PVX, PVS, PVM, PVA, PVY, and PLRV. Crop inspection, roguing of diseased plants and immuno-diagnosis are the regular features of the programme to improve the seed quality. The breeder seed produced by CPRI is supplied to various state govt. organizations for further multiplication in three more cycles' viz., foundation-1, foundation-2 and certified seed under strict health standards. However, the current status of breeder seed multiplication by the state governments is not as per the desired seed multiplication chain. The state govt. organizations multiply the breeder seed only upto Foundation-1 and producing about 15,600 tones potato seed in the country. This way there is huge shortage of certified seed in the country. The conventional system of seed potato production has limitations like i) low rate of multiplication ii) requires more number of disease free propagules in the initial stage iii) development of 100% healthy seed stock from infected material is slow and time taking iv) progressive accumulation of degenerative viral diseases in each field exposure and, v) several field multiplications of initial disease-free material (7 years). The only way-out to overcome the above said limitations is augmentation of seed production through hi-tech/ micro-propagation system to improve the quality and to reduce the field exposures. Therefore, Central Potato Research Institute is gradually shifting from conventional system of seed production to hi-tech seed production system. Potato has readily responded to the totipotent nature of plant tissues in micropropagation and it has become easy to export/import disease free planting material in tissue culture form without any risk of importation of deadly diseases. The process of micropropagation has become much more important in the case of potato for the purpose of production of disease-free plants from infected one. There is a tremendous scope to increase healthy seed production vertically by adopting aeroponic technology where increase in multiplication rate from 5:1 to 50:1 can be achieved. We do not need any excess area for aeroponic based healthy seed production. Only one percent of conventional water usage is required which is basically recycled water. It is the ideal technology for cost-effective production of quality seed in the present era. The adoption of high-tech seed production technologies developed by the Institute has led to opening of more than 20 tissue culture labs in private sector throughout the country. Advantages of this system are i) tropical states which do not have isolated and virusfree potato growing areas can also produce quality seed ii) early supply of nucleus seed to commercial growers by reducing the number of field exposures iii) improved tuber quality and reducing the load of degenerative diseases iv) utilize the resources and trained manpower round the year and v) vertical growth and reduction in pressure on land. By 2030, 6.38 – 7.65 million tones of certified seed will be required to plant the projected area of 2.55 million ha. Considering the seed replacement by farmers every fourth year, atleast 2.0 million tones of certified seed would be required by the year 2030. Presently, Central Potato Research Institute is producing about 3000 tones of breeder seed per annum. If this quantity of breeder seed is multiplied in three cycles (foundation 1, foundation 2 and certified) approximately 0.65 million tones of certified seed can be produced that would satisfy only 33% of seed demand. Incorporation of hi-tech seed production system coupled with advance virus detection techniques can be the only way out in fulfilling the huge demand of quality seed potatoes in the country as well as in achieving the projected targets for the year 2030.