Indian Journal of Virology

In potato cultivation, tuber seed is the single most important factor influencing yield of the crop. It costs nearly 50 per cent of the cultivation hence the seed stocks need to be free from any varietal mixture and viruses and virus-like pathogens. Potato is infected by almost 40 viruses but only 6 to 8 are important from the crop and seed production angles. In the end of 18^th century many farmers in Europe had to abandon potato cultivation because of severe attack of some unknown disease with leafroll symptoms (probably including mosaic and crinkle diseases) causing severe yield reduction. Therefore, the Dutch crop scientists devised a Seed Certificateion Scheme in 1908 in Netherlands which followed in USA in 1914 and in 1918 in Scotland (UK). The tuber transmission of potato leaf roll virus was discovered in 1917 and thereafter many potato viruses causing mosaics were discovered. Methods of field inspection were fixed and called Seed Certification. Until 1938, India was importing seed potato from U.K. After the import of seed was banned, scientific seed production and certification in India was initiated by HP Government in 1946 at Shilaroo Potato Seed Farm. CPRI was established in 1949 which started production of potato varieties and breeders' seed. Based on surveys for aphid population on potato crop, initially only higher hills were considered fit for seed production. Later on the western and central Indo-Gangatic plains also were found suitable for potato seed production during October to December/January. This laid the basis for multiplication of seed potatoes in India through ‘Seed plot technique’ (SPT). Breeder's seed scheme was therefore initiated by CPRI in 1967. Thereafter, area under seed and table potato enhanced gradually and consequently the cold storage capacity. Official potato Seed Certification by the State Govts. was started in 1970. The seed production initially depended on visual inspection for clonal selection and then biodiagnosis for several years. Now it employs advanced serological, EM and molecular diagnostics for tuber indexing ensuring high quality of virus free nucleus/breeders' seed. Besides, it also became possible to employ these techniques for confirming virus-freedom in material under quarantine and for virus eradication through meristem culture. Rate of field multiplication is usually 1: 5 hence in vitro micro-tubers/plants are being integrated to reduce number of field multiplications and enhance the total breeder's seed production. Today area under potato cultivation in India is 1.3 million/ha thus national seed requirement @ 3.0 t/ha comes to 3.9 million tonnes. The Institute produces ca. 3000 t breeders seed annually. This seed is supposed to be multiplied upto 5 years (3 cycles as FS1, FS2 and certified and two years with farmers) with multiplication rate of 5 times each year (5x5x5x5x5 = 3125) upto certified stage C2, hence the total seed produced will be 9.37 million tonnes which is more than double the national seed requirement making the country self sufficient and saving above Rs. 1900 crore or US $ 384 million p.a. on import of seed like our neighbouring countries. SPT also revealed the worth and potential of Indian potato varieties. This is why Indian potato varieties were also accepted abroad and now India exports both table and seed potatoes. Details of the system, its implications and advances made, etc. will be discussed.