INTRODUCTION Potato (Solanum tuberosum L.) is one of the most important vegetable crop, belongs to an economically important family Solanaceae and is grown worldwide. In some countries like Bangladesh, it secured second position as a staple food crop after rice (Parveen et al., 2014). Due to its high nutritious value, the potato crop has gained much importance. It is considered as the third most important crop of the world after wheat and rice and is consumed by more than one billion people worldwide (Venkatasalam et al., 2013). In Pakistan it was grown on 172 thousand hectares during the year 2012 with the production of 3767.2 thousand tons which was 11.0 % more than last year (Economic survey of Pakistan, 2013). In Pakistan the production rate of the potato crop is very low compared to other countries due to the poor quality seed. Conventionally the potato crop is propagated vegetatively by seed tubers which give uniform growth and yield. The problem of deterioration of crop is faced due to virus infection and degree of deterioration changes from one crop to other and also to cropping seasons. The transmission of viruses is due to the planting of infected tubers. The prevalence of virus infection can reach up to 100% in successive crop seasons and can reduce the yield up to half or one third. This is the major problem faced by seed tuber producers. As discussed above the potato crop is usually propagated asexually by using tubers. The vegetative propagation in potato can