Abstract
Potato is attacked by various diseases (bacterial, viral and fungal). PVX and PVY diseases Of potato caused by PVX (Potex virus X) and PVY (Poly virus Y) causes heavy losses to the potato crop. In Pakistan, potato crop losses were reported up to 83% due to viruses. Potato germplasm consisting of 28 genotypes was screened against the PVX and PVY under field conditions during two seasons 2008-10. In case of PVX eight genotypes i.e., 494055-40, FD9619, OCEANIA, FD48-4, TPS-9801 FSD RED, 394021-125, FD3713. showed variable response in both years probably due to their genetic instability and in case of PVY six genotypes i.e., FD1-8, FD9619, CARDINAL, DESIREE, TPS-9802, 393574-61 also showed different response might be due to variation of vector population or due to genetic instability. Out of 28 varieties/lines there were 3 varieties FD3-10, FD3-9 and 393574-61 found to be highly resistant against PVX. Only 3 varieties MIRRATO, ARTERIX and DESIREE were moderately susceptible while 8 were moderately resistant and 6 were found to be resistant against PVX. While in case of PVY out of 28 varieties/lines five varieties TPS-9801, FD32-2, OCEANIA, FD13 and FD3713 were found to be resistant against PVY and four varieties FSD RED, ARTERIX, ORLA and FD3-10 were susceptible. Four varieties were found moderately resistant, nine varieties were found moderately susceptible against PVY. In addition to field screening resistant source of potato was identified through biological and serological test (ELISA test) against PVX and PVY. Screening of different varieties of potato against PVX and PVY diseases to find resistant source to control the disease is an economical way and the results would help in the recognition of available resistant germplasm against the disease, and will be utilized for potato improvement program in Pakistan.