investigation on infection and distribution of beet yellows virus in razavi khorasan province

abstract beet yellows virus (byv), the type member of the genus closterovirus and one of the most economically important yellowing viruses, causes serious losses in sugarbeet. in order to study infection and distribution of beet yellows virus during summer 2007, about 530 samples were collected from beet’s fields in razavi khorasan province (fariman, torbate jam, ghoochan, chenaran, torbate heydariye, kashmar, neyshabour, mashhad). sampling was done in two ways: first, collecting leaves showing symptoms of vein clearing, yellowing and necrotic spots, and the other way, collecting samples randomly to determine distribution. all collected samples were tested by das-elisa and rt-pcr for detection of the virus. pcr products on %1 agarose, the band of 332 bp related to the virus was detected. results showed that, the highest and lowest infection rates belong to torbate heydariye with %17.8 and neyshabour with %4.8 respectively. infection was exist in all tested areas with different rates. the average rate of infection of byv in the province was %10.