HOST GENES AND TRANSGENES THAT CONFER RESISTANCE TO A SCOTTISH ISOLATE OF POTATO LEAFROLL VIRUS ARE ALSO EFFECTIVE AGAINST A PERUVIAN ISOLATE

Potato genotypes with host gene-mediated resistance (host-MR) and coat protein-mediated transgenic resistance (CP-MR) to potato leafroll vir us (PLRV), were inoculated with a Scottish and a Peruvian isolate of P LRV. The coat protein transgene had been cloned from the Scottish PLRV isolate which had also been used during the screening and selection o f genotypes with host resistance. Significantly less PLRV accumulated in plants with either host-MR or CP-MR than in plants of susceptible g enotypes or in non-transformed control plants, but the two forms of re sistance were equally effective against both PLRV isolates.