IDENTIFICATION OF STRAINS OF TOBACCO MOSA IC-VIRUS (TMV) ISOLATED FROM CAPSICUMS IN SOUTH-CENTRAL CHINA

To differentiate tobacco mosaic virus (TMV) strains in southcentral Ch ina, strain identification of TMV isolates collected from fields of sw eet peppers or chillies in the cities of Shanghai (30 degrees N), Wuha n (30 degrees N), Chengdu (30 degrees N), Lhasa (30 degrees N), and Da li (25 degrees N) was performed by using the series of TMV-resistant C apsicum spp, carrying the genes of L+, L-1, L-2, L-3, and L-4, respect ively. As anticipated, no isolates were identified as Po strain, becau se all of the TMV isolates were collected from cultivars with a L-1 re sistance gene. On the other hand, it was found that the P-1 and P-1,P- 2 strains which can infect cultivars with the L-1 resistance gene were widespread in southerncentral China. In addition, the P-1,P-2,P-3 str ains which can break down the resistance of cultivars with L-3 resista nce gene was also detected in Shanghai. No isolates were capable of in fecting C. chacoense Jacq. harbouring the L-4 resistance gene. Based o n the study of the variability of TMV strains in China, methods for th e breeding of sweet pepper for TMV-resistance were evaluated.