Abstract: The resistance of a total of 211 samples of Pyrus germplasm accessions belonging to
eleven species to Valsa canker were evaluated by inoculating detached shoots in the lab with conidial
suspension and mycelia plugs of two strains of Valsa mali var. pyri. The results indicated that the
difference between the disease auti-invasion（17.5%）and auti-expansion（35.1%）was significant among
the examined germplasm accessions. The disease auti-invasion and auti-expansion of the same germplasm
accession in response to the pathogen was significantly different，and the consistent resistance accounted
for 30.3% while the inconsistent 69.7%. For all of the germplasm accessions，highly resistant（HR/HR），
resistant（R/R），moderately（M/M），susceptible（S/S），and highly susceptible（HS/HS）of the disease
auti-invasion and auti-extension to the pathogen was 1.4%，4.7%，12.3%，10.9% and 0.9%，respectively.
According to comprehensive evaluation for the resistance，it was considered that of Daxiangshui，Duli，Jiangdao，Le Counte，Longquansu，Pingguoli，Shanli，Yunhong-1，Zaoyu and Changshilang were resistant
（R/R），that of Niitaka，Wudou-9 and Jingdu-3 were high resistant（HR/HR）and that of Xinxing and
Xinhuang were high susceptible（HS/HS）.

Key words: Pyrus, germplasm accessions, Valsa canker, evaluation for the resistance