Resistance to Rice Blast by Clustering Analysis of Primary Core Collection of Chinese Rice Germplasm

Resistance to rice blast of the primary core collection of Chinese rice germplasm(including 203 accessions) was evaluated.Among the 203 rice accessions,41.38% and 78.82% were resistant to leaf blast and panicle blast,respectively.Twenty-eight varieties(13.79%) showed resistance to at least 70% races of Magnaporthe grisea(Hebert) Barr,with 66.50% of the tested varieties resistant to 20%-70% races of the pathogen.According to the correlation analysis,resistance spectrum of the varieties in seedling stage was significantly correlated with leaf blast resistance at the 0.01 probability level(r=-0.362 4,P0.000 1)but not with panicle blast resistance.Leaf blast resistance was aslo not significantly correlated with panicle blast resistance.According to the results of clustering analysis,japonica rice varieties from the primary core collection could be classified into seven groups.Fifteen varieties including Xugunuo,fallen assigned 7 groups.The group 3 were resistant to the races of C,D,E and F with resistance spectrums from 68.8% to 87.5%.For indica rice,twenty-six vareties belonging to group five(six groups in total)were resistant to races of E,F and G with resistance spectrums from 50.0% to 87.5%.