Resistance Evaluation of Dominant Varieties against Rice Blast (Magnaporthe oryzae) and Bacterial Blight (Xanthomonas oryzae pv. oryzae) in Guangzhou, China

The resistance of dominant rice varieties in Guangzhou against rice blast(Magnaporthe oryzae)and bacterial blight(Xanthomonas oryzae pv.oryzae)were evaluated by artificial inoculation and field natural blast nursery identification.Among 11 varieties tested,seven varieties showed resistance to rice blast,accounting for 63.6%;two varieties were highly resistant,accounting for 18.2%;three varieties were resistant,accounting for 27.3%;two varieties were moderately resistant,accounting for 18.2%;four varieties were susceptible(moderately susceptible),accounting for 36.4%.Varieties showed different resistance against the prevailing pathotype IV of bacterial blight;one variety was resistant,accounting for 9.1%;three varieties were moderately resistant,accounting for 27.3%;five varieties were moderately susceptible,accounting for 45.5%;one variety was susceptible,accounting for 9.1%;one variety was highly susceptible,accounting for 9.1%;all varieties tested showed susceptible to the virulent pathotype V.Huanghuazhan,Yuejingsimiao 2 and Fengxiuzhan showed resistance against both bacterial blight(pathotype IV)and rice blast,accounting for 27.3%.It is helpful to reduce the production risk by extending such dominant rice varieties with good resistance to rice blast and bacterial blight.