Studies on Sheath Blight Resistance and Biological Characters of Rice Variety ZH5 and Its Filial Generations

ZH5,an indica rice variety with good sheath blight(Rhizoctonia solani Kuhn)resistance,was crossed with three restorer lines Luhui 17,Duoxi 1 and GR8 with poor sheath blight resistance and their F1 and F2 progenies were obtained.From 2005 to 2006,the biological characters of the parents,F1 and F2 progenies were investigated,and their resistance to sheath blight was evaluated by artificial inoculation in rice paddy fields in Hangzhou,Zhejiang.The results indicated that the resistance levels to sheath blight of F1 progenies were between their female and male parents.Most of tested biological characters of F1 populations exceeded their parents or were between their parental lines.There existed a great segregation of sheath blight resistance among the individual plants of the same F2 populations,and there was also a big difference in disease resistance distribution of individual plants among different F2 populations.The correlation between the resistance to sheath blight and biological characters was not significant.The resistance level of sheath blight of rice varieties was mainly determined by their own genetic backgrounds.