Rice (Oryza sativa L.), a cereal crop, plays an ultimately important role in the global food production. The occurrence of the rice disease and pest such as the rice blast (RB) and the brown planthopper (BPH) can seve-rely damage the safe production of rice, and the development and application of the resistant varieties can prevent the occurrence of the rice disease and pest economically and effectively, so the development of the resistant variety is crucial in the safe production of rice. In this study, we used the disease resistant line 75-1-127 carrying rice blast resistant gene Pi9 as the disease-resistant parent, the BPH-resistant line C4064 harboring brown planthopper resistant gene Bph18(t) as the BPH-resistant parent, and the elite restoring line Ce679 as recurrent parents, to hy-bridize, backcross, selfcross and field select for multiple generations. The Pi9-linked SCAR marker pB8 was used to select Pi9, and the Bph18(t)-linked marker KC16 was used to select Bph18(t) in the segregating populations. By molecular marker-assisted selection, evaluation of agronomic traits and assay of resistance, we developed restorer lines which pyramided Pi9 and Bph18(t) genes, and which demonstrated the similar level of resistance against rice blast and brown planthopper as compared with the disease-resistant parent or the BPH-resistant parent.

The present article summarizes the identification and nomenclature of physiological races,infection mechanism,causes of variation and status of researches on gene of rice blast fungus.The lack of researches on the problems existed in species identification,infection mechanism and identification and application of avirulence genes for rice blast fungus have been discussed.Some strategies have been suggested,such as cultivating identification species of rice blast fungus used unified in international,enhancing some other infection ways of rice blast fungus for above ground parts of rice seedlings,and the research of avirulence genes of rice blast fungus,etc.,in order to deepen and speed up the research of rice blast fungus.

The bacterial blight resistance gene Xa23 newly found in the wild rice was introgressed into the three elite restorer lines to lay a solid foundation for the development of the bacterial blight resistance varieties.The marker-assisted selection(MAS) and leaf-cutting inoculation method were used to assay new lines.The early generation breeding materials were assayed with the inoculation of P6,and the progenies of these resistant materials were verified by the marker C189,which was closely linked with gene Xa23.Of the 272 resistant accessions revealed by the inoculation method,only 254 accessions were verified to be resistant by the marker C189 test.The late generation breeding materials were stable in phonotype,and the elite lines could be selected for the variety trial.

Rice lodging is an important factor which has serious impact on the yield and quality of rice.The main factors which affect rice lodging are varietal differences,cultivation conditions,plant height and others.Thickness of stem wall was found to be closely related to lodging resistance,the content and composition of storage substances in stem plays decisive role in imparting rice lodging resistance.In addition,potassium,silicon and other elements are closely related to lodging resistance.Genetics research on rice lodging resistance has been discussed in the article,and it is pointed out that rice variety(line) with low lodging index should be selected as parents,especially hybrid combinations of two low lodging index coordinate parents and rice lodging resistance should be enhanced from the aspects of improving cultivation condition and strengthening variety breeding for lodging resistance.