Gene Pyramiding to Improve Green Super Rice by Molecular Marker-aided Selection

Hybrid rice was first cultivated in China in 1976 and now its planting area has expanding to more than 15 million ha annually. In recent years, however, the hybrid has shown several major problems in rice production including: the loss of resistance to diseases such as bacterial blight and fungi blast, in addition to its relatively poor cooking and eating quality. There is also urgent need for improving its resistance to insects such as stem borers and planthopper, as they frequently cause damage to the crop. A series of works were conducted in order to solve the above problems: (1) Xa21, Xa7 and Xa23, three wide spectrum BB resistance gene, were introgressed to the restorer Minghui 63 and 9311 by molecular marker aided selection to improve its resistance to bacterial blight. (2) Two genes, Pi1 and Pi2, showing broad-spectrum resistance to fungi blast, were introgressed into Zhenshan 97. Another broad-spectrum blast resistance gene, R6, which was introgression to Y58S and Guangzhan 63S, respectively, by backcross and anther culture to improve their blast resistance by molecular marker-aided selection. (3) Three genes, Bph14 and Bph15 and Bph18, all of them are highly resistant to brown planthopper, were introgressed to Zhenshan 97, Minghui 63 and 9311 to improve their BPH resistance. (4) The following cloned quality genes, such as GS3, Wx, alk and fgr et al, were also used to improve the hybrid rice and increase their quality. The above versions of the lines can be combined in various ways to make the green super hybrids to meet the need of rice production.