Pyramiding and evaluation of both a foreign and a gene in the elite rice 9311.

Gene pyramiding is an efficient approach for the genetic improvement of multiple agronomic traits simultaneously. In this study, we pyramided two foreign genes, driven by the rice promoter, and (), driven by the endosperm-specific () promoter, into the elite cultivar 9311. These two genes were chosen in an attempt to enhance insect-resistance and Lysine (Lys) content. In the pyramided line, the foreign gene was efficiently expressed in the leaves and stems, and exhibited highly efficient resistance to striped stem borer (SSB, Walker) in the laboratory and rice leaf folder (RLF, Guenee) in the field. Furthermore, the gene was highly expressed in the endosperm and produced a remarkable increase of Lys content in the seeds of the pyramided line. The data from field trials demonstrated that most of the agronomic traits including yield were well maintained in the pyramided line compared to the parental control. These results strongly suggest that the foreign and genes have remarkable application potential in rice, and the resultant pyramided line serves as an ideal bridge material for the improvement of insect-resistance and high Lys rice in the future.