Chromosomal location of genes for spikelet number of the giant spike wheat germplasm

Progresses in research on brown planthopper resistance gene in rice are reviewed in this paper. Brown planthopper is one of the most severe pests of rice crop over the world. Brown planthopper overwinters in the tropics and immigrates to the temperate rice regions. Insects of brown planthopper gather at the base part of rice plant and suck assimilates from the phloem. When the rice variety is susceptible, hopper burn usually is resulted. Brown planthopper is also the vector for several rice virus diseases. In experiments on resistance gene, the phenotypes are evaluated by artificial test to get repeatable results. The commonly used evaluation methods include the standard seedbox screening technique,tiller seedbox screening technique, and honey dew test. Under the selection pressure of resistant variety for several years, a new biotype of brown planthopper comes out that can overcome the resistance of the variety. Exploring new resistance gene is critical for developing resistant rice variety. Up to now, hundreds of resistant germplasm have been screened for brown planthopper resistance and more than 10 of major resistance genes and many QTL have been detected. There are many papers that report mapping of brown planthopper resistance genes by molecular markers. In the future, isolation of brown planthopper resistance genes will be most important subject in the future.