Identification Of Quantitative Trait Loci Associated With Small Brown Planthopper(Laodelphax Striatellus Fallen) Resistance In Rice And Preliminary Study On Identification Method For Rice Black-Streaked Dwarf Disease

The small brown planthopper (SBPH) is an economically important pest in rice (Oryza sativa L.) and distributes widely in China. It not only causes direct damage by sucking plant sap which caused plants leaves yellow or withered and rice grain weight down and rice quality reduced but also transmits several viral diseases such as rice stripe virus (RSV) and rice black-streaked dwarf virus (RBSDV). In recent years, RSV and RBSDV which caused by SBPH feeding and transmitted by this planthopper often cause major yield losses and have been increasing in China to be the most serious disease of JAC rice area. Resistance gene mapping and then marker-assisted selection (MAS) breeding, which greatly speeded up and improved cultivation of resistant varieties, has been considered as the most cost-effective method to control planthoppers.We found that indica rice variety IR24significantly resistant to the planthopper through study for years. In this study, a recombinant inbred line (RIL) population and two thromosome segment substitution line (CSSL) population derived from the cross of A.sominori (japonica) and IR24(indica) were used to detect QTL controlling resistance of planthopper. CSSL1were a series of IR24chromosome segment substitution lines in Asominori background, and CSSL2were a series of introgression lines of Asominori in the background of IR24. We identify IR24with seedbox screening test, antixenosis test and antibiosis test. We found that the resistance of IR24derived from patience and antixenosis. From seedbox screening test, one QTL were detected on chromosome7in RIL population. Three QTL were detected on chromosome8,11and12in CSSL1. Two QTL were detected on chromosome3and8in CSSL2. From antixenosis test, two QTL were detected on chromosome11and12in RIL population. Two QTL were detected on chromosome7and9in CSSL1. One QTL were detected on chromosome3in CSSL2. Among them, the QTL tightly linked maker X249in chromosome3was detected with seedbox screening test and antixenosis test, indicating that the resistance locus can be stably expressed. The QTL tightly linked maker X278in chromosome8was detected in CSSL1and CSSL1, indicating that the resistance locus can be stably expressed, indicating that they are the same QTL or resistant gene cluster.Rice black-streaked dwarf disease which transmited by SBPH occurred seriously in recent years caused a significant reduction of rice production. At present, RBSDV has replaced RSV to be major rice disease in Jiangsu Province. There are no anti-RBSDV varieties in production in large scale. The study of resistance of rice black-streaked dwarf disease is late. There is not yet an effective resistance identification method of rice black-streaked dwarf disease. In this paper, we use frozen rice plants of RBSDV feed planthopper then we study factors affecting the efficiency in transmit virus. We optimized these factors in order to establish resistance identification method of rice black-streaked dwarf disease. The result can also provide the most reliable experimental evidence for the mechanism of the disease.We found that the amount of SBPH and the age of SBPH significantly affected efficiency in transmission of RBSDV. Increasing the amount of SBPH and using the one to two instar nymphs of SBPH is effective means to improve the efficiency in transmission of RBSDV. The differences of rice seedling, circulative period and the frozen time of plants can also affected efficiency in transmission of RBSDV.SBPH caused great harm on agricultural production. The research of SBPH requires a lot of SBPH. The current system of feeding planthopper is not perfect. At the same time there is lack of a mature platform to transmit RBSDV. Establish the platform then develop to be an excellent, standard platform to transmit RBSDV will be of essential to establish a resistance identification method of rice black-streaked dwarf disease. To improve the efficiency in feeding SBPH and establish a platform to transmit RBSDV, this paper designed a platform to feed SBPH efficiently and to transmit RBSDV. Though determination of growth state and living environment (light, temperature, humidity) of rice and SBPH, we found the practical effect of the platform is fine. As a platform to transmit RBSDV, the device significantly improved rice growth conditions, and can realize planting and transmiting RBSDV quantitatively. So it can become to be a resistance identification standard of RBSDV. As a platform to feed SBPH, the device has many advantages, such as feed of large-scale, efficiently and automatically, the kinds of crops fiting for plant and the kinds of insects fiting for plant are broad, low manufacturing costs, etc. we improved the system of feeding SBPH.