Studies On The Methodology For Resistance Identification Of Rice Cultivar To Rice Black-Streaked Dwarf Disease And The Susceptible Growth Stages Of Rice To Rbsdv

Rice black-streaked dwarf disease caused by Rice black-streaked dwarf virus (RBSDV) is one of the important virus diseases of rice, which is transmitted by small brown planthopper (Aodelphax striatellus Fallen, SBPH). With the rapid increase of the amount of SBPH recently, the rice black-streaked dwarf disease is more and more serious in the eastern China. Applying resistant variety and controlling insect in proper period are the most effective measures to prevent and control this disease.Thus establishing the method of resistance identification of rice cultivar to rice black-streaked dwarf disease and making clear the susceptible growth stages of rice to RBSDV are needed firstly.The objective of this research was to study on the methodology for resistance identification of rice cultivar to rice black-streaked dwarf disease and the susceptible growth stages of rice to RBSDV. This study included three main parts. Firstly, we investigated the influences of virus latent time,inoculation intensity, inoculation time and inoculation stage of the seedlings on the resistance identification of rice cultivars to rice black-streaked dwarf disease. Secondly, we made a comparative study of 4 methods about acquiring RBSDV from frozen infected leaves. fresh infected leaves, fresh healthy plants and acquiring RBSDV form leaf juice of fresh infected leaves through parafilm M. Thirdly, we tested the Tetep and the susceptible variety Huajing No.6 at 2,4,6,8,10 leaf ages infected by RBSDV. The main results obtained are showed as follows:Firstly, the results revealed that 12-17days after the insects acquired virus,4-20 insects/seedling and 0.5-1.5 leaf age were the proper conditions for resistance identification. HuaidaoNo.5 R084 and Tetep were identified on the conditions whose result was almost consistent to the resistence identified in the field. Secondly, SBPH could not obtain virus form leaf juice of fresh infected leaves through parafilm M, and could obtain virus from frozen infected leaves. For the ability of obtain and transmit the virus of SBPH, it had significant difference comparing with fresh infected plants, while there were no significant difference comparing with fresh infected leaves.Thirdly, both the leaf age less than 8 for Tetep and the leaf age less than 10 for Huajing No.6 are the susceptible rice growth stages to this disease, so the seedling stage and the early field stage were susceptible. Moreover, the incidence of two varieties decreased with leaf ages.