Evaluation of Rice Germplasm for Resistance to the Small Brown Planthopper and Analysis on Resistance Mechanism

One hundred and thirty-eight rice accessions were evaluated for resistance to the small brown planthopper(SBPH)(Laodelphax striatellus Fallen)by seedbox screening test with modification.Twenty-five rice accessions with different levels of resistance to SBPH were detected,accounting for 18.1% of the total accessions,which included two highly resistant,nine resistant and 14 moderately resistant varieties.Compared with indica rice,japonica rice was more susceptible to SBPH.Antixenosis test,antibiosis test and correlation analysis were performed to elucidate the resistance mechanism.The highly resistant varieties such as Rathu Heenati(RHT),Mudgo and Kasalath and resistant variety IR36 expressed strong antixenosis and antibiosis against SBPH,indicating the close relationship between resistance level and these two resistance mechanisms in the four rice varieties.Antibiosis was the dominant resistance pattern in the resistant varieties Daorenqiao and Yangmaogu due to their high antibiosis.Dular,ASD7 and Milyang 23 had relatively strong antixenosis and antibiosis,indicating the two resistance mechanisms were significant in these three varieties.The resistant variety DV85 expressed relatively high level of antixenosis but low antibiosis,while Zhaiyeqing 8 and Guiyigu conferred only moderate antibiosis and antixenosis to SBPH,suggesting tolerance in these three varieties.Antibiosis and antixenosis governed the resistance to SBPH in the moderately resistant variety 9311.Antixenosis was the main resistance type in V20A.Tolerance was considered to be an important resistance mechanism in Minghui 63 and Yangjing 9538 due to their poor antibiosis and antixenosis resistance.The above accessions with strong antibiosis or antixenosis were the ideal materials for resistance breeding.