Evaluation of indica rice A232 and its derived RILs on resistanceEvaluation of indica rice A232 and its derived RILs on resistance

Author of the article:XIE Rong1** LI Yong-Hong1 LIU Cheng-Yuan1 XIANG Jian-Yu1 PENG Yun-Liang2***

Author's Workplace：1. Rice and Sorghum Institute, Sichuan Academy of Agricultural sciences/ Key Laboratory of Rice Biology, Genetics and Breeding in Southwest, Ministry of Agriculture, Deyang 618000, China; 2. Institute of Plant Protection, Sichuan Academy of Agricultural sciences/ Key Laboratory of Integrated Pest Management on Crops in Southwest, Ministry of Agriculture, Chengdu 610066, China

Key Words：rice, recombinant inbred lines (RILs), Tryporyza incertulas (Walker), spawning tropism

Abstract： [Objectives]  To identify genotypes of rice resistant to Tryporyza incertulas (Walker) for the selective breeding of more resistant strains. [Methods]  Female T. incertulas moths were attracted by light traps to 5 control varieties of rice and 10 RILs derived from Gang 46B ×A232 under natural conditions on Hainan Island. Oviposition on rice plants was statistically analyzed among different the different rice genotypes. [Results]  Egg masses were aggregated on rice plants. The aggregation average (lambda) value was < 2 in the three control varieties (i.e. A232, TTP and F77) and 4 RILs (i.e. RILsC22-230, C22-174, C22-113 and C22-133), suggesting that these lines are somewhat repellent to ovipositing female moths. Egg mass abundance, as assessed by both leaf and tiller indices, were significantly different among rice genotypes (P<0.05 and 0.01, respectively).  Leaf and tiller egg mass indices for Gangyou 188 were 6.1 times and 5.7 higher, respectively, than in A232. Leaf and tiller egg mass indices in C22-99  were 2.7 times and 3.3 higher, respectively, than in C22-113. Our data revealed that the A232, TTP and C22-113 rice strains were relatively resistant to female moth oviposition and larval feeding. We subsequently divided the 15 rice lines into two types on the basis of their similarity to the resistant parent A232, or the susceptible parent, Gang 46B. [Conclusion]  Resistance to female moth oviposition was significantly different among different rice genotypes tested. It is necessary to consider resistance to both larval damage and female moth oviposition to evaluate the overall resistance of rice varieties to T. incertulas.