含Bph3抗褐飞虱基因的水稻品种自20世纪80年代在东南亚推广后,迄今仍对褐飞虱有较好的抗性,受到我国抗褐飞虱育种专家的重视。在IR56水稻(含Bph3基因)上连续40多代胁迫饲养获得褐飞虱IR56寄主种群,从褐飞虱的生长、发育、繁殖以及水稻品种的抗感反应(SSST法测定)两方面对该种群的致害性进行了研究。结果表明:1)在抗性水稻IR56上,褐飞虱IR56种群的羽化率、初羽化成虫体质量、成虫寿命、产卵量、蜜露排泄量、体质量增量等均较褐飞虱TN1种群显著增加,若虫历期则显著缩短;与感虫水稻TN1上的IR56种群或TN1种群相比,除成虫寿命、蜜露排泄量和体质量增量显著下降外,羽化率、产卵量、卵孵化率无显著差异,初羽化成虫体质量、若虫历期尽管差异显著但数值上较接近(其差值不及IR56水稻上IR56种群与TN1种群差值的1/2)。2)水稻品种苗期抗性反应显示IR56水稻对褐飞虱IR56种群的抗性级别为7级,明显弱于对褐飞虱TN1种群的3级,但略强于TN1水稻对褐飞虱IR56种群或TN1种群的9级。显然,与褐飞虱TN1种群相比,褐飞虱IR56种群对抗性水稻IR56有较强的致害能力,与IR56种群或TN1种群对TN1水稻的强致害水平尽管有一定的差距,但多数指标较为接近。含Bph3基因的水稻品种RathuHeenati对IR56种群抗性为1级,推测可能与该水稻品种存在Bph3以外的其他抗虫基因有关。

Rice varieties with the planthopper resistance gene Bph3were initially released and promoted in the Southeast Asia in the early 1980s. These varieties are still resistant to the brown planthopper [BPH, Nilaparvatalugens (Stål)], which has attracted much attention of rice breeders in China. A local BPH population that was forced to feed on IR56 with Bph3 gene for over 40 generations (IR56p) was used to study the virulence characteristics from perspectives of insects (development and reproduction) and rice variety reaction (SSST test). The results were as follows: 1) IR56p reared on resistant rice IR56 (IR56p-IR56) showed significantly increased emergence rate (ER), newly emerged adult body weight (BW), adult longevity (AL), number of eggs laid (NE), honeydew excretion (HE), and adult weight gain (WG), as well as markedly decreased nymphal duration (ND), compared to TN1 population (TN1p, a normal population reared on a susceptible rice variety TN1) on rice IR56 (TN1p-IR56). In contrast, IR56p-IR56 showed similar ER, NE and egg hatchability(EB), compared to TN1p or IR56p reared on rice TN1 (TN1p-TN1 or IR56p-TN1), despite significantly lower ND, AL, HE, WG and longer ND. The difference in BW and ND between IR56p-IR56 and TN1p-TN1 (or IR56p-TN1) was less than half of that between IR56p-IR56 and TN1p-IR56. 2) SSST test showed that the resistance of rice IR56 to IR56p was Grade 7, higher than Grade 3 of IR56 to TN1p. The resistance of TN1 to IR56p and TN1p was Grade 9 (total loss). It is concluded that the virulence of IR56p to IR56 is much higher than that of TN1p to IR56. Although the virulence of IR56p to IR56 was lower than that of IR56p or TN1p to TN1, most evaluations were similar among the three groups. In addition,the resistance of another Bph3-containing variety RathuHeenati to IR56p was Grade 1 (high resistance). Such an unexpected result implies that other BPH resistance genes contributes to the resistance of RathuHeenati to IR56p.