转基因抗虫性水稻恢复系选育及特性分析

Breeding and Characteristic Analysis of a Rice Restorer Line with Bt-Resistance Gene

将优质抗稻瘟病水稻恢复系成恢177与转基因水稻Bt明恢63杂交并回交1次,采用PCR分析、试纸条检测、室内和田间人工接虫鉴定抗虫性,并结合系谱法选择农艺性状,病圃接种鉴定稻瘟病抗性,育成具转基因抗虫性的水稻新恢复系Bt5198。采用离体茎秆法接种二化螟卵块,新恢复系Bt5198和Bt明恢63的幼虫死亡率均为100%。在田间人工接虫条件下,该恢复系对二化螟和三化螟均表现高抗,与4个不育系配制的杂种F1仍保持良好的抗虫性,且杂种优势明显。两年稻瘟病抗性鉴定结果表明,新恢复系Bt5198的叶瘟和颈瘟抗性水平与成恢177相当,明显优于Bt明恢63。Bt5198的种子发芽率和花粉量与成恢177相当,Bt基因导入水稻恢复系不会对种子生活力和制种产量造成显著影响。在无选择标记基因的转基因后代中,结合利用试纸条检测和室内、田间人工接虫鉴定是筛选Bt基因抗虫性的有效方法。

Bt5198, a new rice restorer line with Bt-resistance gene, was developed from the cross and backcross of the elite restorer line Chenghui 177 with rice blast resistance and Bt Minghui 63, a Bt transgenic restorer line. The inbred lines were evaluated by using PCR amplification, test paper evaluation, insect resistance evaluation in greenhouse and paddy fields, nursery evaluation of rice blast resistance and pedigree selection of agronomic traits. Larval mortalities on Bt5198 and Bt Minghui 63 were both 100% when the eggs of the striped stemborer （SSB） were inoculated on rice culms in laboratory, and Bt5198 was highly resistant against SSB and the yellow stemborers （YSB） under field conditions. The F1 hybrids derived from Bt5198 and four cytoplasmic male sterile lines were also highly resistant against SSB and YSB, and had a significant heterosis. Two-year evaluation of rice blast resistance confirmed that the resistance levels to leaf blast and neck blast in Bt5198 were similar to those in Chenghui 177 and significantly higher than those in Bt Minghui 63. The ability of seed germination and pollen yield of Bt5198 were similar with Chenghui 177, suggesting that the introduction of Bt gene into the new restorer line had no significant influence on seed vigor and seed production yield. To identify the Bt gene, it is effective to combine test paper examination with the evaluation of insect-resistance in laboratory and under field conditions.