携带溶菌酶基因的高回交转育后代抗瘟性研究
Resistance of backcrossing lines with lysozyme gene to rice blast
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摘要: 进一步明确溶菌酶基因回交转育利用对于强优恢复系“明恢63”稻瘟病抗性改良的效果, 运用苗期人工接种和大田穗颈瘟鉴定相结合的方法, 研究了携带溶菌酶基因的高回交转育纯系对于稻瘟病的抗谱特性和穗颈瘟抗性。结果表明: 回交纯系对所应试的76个菌株中的6~8个感病, 稻瘟抗性频率为90%左右, 属高抗水平; 而轮回亲本“明恢63”对21个菌株感病, 抗性频率为72.37%, 属中抗水平。穗颈瘟调查分析表明, 回交转育纯系比轮回亲本发病率平均降低10%左右, 发病指数平均降低15%左右, 经T值检验二者在穗颈瘟抗性水平上差异达极显著水平, 回交转育纯系抗性评价为抗性(R)级, 轮回亲本为中感(MS)级。因此溶菌酶基 因的转育利用确能有效拓宽抗谱, 提高稻瘟病抗性水平, 这些回交转育品系在抗病育种上具有较高的应用 潜力。Abstract: It is of great significance to enhance blast resistance of parent elite hybrid rice by utilizing foreign genes with wild-spectrum resistance. In this paper, resistant spectrum and field-neck resistance of backcrossing lines with lysozyme gene were analyzed to enhance further understanding and improvement capacity of the gene. Artificial inoculation and field-neck resistance tests show that backcrossing lines have resistant frequencies of 90% and are susceptible to 6~8 strains in all of 76 strains of Magnaporthe grisea. Backcrossing lines are therefore ranked as a resistant (R) grade compared with recurrent parent “Minghui63” with 72.37% resistance frequency and susceptible to 21 fungus — ranked as middle resistant (MR) grade. T-test shows that backcrossing lines with lysozyme gene have a more notable field-neck resistance than the recurrent parent “Minghui63”. It achieves 10% reduction of disease incidence and 15% of disease index, making backcrossing lines as R grade and recurrent parent “Minghui63” as MS grade. From the above findings, it is concluded that foreign lysozyme gene broadens resistant spectrum thereby enhancing resistance against rice blast fungus. Transferring lines with lysozyme gene can therefore be available for breeding resistant rice variety.