Abstract: F₁, F₂, F₃ from six crosses (Ginga/Mokoto, Mokoto/Ginga,Homare-nishiki/Mokoto, Mokoto/Reimei, Ginga/Suiyuan-Sanbai-Li and Ginga/Jing-Yue 1)were used for studying field resistance to rice-blast (Pyricularia oryzae) in Dandong City, Liaoning Province from 1982 to 1985. Characters such as numbers of infected spots and susceptible lesions per 100 square centimeter leaf area, the expansion rate of susceptible lesion, diseased leaf area(DLA), percentage of neck blast and relative resistance index(RRI) were investigated. They all showed normal or bias continuous distribution in F₂ and F₃ populations, suggesting polygenic inheritance. The highest h_B² and h_N² estimated were susceptible lesion number (h_B²=79.5%) and percentage of neck blast (h_N²=65.3%) respectively. Parentoffspring correlation coefficients estimated from F₂ to F₃ were all over significant level. Therefore selection for field resistance to rice blast is available in early generations. It is suggested that it would onclick="SelectDisplayDiv('EnDivSummaryMoreSummary','EnDivSummaryMore');DisplaySpanDiv('EnDivSummaryHuanYuan')">...更多be convenient and efficient to use DLA as a criterion for selecting field resistance in early generations; susceptible lesion numbers and expansion rate should be evaluated simultaneously in higher generations if more accurate results are to be expected.

Key words: Rice blast, Field resistance, Inheritance, Selection

摘要： 1982～1985年在辽宁省丹东市前阳水稻试验站对用三个田间抗性亲本配成的六个组合(银河/蒙古稻、蒙古稻/银河、誉锦/蒙古稻、蒙古稻/黎明、银河/水原300粒和银河/京越1号)的F_1、F+2和F_3代的表现做了调查。试验结果表明,单位叶面积上的侵染点数和感病病斑数、病斑在单位时间内的扩展速度、发病叶面积百分率(DLA)以及穗颈瘟百分率在F_2和F_3的分布都为连续正态或偏态分布,变异位于双亲之间,很少有超亲现象,证明这种田间抗性为多基因控制的数量性状,广义遗传力(平均)和狭义遗传力(平均)分别以单位叶面积上的感病病斑数(h_B~2=79.5%)和穗颈瘟百分率(h_N~2=65.3%)最高。各性状的亲子相关都达显著水平。文中提出,育种中田间抗性的选择,低世代(2—4代)以DLA为指标,高世代(5代以后)以感病病斑数和病斑扩展速度为指标。对叶瘟和穗瘟抗性的选择应分别进行。

关键词: 稻瘟病, 田间抗性, 遗传, 选种