摘要：

为了改良桃农1B和桃农1A的苗瘟抗性,以携带广谱持久抗稻瘟病基因Pigm的中国地方水稻品种谷梅4号为供体亲本,先后以三系保持系桃农1B及其不育系桃农1A为受体亲本,利用与Pigm紧密连锁共显性DNA标记T9E3开展辅助选择育种。T9E3在桃农1B或桃农1A基因组中的PCR扩增条带约为2 000 bp,而对谷梅4号基因组的扩增产物大小为926 bp,多态性稳定;采用来自国内外不同稻区的32份稻瘟菌菌株室内接种苗瘟,桃农1B和桃农1A抗性频率均为9.38%,谷梅4号与改良系抗性频率均为90.63%;田间天然病圃鉴定桃农1B和桃农1A苗瘟8级,而改良系和供体亲本谷梅4号苗瘟均为0级。通过T9E3辅助选择、田间病圃筛选和室内接种鉴定,初步获得了3份高抗稻瘟病的改良不育系(桃农1A-Pigm-1─桃农1A-Pigm-3)及其保持系(桃农1B-Pigm-1─桃农1B-Pigm-3),进一步通过不育特性、农艺性状与产量结构调查分析,从中遴选出1个高抗稻瘟病、不育性稳定、包颈率低、农艺产量性状优良的优异不育系桃农1A-Pigm-2及其配套保持系桃农1B-Pigm-2。桃农1A-Pigm-2不育度和不育株率均为100%,典败花粉约占60%、圆败花粉约占40%,柱头外露率高达71.1%,包颈粒率仅为33.6%;桃农1B-Pigm-2播始历期为69 d,株高76.2 cm,主穗穗长28.1 cm,单株有效穗数15.8穗,单穗总颖花数115.3个,千粒质量27.7 g。实现了桃农1A和桃农1B苗瘟抗性及其他性状的综合改良,为三系杂交水稻育种应用创制了新的亲本材料。

关键词: 水稻, 稻瘟病抗性改良, 分子标记辅助选择, Pigm, 桃农1A, 桃农1B

Abstract:

To improve seedling blast resistance of rice cytoplasmic male sterile(CMS)line Taonong1A and its maintainer Taonong1B,the Chinese local rice variety Gumei 4 was used as the donor parent harboring the broad-spectrum and durable blast resistance gene Pigm,and the Pigm-tightly-linked codominant marker T9E3 was developed and employed in marker-assisted selection(MAS)breeding practice.T9E3 showed clear and stable polymorphism between the donor and acceptor parents,amplifying a 926 bp DNA band from Gumei 4 genome,while the PCR product from either genome of Taonong1B or Taonong1A was about 2 000 bp.Greenhouse inoculation assay was performed using thirty-two Magnaporthe oryzae isolates collected from different rice areas,Gumei 4 and the improved rice lines showed much higher resistance frequency(90.63%)than that of two acceptor parents Taonong1B and Taonong1A(9.38%).Accordingly,Gumei 4 and the improved rice lines showed high-level seedling blast resistance(0 grade)but highly susceptible(8 grade)for two acceptor parents in natural nursery.Three blast resistant CMS pure lines(Taonong1A-Pigm-1—Taonong1A-Pigm-3)and the corresponding resistant maintainers(Taonong1B-Pigm-1—Taonong1B-Pigm-3)were preliminarily bred through MAS breeding,and one pair of them,Taonong1A-Pigm-2/Taonong1B-Pigm-2,was screened for potential application duo to the high-level blast resistance and elite sterility,agronomic and yield traits.Taonong1A-Pigm-2 showed complete male sterility with nearly 60% typical abortive pollens and 40% round abortive pollens,higher stigma exsertion rate(71.1%)and lower enclosed spikelet rate(33.6%),Taonong1B-Pigm-2 exhibited excellent agronomic and yield trait indexes,such as moderate sowing-heading duration(69 days),plant height(76.2 cm),main panicle length(28.1 cm),panicles per plant(15.8),spikelets per panicle(115.3)and 1000-grain weight(27.7 g)。New parent materials were created for the application of cytoplasmic male sterile(CMS)line hybrid rice breeding,and the comprehensive improvement of seedling blast resistance and characters of Taonong1A and Taonong1B were realized.

Key words: Rice, Rice blast resistance improvement, Molecular marker-assisted selection, Pigm, Taonong1A, Taonong 1B