【作者】 U.A.Kapila Siri Udawela；

【导师】 高用明；

【作者基本信息】 中国农业科学院 ， 作物遗传育种， 2013， 博士

【摘要】 高温已成为严重影响水稻生长、产量和品质的一个主要因素。通过发掘水稻耐热基因/QTL,并结合分子设计育种手段来培育耐热水稻品种,被认为是提高水稻耐热性的有效途径之一。本研究以中国生产上已经大面积推广应用的两个优良籼稻恢复系蜀恢527和明恢86做为轮回亲本,以来自不同地理区域的13个品种为供体构建了13个BC2F2群体,在温室40℃的高温胁迫下以结实率为耐热指标以各自的轮回亲本为对照严格筛选到244个耐热高代回交导入系(13个BC2F5群体),开展了耐热及相关性状的鉴定和QTL定位,获得以下主要结果：1.在2011和2012年湖南正常条件下,以蜀恢527为背景的9个导入系群体平均表现与蜀恢527相近;在高温胁迫条件下,这9个群体中蜀恢527/明恢63热害指数和单株产量表现最好,其次为蜀恢527/孟关大麻谷和蜀恢527/紫恢100,蜀恢527/辐恢838表现最差,其他群体的表现不尽一致。在湖南正常条件下,以明恢86为背景的4个导入系群体的平均表现和明恢86的相近;高温胁迫条件下,平均两年的抗旱指数和单株产量为耐热评价指标,全部4个明恢86背景的群体耐热性都较轮回亲本明恢86有明显改良。共计获得了10个优良耐热导入系,来自蜀恢527和明恢86背景的各有5个。在浙江杭州的正常和高温胁迫条件下,共获得6个优良株系,蜀恢527/孟关大麻谷和蜀恢527/BG902群体各有3个株系。而且,在2012年来自蜀恢527/孟关大麻谷群体的3个株系在正常和高温胁迫条件下都比耐热对照品种N22表现出更高的实粒数和单株产量。2.蜀恢527/孟关大麻谷和蜀恢527/BG902群体,共检测到与9个性状有关的58个QTL,其中5个控制抽穗期、1个控制株高、3个控制有效穗数、7个控制每穗实粒数、9个控制每穗颖花数、11个控制结实率、5个控制千粒重、5个控制单株产量和12个控制耐热指数。其中13个QTL在两地点被重复检测到。明恢86为轮回亲本与江西丝苗、IR65600-27-1-2-2、旱恢10和Bala为供体的导入系群体共检测到214个QTL,与抽穗期有关的位点有22个、与株高有关的位点18个、与有效穗数有关的位点32个、与每穗实粒数有关的位点23个、与每穗总粒数有关的位点28个、与结实率有关的位点24个、与单株产量有关的位点24个、与耐热指数有关的位点13个。本研究的结果表明,回交导入结合目标性状选择的策略进行水稻耐热性的改良和耐热基因/QTL的发掘和定位是有效的。更多还原

【Abstract】 High temperature is a major disastrous factor on crop growth and reduction of yield and quality of rice. It is prime requirement to exploit and detect QTL controlling heat tolerance, combining with molecular designed breeding to develop heat tolerant cultivars for the warmer world. In our study,13BC2F2bulk harvested seeds were derived from two widely used indica elite restorers (Shuhui527and Minghui86) in China as the recurrent parents, and13varieties from different geographical regions as the donors. BC2F2Thirteen populations were screened for heat stress under green house condition with～40℃using spikelet fertility as selection criteria with RP. All the progenies were reevaluated for yield and its related phenotypic traits under heat stress condition (plastic shed) and normal condition in Hunan provinces in2011and2012while two populations of Shuhui527background were evaluated under both conditions for two years in Zhejiang province, Hangzhou. Two populations with Shuhui527background and four populations with Minghui86background were genotyped to identify quantitative trait loci (QTL) underling heat tolerance in rice. The main results were as follow:1. Phenotypic evaluation in2011and2012in Hunan for nine ILs populations of Shuhui527under normal condition have shown that more or less the same performance with the recurrent parent (Shuhui527). Considering average heat stress index and grain yield under stress condition for two years, the best population was shuhui527/Minghui63out of nine populations, followed by Shuhui527/MGDMG and Shuhui527/Zihui100populations. Population Shuhui527/Fuhui838showed the lowest performance, while the remaining five populations had more or less same performances compared to Shuhui527. Phenotypic evaluation of four populations derived with Minghui86background in Hunan2011and2012under normal condition have shown not much different with Minghui86for measured data. However, considering average heat stress index and grain yield under stress condition for two years, all the four populations have shown improvement compared to RP (Minghui86). A total of ten promising heat tolerant ILs (five ILs from Shuhui527background and other five ILs from Minghui86background) were identified based on two rounds grain yield phenotypic evaluation. In addition to that, three promising lines from each population Shuhui527/MGDMG and Shuhui527/Bg90-2were identified under normal and heat stress conditions in Zhejiang province, Hangzhou. Interestingly, all the3lines from Shuhui527/MGDMG population have shown higher filled grain rate and grain yield under both normal and stress conditions compared to N22heat check in2012.2. A total of58QTL were identified for nine phenotypic traits in Shuhui527/MGDMG and Shuhui527/BG902populations under normal and heat stress conditions in Hunan and Zhejiang provinces in2011and2012, including five for heading data, one for plant height, three for panicle number, seven for filled grain number, nine for spikelet number per panicle, eleven for filled grain rate, five for thousand grain weight, five for grain yield and twelve for heat stress index. Thirteen QTL were detected at both Hunan and Zhejiang environments at least under one condition or both. Furthermore, a total of214QTL were identified in Minghui86populations with Jiangxisimiao, IR65600-27-1-2-2, HanhuilO and Bala as donors in Hunan, including22QTL for heading data,18QTL for plant height,32QTL for panicle number,23QTL for filled grain number,28QTL for spikelet number per panicle,24QTL for filled grain rate,30QTL for thousand grain weight,24QTL for grain yield and13QTL for heat stress index.In a word, the results of this study showed that the strategy of backcrossing combing with imposing critical selection on the target trait for improving heat tolerance and identifying favorable heat tolerance genes/QTL in rice is effective.更多还原