【作者】 石英尧；

【导师】 黎志康； 高用明；

【作者基本信息】 安徽农业大学 ， 作物遗传育种， 2013， 博士

【摘要】 本研究选用生产上大面积推广应用的籼型水稻恢复系明恢86和蜀恢527为轮回亲本，以桂99、R2004、lemont、云恢72四个品种为供体亲本，构建了8个BC2F4回交导入系群体，经过田间目测对产量性状和茎秆形态学性状进行鉴定、并结合测力计测定茎秆抗折力进行产量性状和抗倒伏性状的双重筛选，构建了8个高产、抗倒伏能力强的选择回交导入系BC2F4群体。于2008年和2009年在合肥进行产量性状和抗倒伏相关性状的表型鉴定，在2009年在中国农科院作物科学研究所重大工程楼进行基因型鉴定，进而对实粒数、总粒数、结实率、千粒重、理论产量等5个产量性状和茎秆粗、壁厚、基部第二节间抗折力、基部第三节间抗折力、倒伏指数等5个抗倒伏性状进行了表型和基因型分析。分析内容包括：产量和抗倒伏能力的选择效果分析、产量和抗倒伏性状的相关性分析、产量性状和抗倒伏性状的QTL定位和效应分析、产量性状与抗倒伏性状的遗传重叠分析。研究结果对于高产、抗倒伏水稻育种中有利基因/QTL的利用、后代材料的直接和间接利用、高产和抗倒伏性状的同步协同改良有重要参考价值。主要研究结果如下：1、高产、抗倒伏选择回交导入的选择效果以蜀恢527和明恢86为轮回亲本的8个回交导入系群体在BC2F4代进行产量和抗倒伏相关性状的鉴定选择，入选的190个选择回交导入系于2008年和2009年进行了表型鉴定。两年分别有150个、154个株系的单株产量高于轮回亲本，占入选株系数的78.9%和81.1%，在两年中均比对照增产的株系有143个，占75.3%。两年均稳定增产达到10%以上的株系有101株，占53.2%，比例较高，可见入选优良株系以基因型决定为主，选择效果良好。产量选择的效果在不同轮回亲本的组合间表现有一定差异，以蜀恢527为轮回亲本的四个组合产量选择效果相对较好。2008年和2009年中分别有128个、131个株系的倒伏指数低于轮回亲本，分别占67.4%和68.9%。两年中均比轮回亲本倒伏指数小的株系数有108个，占56.8%。两年倒伏指数均比轮回亲本降低5%以上的株系有63株，占33.2%。两年中株系倒伏指数表现趋势总体上一致，以基因型决定为主，选择效果良好。不同组合的选择效果略有差异，其中527－99、527－72入选株系倒伏指数低于轮回亲本的比率在两年中均较高，表现好且稳定。两年中比轮回亲本增产、倒伏指数降低的株系数有82个，占43.2%。从结果看把产量性状和抗倒伏性状同步进行选择改良是可行的，高产和抗倒伏能够得到协同改良。采用选择回交导入系对产量和抗倒伏能力结合起来同步进行改良方法可行、效果良好。从选择导入系的表现看，桂99作为供体亲本对改良轮回亲本的产量性状有很好效果，R2004作为供体对改良轮回亲本的抗倒伏能力的效果很好，在实践育种中可加强利用。从两年在产量性状和抗倒伏两方面稳定表现优良的株系产量因子看，要做到既高产又抗倒，需要一个理想的穗粒结构，一般总粒数在200粒左右，实粒数在160－180粒为宜。2、产量和抗倒伏相关性状的相关性高产育种重点要从提高分蘖力和结实率、确保一定的实粒数和保持较高的千粒重几个方面着手，不可以追求长穗和特大穗。保持足够穗数和较大穗的基础上主攻结实率是关键，特别是把高产、抗倒伏两方面作为育种目标时，应从有效穗、实粒数、结实率上下功夫，保持较高的粒重，不能追求大穗、长穗。提高水稻的抗倒伏能力，首先要从增加茎秆粗和壁厚、增加节数入手，改良水稻的秆型指数，进而提高抗倒伏能力。在选育中矮秆、高产、抗倒伏品种时，对品系抗倒伏能力的评价可以直观地把节数、茎秆粗和壁厚作为重要指标，结合测定茎秆抗折力或抗推力，对水稻的抗倒伏能力进行科学准确的评价。3、主效QTL及其利用定位到了多个P值小于0.01、贡献率在30%以上、加性效应较大、且在两年都稳定表达的主效QTL位点，这些位点可以作为产量性状和抗倒伏性状改良的重点。如控制实粒数的qGN10.1、qGN7.1、qGN1.2、qGN1.3、qGN11.4、qGN2.1，控制总粒数的qSN2.1、qSN1.3、qSN1.4、qSN1.5、qSN2.4，控制结实率的qSF10.1、qSF5.1、qSF1.1、qSF3.4、qSF4.1、qSF5.3、qSF6.2、qSF1.3、qSF1.4，控制千粒重的qGW2.1、qGW7.1、qGW12.1、qGW1.5、qGW1.6、qGW6.4、qGW7.5，控制理论产量的qGY3.1，控制茎秆粗的qSD2.2、qSD1.1、qSD1.6、qSD1.3、qSD1.4、qSD2.8、qSD1.9，控制壁厚的qCT2.2、qCT2.1、qCT7.3、qCT1.3、qCT1.4，控制基部第二节间抗折力的qCS7.1、qCS9.1、qCS1.3、qCS1.4、qCS1.5，控制基部第三节间抗折力的qCSⅢ7.1、qCSⅢ9.1、qCSⅢ12.4、qCSⅢ1.2、qCSⅢ1.3、qCSⅢ1.4、qCSⅢ2.1，控制倒伏指数的qLI1.2、qLI7.2。有的QTL中供体基因的导入可以使某个产量指标或抗倒伏指标得到大幅度改良，但导致另外主要产量因子的下降，所以有利基因/QTL的利用要考虑到主要性状之间的相关性。4、产量和抗倒伏相关性状的遗传重叠在群体内产量性状间、抗倒伏性状间、产量和抗倒伏性状间、相同背景不同供体间都有较多的遗传重叠，这些遗传重叠为产量性状和抗倒伏性状的同步改良创造了条件。如在527－72群体中检测到在第1染色体上的三个相邻的主效位点qGN1.2（qSN1.3、qCS1.3、qCSIII1.2）、qGN1.3（qSN1.4、qCS1.4、qCSIII1.3）、qGN1.4（qSN1.5、qCS1.5、qCSIII1.4），对实粒数、总粒数、基部第二和第三节间抗折力都表现为较大的负向加性效应，增效作用来自于供体云恢72，在这几个位点导入供体亲本基因能较好地提高实粒数、总粒数和第二、第三节间抗折力，可利用分子标记辅助选择在这些位点上表现为供体基因型的个体，对蜀恢527从高产、抗倒伏两大目标进行改良和后代选择具有重要意义。有的一因多效QTL对不同性状的同步改良不利，要因具体亲本材料和育种目标而灵活应用，并加强选择，使有利的效应得到充分发挥，在一定程度上避免负面作用。在相同遗传背景、不同供本材料中，相同位点的作用效果也会有差异。在育种中要对亲本充分的评价和了解，弄清有利的基因/QTL表达特点及其与环境的互作，进而有效的利用。更多还原

【Abstract】 In this study, Shuhui527and Minghui86, which were two widely used eliteindica restorers in China, were used as the recurrent parents, Gui99, R2004, lemont andYunhui72as donors for developing eight BC2F2backcrossing introgression populations.These populations were imposed critical screening for yield and lodging resistance (LR)traits, through field estimation of yield traits and morphology traits of culms combiningwith the determination of culm bending force using dynamometer, from which eight BC2F4selected backcrossing introgression populations with high yield and lodging resistancewere developed. The progeny of the BC2F4backcrossing populations and their parentswere tested for yield and LR traits in2008and2009in Hefei. The identification ofgenotyping was conducted in the National Key Facility for Crop Gene Resources andGenetic Improvement/Institute of Crop Science in Chinese Academy of AgriculturalSciences (CAAS) in2009. Five yield traits (filled-grain number per panicle, spikelets perpanicle, spikelet fertility, thousand grain weight and theoretical yield) and five LR traits(stem diameter, wall thickness, flexural strength of the second internode, flexural strengthof the third internode and lodging index) were used for phenotypic and genotypic analysis.The analysis included the selection effect analysis of yield and LR, correlation analysis ofyield and LR traits, QTL mapping and effect analysis of yield traits and LR traits, thegenetic overlap analysis of yield and LR traits. The results in this study provide importantinformation for the application of favourable gene or QTLs in high yield and LR breeding,the direct and indirect use of progenies, and the simultaneous improvement of yield andLR traits. The main results are as follows:1. The effectiveness of the selection for yield and lodging resistance traitsThe eight BC2F4backcrossing populations in the genetic background of Shuhui527andMinghui86were imposed critical selections for yield and LR traits, from which a total of190introgression lines (ILs) were selected. Progeny testing allowed the identification of150(78.9%) and154(81.1%) lines which showed better yield performances than therecurrent parents. Of which,140lines had higher yield than the recurrent parents in two years, accounted for75.3%of the ILs. Furthermore,101lines with10%stably increasedyield in two years accounted for a lager portion (53.2%), the selected superior lines weremainly determined by genotypes, thus demonstrated the effectiveness of the selection.There was a certain difference in the effectiveness of the yield selection between thepopulations of different recurrent parents, the four populations with Shuhui527as therecurrent parent had better performances.In2008and2009, there were128and131lines which had lower lodging index thanthe recurrent parent, account for67.4%and68.9%respectively. Of which,108lines hadlower lodging index than the recurrent parents in two years, accounted for56.8%of the ILs.Furthermore,63lines with5%decreased lodging index in two years accounted for33.2%.In general, the ILs showed the consistent trend of the lodging index, they were mainlydetermined by genotypes, thus demonstrated the effectiveness of the selection. There weredifferences in the effectiveness of the selection among different populations. There was ahigh percentage of ILs in527-99and527-72populations which had lower lodging index intwo years with good and stable performances.Compared with the recurrent parents,82ILs had higher yield and low lodging index,accounted for43.2%. These findings indicated that it is feasible to make improvement ofyield and LR traits simultaneously, thus achieve high yield and LR together. Therefore, ourresults revealed an efficient breeding strategy using selected backcross introgression linesfor improving yield and LR in rice.The donor parent Gui99play an important role in the improvement for yield traits ofthe recurrent parents while the donor parent R2004contributed more in the improvementof LR traits, they could be used as materials in the practice breeding.Take the yield components of superior lines with stable performances in both yield andLR into consideration, if high yield and LR is to achieve, an ideal grain structure is needed,the general spikelets per panicle is about200, filled-grain number with160-180grains isadvisable.2. Correlation between yield and lodging resistance related traitsThe key points in high yield breeding could be conducted to improve the tilleringability and spikelet fertility, to ensure certain filled-grain number per panicle, maintaininghigh thousand grain weight, rather than pursuit the long and huge panicle. On the basis ofenough panicle number and large panicle, the high or low spikelet fertility is the mostimportant point. Panicle number, filled-grain number per panicle, and spikelet fertility should be considered, especially when the high yield and lodging resistance were set as thebreeding goal.In order to improve the lodging resistance of rice, stem diameter, wall thickness andthe number of internodes should be increased, the culm type should be improved, thusimprove the lodging resistance.During the breeding process of developing dwarf, high yield and lodging resistancevarieties, the number of internodes, stem diameter and wall thickness can be used as animportant index. Furthermore, the determination of stem bending force or thrust is alsoconsidered to evaluate the lodging resistance of rice.3. The main effect QTL and its applicationThe results of QTL mapping showed that many QTLs were identified at the significantlevel P<0.01. These identified QTLs were explained over30%of the phenotypic variationswith large additive effect and expressed stably in two years. It is indicated that these lociare important for the improvement of yield and lodging resistance traits, such as qGN10.1,qGN7.1, qGN1.2, qGN1.3, qGN11.4and qGN2.1controlling the filled-grain number,qSN2.1, qSN1.3, qSN1.4, qSN1.5and qSN2.4controlling spikelets per panicle, qSF10.1,qSF5.1, qSF1.1, qSF3.4, qSF4.1, qSF5.3, qSF6.2, qSF1.3and qSF1.4controlling spikeletfertility, qGW2.1, qGW7.1, qGW12.1, qGW1.5, qGW1.6, qGW6.4and qGW7.5controllingthousand grain weight, qGY3.1controlling grain yield, qSD2.2, qSD1.1, qSD1.6, qSD1.3,qSD1.4, qSD2.8and qSD1.9controlling stem diameter, qCT2.2, qCT2.1, qCT7.3, qCT1.3and qCT1.4controlling wall thickness, qCS7.1, qCS9.1, qCS1.3, qCS1.4and qCS1.5controlling flexural strength of the second internode, qCS Ⅲ7.1,qCS Ⅲ9.1,qCS Ⅲ12.4,qCS Ⅲ1.2, qCS Ⅲ1.3, qCS Ⅲ1.4and qCS Ⅲ2.1controlling flexural strength of thethird internode, qLI1.2and qLI7.2controlling lodging index. The introgressions of thedonor at some loci have greatly improved some index of yield and lodging resistance, butled to a decline in other major yield components. Therefore, the correlations among themain traits should be taken into account when some favorable genes/QTLs would beintrogressed.4. The genetic overlap of yield and lodging resistance traitsThere were genetic overlaps among yield traits within the same population, betweenyield and LR traits, among the donors in the same genetic background. These geneticoverlaps provided useful information for the simultaneous improvement of yield and lodging resistance traits. For example, three adjacent main effect QTL, qGN1.2(qSN1.3qCS1.3qCSIII1.2), qGN1.3(qSN1.4qCS1.4qCSIII1.3) and qGN1.4(qSN1.5qCS1.5qCSIII1.4) which were detected on the chromosome1in the527-72population, hadnegative additive effect on filled-grain number, spikelets per panicle, flexural strength ofthe second internode and flexural strength of the third internode. The favorable alleles werefrom Yunhui72, which contributed to the increased filled-grain number, spikelets perpanicle, flexural strength of the second internode and flexural strength of the thirdinternode. These QTLs could be applied in the marker-assisted selection (MAS), thus playan important role in the improvement of high yield and LR and progeny selection.To a certain extent, several pleiotropic QTLs were unfavorable for the improvementof different traits simultaneously, so the strategy should be flexible according to differentmaterials and breeding goals and critical selection is needed, thus make good advantage ofthe effects of these QTLs and avoid negative effects. In addition, the expression of thesame QTL is different in different donors under the same genetic background. During thebreeding process, adequate evaluation of the parent is needed. Then, we should get tounderstand the characteristics of the expressions of those favorable genes/QTLs and theirinteractions with the environment in order to make good advantage of them.更多还原