增加种植密度是玉米等主要农作物产量提升的关键措施之一，但密植易造成倒伏、空秆、穗粒数下降等系列问题。优良的株型是实现合理密植、提高产量的前提，较高的个体产量水平是实现群体高产的基础。本研究针对制约玉米密植高产的限制因素，利用玉米关联群体、MAGIC群体和重组自交系等群体，采用连锁分析、全基因组关联分析以及综合应用数量遗传学、分子遗传学、分子生物学、蛋白质组学和生物信息学等多学科理论和方法，克隆了7个调控玉米株型的新基因，建立了玉米株型基因调控新网络，为玉米理想株型分子育种提供重要基因资源；克隆了4个调控玉米产量因子的新基因，为提升玉米籽粒产量提供了分子途径；创制了多份携带优良等位基因的高产新材料，为玉米高产育种提供了育种材料。Increasing plating density is one of the key strategies to improve the yields of maize and other crops.However,planting under high density usually causes many problems,such as lodging,empty stalk and decreased grain number.Upright plant architecture is the premise of achieving reasonable dense planting,and higher grain yield per plant is the basis of obtaining high population yields.To dissect the genetic basis of dense plating and high yields,we comprehensively employed linkage mapping and GWAS,as well as methods that integrate quantitative genetics,molecular genetics,proteomics and bioinformatics After five years of efforts,we totally cloned seven genes regulating maize plant architecture and revealed the underlying molecular regulatory network,which provides important target genes for maize ideal plant architecture breeding.In addition,we cloned four new genes controlling maize yield components,providing molecular pathways that improves grain yield.Using the favorable alleles identified from natural populations,we created many novel improved lines,which provides important materials for high yields breeding.

作物株型是一个由植株分蘖角、叶夹角、分蘖数目、穗型和株高等性状共同决定的综合农艺性状，它决定作物群体产量。高大披散的株型不利于作物密植生产，还容易滋生病虫害。分蘖数过多会导致茎杆细小，不抗倒伏，严重影响稳产性。加强高产株型研究有利于培育高产和稳产作物新品种。本课题利用GWAS揭示了水稻叶夹角和分蘖角具有不同的遗传基础,bHLH转录因子第16亚家族成员具有保守的叶夹角调控功能。第一次阐释了HD-ZIP转录因子通过影响生长素和独脚金内酯的合成代谢，调控水稻分蘖角度和分蘖数目的作用机制。明确了叶夹角主要由叶枕起始和发育过程决定，揭示了OsLG2/2L和OsLG1决定叶枕的器官发生，从而影响叶夹角的大小。克隆了水稻高产基因qGY3,它通过调控细胞分裂素合成来促进穗二次枝梗增加，从而显著增产。分离了顶部小穗退化的PAA1基因，该基因通过影响穗顶部苹果酸运输，引起paa1顶部小穗细胞死亡。挖掘出水稻株型发育的重要基因IDS1并解析了该重要基因调控株型的分子机制。克隆了水稻高产基因RHY2,发现该基因通过调控IPA1的表达量进而调控水稻株型的形成。在小麦6B染色体定位小麦株高主效QTL qPh-6B,确定候选基因TraesKN6B-PH。另外，我们利用连续回交，把qGY3和RHY2导入3份骨干恢复系和2个重要品种，获得了显著增产的新材料。本课题的研究不仅丰富了株型的调控网络，而且鉴定的分蘖角、叶夹角、叶枕发育、穗型及株高优良等位基因是培育作物理想株型品种的优异基因资源。Crop plant architecture is a comprehensive trait determined by tiller angle,flag leaf angle,tiller number,panicle architecture and plant height.Plant architecture controls the yield of crops.The tall and loose plant is not suitable to high density crop planting,and it is also easy to suffer diseases and insect pests.The plants with excessive tillers frequently have thin stems and result plant lodging,which causes a risk in keeping a stable production.Strengthening the research on plant architecture is helpful to breed new varieties with stable and high yield.In this project,GWAS with 530 worldwide accessions revealed the different genetic bases in regulating tiller angle and leaf angle in rice.The subfamily members of bHLH transcription factor 16 have the conserved function in regulating the flag leaf angle.It is the first time that we elucidated the mechanism that HD-ZIP transcription factor regulated rice tiller angle and tiller number independently by affecting synthesis of strigalacton and auxin.We unveiled that leaf angle is determined by the process of leaf occipital initiation and development.OsLG2/2L and OsLG1 determine the leaf occipital organogenesis to affect leaf angle.The panicle apical abortion gene PAA1 was cloned.PAA1 mutation caused amounts of H2O2 and led to plant cell death in the panicle top.The mutant paa1 cannot transport the malic acid to the spike located in the panicle top and resulted the spikelet abortion.The important gene of rice architecture development IDS1 was cloned,and its molecular mechanism regulating plant architecture was analyzed.The high-yield rice gene RHY2 was found to regulate the formation of rice plant architecture by regulating the expression of IPA1.A new wheat plant height QTL qPh-6B on chromosome 6B was detected using a RIL population from the hybrid between Konon 9204 and Beijing 411.TraesKN6B-PH was identified as its candidate gene.The high yield gene qGY3 and rhy2-D were isolated,and were introgressed into 3 core restorer lines and 2 important cultivars by consecutive backcrosses.The introgressed materials showed significant higher yields than their correspondent recipients.This study not only riches the regulatory network of plant architecture,but also provides the favorable alleles of genes for tiller angle,leaf angle,spike architecture and plant height,which are the excellent gene resources for developing the ideal crop plant architecture.

光合作用是作物产量形成的物质基础，提高作物光合效率是提高作物产量的重要途径。提高光合作用碳同化产物转运与分配效率也是增加作物产量的有效手段。为了探究如何提高作物光合效率以及分配效率，应用遗传学、组学与分子生物学，克隆了调控光合作用效率(OsPIL14、HPR1、HPR2 和IPS1)、同化产物分配(ES1、PGI和SAG116)等性状的关键基因及调控元件。主要研究结果如下:(1)过量表达HPR1和HPR2可以提高水稻光合效率和产量;(2)过表达OsPIL14促进盐胁迫时水稻中胚轴伸长、提高光合效率;(3)水稻IPS1蛋白与叶绿体发育调节因子GLK1、GLK2蛋白互作抑制GLKs对其靶基因的转录激活作用,IPS1敲除后能提高水稻光合能力、促进籽粒生物量积累。(4)玉米葡萄糖转运蛋白(SWEET1b)编码基因ES1是气孔开放的正调控因子，其基因表达受光合同化物的抑制，光合同化物可以通过ES1间接调控气孔开关。(5)超表达定位于细胞质的磷酸葡萄糖异构酶(PGIc)可以提高植物光合速率、促进淀粉的积累以及生物量。(6)水稻SAG116编码糖苷水解酶调控水稻灌浆效率，其突变体结实率下降，超表达能够提高灌浆效率并提高产量。获得4个SAG116表达水平较高的品系，其中两个品系小区产量分别增加5.9%和6.4%。Photosynthesis is the basis for crop yield.Improving crop photosynthetic efficiency is one of the important approaches to increase crop yield.Moreover,improving the efficiency of the transfer and distribution of photosynthetic carbon assimilation products is also an effective means to increase crop yields.In order to explore how to improve crop photosynthetic efficiency and allocation efficiency,genetics,omics and molecular biology were used to clone the key genes and regulatory elements that regulate photosynthesis efficiency(such as OsPIL14,HPR1,HPR2 and IPS1)and assimilation product distribution(such as ES1,PGI and SAG116).The main research results are summarized as follows:(1)Overexpression of HPR1 and HPR2 can increase the photosynthetic efficiency and yield of rice;(2)Overexpression of OsPIL14 promotes the elongation of rice mesocotyls and increases photosynthetic efficiency under salt stress;(3)Rice IPS1 interacts with chloroplast developmental regulators GLK1 and GLK2,and inhibits the transcriptional activation of GLKs on its target genes.Knockout of IPS1 increases the photosynthetic capacity of rice and promotes the accumulation of grain biomass.(4)The maize glucose transporter(SWEET1b)encoding gene ES1 is a positive regulator of stomata opening,and its gene expression is inhibited by photosynthetic carbon assimilation products,which can indirectly regulate stomatal opening through ES1.(5)Overexpression of phosphoglucose isomerase(PGIc)located in the cytoplasm increases the photosynthetic rate of plants,and promotes starch accumulation and biomass.(6)The glycoside hydrolase gene SAG116 regulate rice filling efficiency in rice,and its mutants have reduced seed setting rate.Overexpression of SAG116 increases filling efficiency and increase yield.Four lines with higher SAG116 expression levels were obtained,and the plot yield of two lines increased by 5.9%and 6.4%,respectively.