Genetic bases of source-,sink-,and yield-related traits revealed by genome-wide association study in Xian rice

The source-sink relationship determines the ultimate grain yield.We investigated the genetic basis of the relationship between source and sink and yield potential in rice.In two environments,we identified quantitative trait loci(QTL)associated with sink capacity(total spikelet number per panicle and thousand-grain weight),source leaf(flag leaf length,flag leaf width and flag leaf area),source-sink relationship(total spikelet number to flag leaf area ratio)and yield-related traits(filled grain number per panicle,panicle number per plant,grain yield per plant,biomass per plant,and harvest index)by genome-wide association analysis using 272 Xian(indica)accessions.The panel showed substantial variation for all traits in the two environments and revealed complex phenotypic correlations.A total of 70 QTL influencing the 11 traits were identified using 469,377 high-quality SNP markers.Five QTL were detected consistently in four chromosomal regions in both environments.Five QTL clusters simultaneously affected source,sink,source–sink relationship,and grain yield traits,probably explaining the genetic basis of significant correlations of grain yield with source and sink traits.We selected 24 candidate genes in the four consistent QTL regions by identifying linkage disequilibrium(LD)blocks associated with significant SNPs and performing haplotype analysis.The genes included one cloned gene(NOG1)and three newly identified QTL(qHI6,qTGW7,and qFLA8).These results provide a theoretical basis for high-yield rice breeding by increasing and balancing source–sink relationships using marker-assisted selection.     

人地协调视角下农村居民点利用质量评价与提升策略

农村居民点高质量利用是乡村振兴的一种具体表现，综合开展农村居民点质量评价、全面改善质量障碍要素是科学编制村庄规划和优化农村要素配置的基础。该研究以北京市平谷区为例，从土地集约利用和人居环境品质相互协调的视角界定农村居民点利用质量内涵并构建评价体系，综合运用熵权-TOPSIS法、变异系数修正的弹性系数法和障碍度诊断模型，对农村居民点利用质量进行评价并提出相应的提升策略。结果表明：1）平谷区农村居民点土地集约利用水平中等偏高，人居环境品质和农村居民点利用综合质量则中等偏低。2）平谷区农村居民点类型表现为中等质量主导、高质量次之、低质量偏少，对应着从脱钩F弱型、脱钩T弱型、正向挂钩F强型、负向挂钩F弱型、正向挂钩T强型、负向挂钩T弱型、正向挂钩T-F同强型、负向挂钩T-F同弱型的村庄数量依次降低。3）平谷区农村居民点高质量利用的障碍要素主要体现在规模强度、空间布局、生活环境和生产环境4个维度，从高质量到低质量利用类型，障碍因素数量增多、作用程度逐渐增大。4）平谷区应充分发挥生态环境优势，在"整体化、集约化、人本化和善治化"战略导向下，按照"高质量利用类适当优化、中等质量利用类同步调控、低质量利用类系统整治"策略，分类有序地推进农村居民点质量提升。     

农产品质量安全有效治理的路径浅析

食品安全问题是有关国计民生的重要问题，关系着广大消费者的切身利益。农产品作为各 类食品的源泉，其质量安全监管及治理是保障食品安全的基本要求。本文就当前农产品质量安全面 临的主要问题做了一些浅析，提出了治理途径，以期对于农产品质量安全的有效治理提供一些思路。     

乡村地域系统环境污染演化过程及驱动机制研究

乡村地域系统转型发展过程中面临严峻的资源供给紧张、生产环境恶化、生态环境污染与功能退化等问题。乡村污染治理是实现国家乡村振兴战略与乡村系统可持续发展的重要保障。基于乡村污染物类型梳理与污染演变过程刻画，探讨了乡村地域系统环境污染的驱动机制。结果表明：从污染属性来看，乡村地域系统的污染物主要包括水体、土壤和大气污染物；在时间上，污染物从单项无机物逐渐演变为无机有机复合物，致使乡村地域系统环境污染从单一污染逐渐演变为复合污染和立体污染；在空间上，从城市近郊村、远郊村到一般农区的污染源与污染程度呈现递减趋势；乡村内部资源利用、生活和生产活动、污染治理体系，外部工业化、城镇化、全球变化、信息化等共同驱动乡村地域系统污染。未来应选择典型样带-样区-样点，研究不同乡村地域系统污染现状格局、驱动机制及其资源环境效应模拟评价，推动乡村污染治理与政策创新。     

Agricultural extension approach: evidence from an Integrated Soil Fertility Management Project in Ethiopia

Agricultural extension is an approach to rural development and agricultural transformation in which training, demonstration and technology transfer are key to reducing rural poverty, ensuring food security, and sustainably managing natural resources. During recent decades, different extension approaches have been tested and validated by the Ethiopian government and non-governmental organizations to stimulate participation in the agricultural extension system (AES). The most recent was a German-funded project entitled “Integrated Soil Fertility Management Project” (ISFM⁺), which employed a novel approach to piloting and upscaling proven technology and best practice. The purpose of this study was to analyze and document the modalities of ISFM⁺ and illustrate its effects on technology uptake and dissemination. The study used a mixed methods approach to collect data. ATLAS.ti and SPSS were used for data management and analysis. Farmer Research and Extension Groups and Farmer Field Schools were found to be central to the participation process. Also, the ISFM⁺ was found to aid technology transfer and helped to increase grain and residue yields as well as farmer livelihoods. Based on these empirical findings, it is argued that the ISFM⁺ approach and technology should be integrated and institutionalized in the mainstream AES in order to promote their extensive application.     

68个大豆品种(系)遗传多样性分析

为保持大豆杂种优势利用中亲本的遗传差异,利用64对SSR引物对68个大豆品种(系)包括53个中国品种(系)和15个美国品种进行遗传多样性与亲缘关系分析。结果表明,共检测到375个等位基因变异,平均每个位点检测到的等位变异数为5.86个,变化范围为2～12个,其中53个中国品种(系)检测到373个等位基因变异,平均为5.83个,变化范围为2～12个,15个美国品种检测到288个等位基因变异,平均为4.50个,变化范围为2～9个;总的位点多态性信息含量(PIC)变化范围为0.366～0.900,平均为0.677,其中53个中国品种(系)变化范围为0.370～0.909,平均为0.682,15个美国品种变化范围为0.309～0.817,平均为0.590。聚类分析表明:68个大豆品种(系)的遗传相似系数(GS)变幅为0.529～0.973,平均GS值0.707,在相似系数0.65处,可将供试的品种(系)聚为2大类,第Ⅱ类在相似系数0.69处又可分为5个亚类。     

南疆植被总初级生产力对区域降水的响应规律

为研究总初级生产力(Gross primary productivity,GPP)对区域降水的响应规律,本研究通过对南疆地区喀什、阿克苏、和田3个市2000—2014年的GPP进行分析,得出GPP的时空分布规律,进而与2000—2011年同期的降水进行耦合分析,以探寻植被GPP与降水之间的响应关系,从而为南疆地区植被生态保持和可持续发展提供依据。结果表明:1)从时间尺度来看,GPP呈现出与季节相关的波动性,年均GPP的极值点基本出现在每年的7月;2)在空间分布上,和田地区的GPP在空间上呈现北低南高的空间格局,阿克苏地区的GPP呈现北高南低的空间格局,并且在数值上存在较大的差异性,喀什地区的GPP呈现北高南低的空间格局,西北部GPP分布比较集中并有较高的值;3)变化趋势上,和田地区呈现上升趋势、阿克苏地区整体比较稳定、喀什地区呈现上升的趋势;4)研究区域内GPP与降水之间均为正相关关系。当降水滞后1个月时,和田及喀什GPP与降水之间的相关系数显著提高,但是阿克苏地区没有表现出时滞性,说明响应关系更加明显。     

数字治理下突发公共事件中农村社区治理策略研究

农村社区疫情防控工作的创新点在数字治理。以北京市部分农村社区的具体案例为研究对象，并结合浙江等省市的精密型疫情防控措施，提炼了应用风险放大框架进行数字治理的关键点，并建立了信息传播机制和放大反应机制的分析模型，最后从流程管理、设备开发、反馈渠道和科学研究四个方面提出农村社区数字治理的建议。     

乡村振兴的难点及对策分析

乡村振兴是我国新时代意义长远的全局性事业，面临诸多难点，需综合施策，促进乡村持续兴旺发展。建议通过改善乡村人居条件，打破非农居民下乡定居政策壁垒，破解活力人口流失难点；不拘一格组建村班子，解决村支“两委”战斗力不强难点；发挥村骨干作用，公开透明处理乡村事务，融洽干群关系，解决干群疏离难点；以保障农民权益为出发点协调农民流转意愿，解决土地统一流转难点；政策引导，推动资源按市场规律下乡，解决资源下乡难点。