基于杂交种群体的玉米产量及其配合力的全基因组关联分析

【目的】通过分析陕A群和陕B群选育自交系组配的杂交种产量,评估自交系的配合力,并开展以产量和配合力为目标性状的全基因组关联分析,挖掘产量及其配合力的关联位点,为陕A群和陕B群选育玉米自交系的改良及育种中的应用提供依据。【方法】基于NCⅡ遗传设计,以陕A群和陕B群选育的85份优良玉米自交系为亲本,构建包含246份F₁的杂交种群体,在3个环境下进行产量测试,并评估产量的一般配合力和特殊配合力;利用6H90K芯片进行亲本基因型检测,获得63 879个高质量SNP标记,并进行群体遗传特征分析,在杂交种群体推测出高质量SNP标记55 951个,采用加性模型和非加性模型对杂交种产量、一般配合力和特殊配合力开展了全基因组关联分析,并基于B73参考基因组对显著关联SNPs内的基因进行挖掘和功能注释。【结果】3个环境下的产量表现符合正态分布且变异广泛,产量广义遗传力为59.04%,环境效应显著;杂交种产量、一般配合力和特殊配合力三者之间均达到极显著相关性,杂交种产量与特殊配合力的相关性（r=0.95）大于与一般配合力的相关性（r=0.62）;陕A群与陕B群遗传特征具有一定差异,陕A群具有较高的一般配合力。全基因组关联分析分别检测到7、5和9个SNP与杂交种产量、一般配合力和特殊配合力显著相关（-log₁₀(P)>3.86）,其中4个SNP为杂交种产量和特殊配合力共定位,最终锚定了17个关联SNP。对不同性状关联位点的优势等位基因型分析发现,4个GCA关联SNP受加性效应控制,F₁产量BLUE关联位点可分为4种表现形式,以显性效应为主,其杂合基因型为最优等位基因型或次优等位基因型。通过功能注释发现,候选基因在玉米生长发育和籽粒建成中特异表达,例如GRMZM2G165828、GRMZM2G057557均与玉米籽粒发育相关。【结论】一般配合力和特殊配合力共同影响杂交种的产量,特殊配合力效应影响更大;一般配合力和特殊配合力具有不同的遗传基础,可通过有利等位基因聚集提高一般配合力。在F₁杂交种群体采用全基因组关联分析策略可开展配合力相关遗传解析,挖掘产量及其配合力相关遗传位点,可加速关联位点在分子育种中的应用。     

2020年曲阜气候概况及影响评价

利用2020年曲阜国家气象观测站气象资料,分析曲阜市气候特征及评价其影响。结果表明2020年全市平均气温偏高,与常年相比呈上升趋势,降水偏多,暴雨日数7天,较常年偏多2.4天,主汛期（7-8月）降雨多且强度大,照偏多。2020年异常天气频发,灾害时有发生,给农业生产和人民生活造成一定程度的影响,共发生自然灾害5次,其中暴雨洪涝灾害4次,雷雨大风1次,灾害影响了小麦、玉米等农作物的产量,造成了不同程度的经济损失。综合分析,本年气象条件较常年属于正常年份,气候因素同时为农作物的生长创造了有利条件,对农业生产的影响利大于弊。     

ArcGIS在森林公园总体规划专题图制作中的应用

以甘肃省兰州市七里河区石佛沟国家森林公园为例,介绍ArcGIS软件在森林公园总体规划制图中的实际应用,给出成图内容和要求,并详细阐述成图过程中基础资料收集与准备,数据采集与输入,数据编辑与处理,专题图制作与输出等具体步骤。     

Influences of mean advection and simple behavior on the distribution of cod and haddock early life stages on Georges Bank

Results of a modeling study designed to explore the influences of physical advection and certain biological mechanisms on the distribution of cod (Gadus morhua) and haddock (Melarwgrammus aeglefinus) early life stages on Georges Bank are described. Using a late-winter/early-spring 3-D circulation field driven by the M₂ tidal current, mean wind stress and Scotian Shelf inflow, we examine the distribution of cod and haddock larvae spawned on the Northeast Peak of the Bank. The sensitivity to a March-April baroclinic field is also explored. Results indicate that larvae remaining in the surface Ekman layer are generally advected off-bank. However, downwelling associated with Ekman layer convergence near the shelf break provides a mechanism for larvae to exit from the off-bank surface drift. Larvae below the surface layer are transported south-westward along the southern flank of Georges Bank and are retained on the Bank if their position immediately upstream of the Great South Channel is shoalward of (roughly) the 70 m isobath. Within the Great South Channel region and between the 50 and 70 m isobaths, retention can depend on the phase of the tide. Spawning shoalward of the 50 m isobath on the Northeast Peak greatly increases the chances of retention. These results apply to passive larvae and to those with specified vertical distributions and migration based on observations. Directional on-bank swimming at rates of 0.5 to 1 body length per second would substantially enhance shoalward displacement, resulting in larval distributions during the first 2 months that are consistent with field observations.     

A comparison in dogs of medetomidine,with or without MK‐467, and the combination acepromazine‐butorphanol as premedication prior to anaesthesia induced by propofol and maintained with isoflurane

ObjectiveTo compare the haemodynamic effects of three premedicant regimens during propofol-induced isoflurane anaesthesia.Study designProspective, randomized cross-over study.AnimalsEight healthy purpose-bred beagles aged 4 years and weighing mean 13.6 ± SD 1.9 kg.MethodsThe dogs were instrumented whilst under isoflurane anaesthesia prior to each experiment, then allowed to recover for 60 minutes. Each dog was treated with three different premedications given intravenously (IV): medetomidine 10 μg kg^?1 (MED), medetomidine 10 μg kg^?1 with MK-467 250 μg kg^?1 (MMK), or acepromazine 0.01 mg kg^?1 with butorphanol 0.3 mg kg^?1 (AB). Anaesthesia was induced 20 minutes later with propofol and maintained with isoflurane in oxygen for 60 minutes. Heart rate (HR), cardiac output, arterial blood pressures (ABP), central venous pressure (CVP), respiratory rate, inspired oxygen fraction, rectal temperature (RT) and bispectral index (BIS) were measured and arterial and venous blood gases analyzed. Cardiac index (CI), systemic vascular resistance index (SVRI), oxygen delivery index (DO₂I), systemic oxygen consumption index (VO₂I) and oxygen extraction (EO₂) were calculated. Times to extubation, righting, sternal recumbency and walking were recorded. The differences between treatment groups were evaluated with repeated measures analysis of covariance.ResultsHR, CI, DO₂I and BIS were significantly lower with MED than with MMK. ABP, CVP, SVRI, EO₂, RT and arterial lactate were significantly higher with MED than with MMK and AB. HR and ABP were significantly higher with MMK than with AB. However, CVP, CI, SVRI, DO₂I, VO₂I, EO₂, T, BIS and blood lactate did not differ significantly between MMK and AB. The times to extubation, righting, sternal recumbency and walking were significantly shorter with MMK than with MED and AB.Conclusions and clinical relevanceMK-467 attenuates certain cardiovascular effects of medetomidine in dogs anaesthetized with isoflurane. The cardiovascular effects of MMK are very similar to those of AB.     

Site of acid-base relevant ion transfer in the gills of rainbow trout (Oncorhynchus mykiss) exposed to environmental hypercapnia

In order to delineate the contribution of primary vs. secondary circulatory circuits in the gill for acid-base and ionic regulation, the flow and composition of the fluids in the central venous sinus (CVS) and the systemic circuit of rainbow trout were studied by application of a previously developed microcannulation technique during normocapnic and hypercapnic conditions. The average haematocrit (Hct) of blood from dorsal aorta (DA) and sinus venosus (SV) ranged from 20.1 to 26.7%, whereas average Hct in the fluid from the branchial vein (BV), representing drainage from the central venous sinus (CVS), was in the range of 4.2 to 7.0%. Under normocapnic conditions, the largest fraction of cardiac output, 92.9%, was directed through the systemic vascular circuit, whereas the CVS circuit was perfused with 7.1 % of cardiac output. Hypercapnia did not significantly affect the blood flow distribution between the two circuits. The pattern of acid-base regulation in dorsal aortic blood reflected the characteristic response of fish exposed to environmental hypercapnia. Upon initiation of environmental hypercapnia (2% CO₂), plasma P_{CO 2} was elevated in all three flow compartments (CVS, DA, SV), inducing an extracellular respiratory acidosis of about 0.4 pH units. pH and [HCO₃ ^-] values in the DA were consistently lower, than those for both CVS and SV sites throughout the hypercapnic period. During the 8h of exposure plasma bicarbonate concentration was elevated by about 12 mM, complemented by a fall in extracellular [Cl^-] of about 10 mM in all three compartments. The amount of HCO₃ ^- gained at the CVS site during 8h of hypercapnia (3.3 mmol · kg^-1) exceeds the amount accumulated in the extracellular space (2.1 mmol·kg^-1), suggesting the CVS as the main site of ionic acid-base regulation in trout.     

应用高效草坪产业推动土地流转

一项新科技在示范、推广过程中,凭借龙头企业的经济实力,发挥其对草坪产业开发的拉动与扩张能力。采用先示范、获效益、再利用农民专业合作社等多种形式,把农民自愿地组织在一起,从事某一项草坪产业,实现土地的流转和产业专业化,促进农村经济发展、农民增收、农村面貌改善。     

2012年7月我国中东部持续性强降水形成机制分析

利用NCEP/NCAR再分析资料,通过对2012年7月中旬我国中东部地区持续性强降水过程中东亚夏季风系统中主要成员的时空变化特征进行分析.结果表明,此次持续性强降水期间,副高北界、南亚高压脊线及中纬度锋区位置相对稳定,长江中下游地区一直处于南亚高压反气旋环流东侧偏北风与西风槽前偏南风之间的风向开口辐散区中;副高南撤时,强降水主要位于584 dagpm线北侧,副高北抬时,强降水主要位于584 dagpm线南侧;此次持续性强降水发生前期,大气为上干下湿不稳定层结,当西风带低槽频频携带冷空气南下影响,同时低空西南急流反复加强,其出口区左侧较强的风速梯度为暴雨的发生发展提供了动力条件;低层干空气的不断侵入,低槽和低涡间的垂直正反环流促使垂直上升运动维持或发展,进而造成持续性强降水;高空西风急流加强(减弱)超前低空西南急流加强(减弱)2～5 d,对持续性强降水有超前指示意义.     

西北地区中东部秋季连阴雨天气过程与环流背景诊断分析

利用1956～2003年的NCEP资料(2.5°×2.5°)和西北地区5个气象站的逐日降水资料,对出现在我国西北地区中东部(甘肃河东和宁夏南部)的秋季连阴雨天气过程进行了统计分析。结果表明,连阴雨次数在20世纪总体上呈下降趋势;连阴雨的环流形势,在高纬为一槽一脊或二槽一脊,中纬度短波活动较多,青藏高原为一槽区,西北地区中东部受西南暖湿气流的控制且为高能区,短波活动带来的冷空气与西南暖湿气流在西北地区中东部不断交馁,造成降水过程;对流层中部500 hPa欧亚环流形势相对稳定,乌拉尔山的长波脊和中亚低槽维持,该区域的偏南气流为该区输送了大量的水汽,从而形成了西北地区中东部持续的连阴雨天气;当西风带中纬度新疆高压脊建立,副热带高压东移南退时,西北地区中东部的连阴雨天气过程结束。     

低循环风速下木材表层水分蒸发的试验研究

木材干燥过程中,介质循环速度是一个影响木材干燥的重要工艺参数.在木材各含水率阶段,通过试验分析研究不同介质循环速度对木材干燥速度的影响.结果表明,介质循环速度对干燥速度的影响显著,但其影响随木材含水率（MC）的降低而减弱.在低介质循环速度条件下,试件MC大于45％时,表现为木材干燥速度和木材含水率偏差（△MC）随循环风速的增加而增加,呈显著正相关关系;试件MC介于35％ ～ 45％之间时,正相关关系存在但不显著;试件MC小于35％时,干燥室内循环风速的大小不影响木材的干燥速度和木材含水率偏差（△MC）.对试件表层含水率分析,试件表层含水率大于25％时,试件表面循环风速对试件表层含水率的影响显著;试件表层含水率小于25％时,试件表面循环风速对试件表层含水率的影响很小,不同循环风速下试件表层含水率基本一样.