Phytophthora sojae Races in Northeast of China and Virulence Evaluation of the Isolates

42 isolates of P. sojae were obtained from diseased soybean plants in 9 counties of Heilongjiang Province and 1 county of Jilin Province in Northeast of China. 11 isolates were classified into 3 races ;the rest that could not be classified due to intermediate reactions were classified into 12 virulence types, suggesting virulence diversity of P. sojae in China. Isolates represented race 1,3 and 8. Race 1 was the most prevalent one.and races 3 and 8 were the first report in China. Our results suggest P. sojae is aboriginal in China.     

Germplasm Evaluation,Inheritance,Molecular Marker and Mechanism of Resistance to Frog—eye Leaf Spot

Soybean frog-eye leaf spot(FLS)has been a major disease and production constralnt in the Northeast of China.The paper reported methods for identifying and evaluating resistant germplasm to the disease,at sometime listed several resistant cultivers or lines which were resistant to both dominant races(1,7race)and the mixture of over 8 races.It indicated that the resistance to race 1 or 7 were due to two different single dominant genes,respectively.And in he fied,there were more races,the resistance showed quantitative character.It was proposed the LTP,which was made according to the sizeand number of lesions could be used as an important index in selecting.Using bulked segregants analyxsis(BSA),the genetic distance between OPSO3 620 and resistant gene to race 7 wer identified 8.7cm.he results showed that the resistant cultivars had less number of stoma,closer arrangement of poliseade tissue and high cotent of wax.     

SPEIPM-based research on drought impact on maize yield in North China Plain

The calculation method of potential evapotranspiration(PET) was improved by adopting a more reliable PET estimate based on the Penman-Monteith equation into the standardized precipitation evapotranspiration index(SPEI) in this study(SPEI PM). This improvement increased the applicability of SPEI in North China Plain(NCP). The historic meteorological data during 1962–2011 were used to calculate SPEI PM. The detrended yields of maize from Hebei, Henan, Shandong, Beijing, and Tianjin provinces/cities of NCP were obtained by linear sliding average method. Then regression analysis was made to study the relationships between detrended yields and SPEI values. Different time scales were applied, and thus SPEI PM was mentioned as SPEI PMk-j(k=time scale, 1, 2, 3, 4,…, 24 mon; j=month, 1, 2, 3,..., 12), among which SPEI PM3-8 reflected the water condition from June to August, a period of heavy precipitation and vigorous growth of maize in NCP. SPEI PM3-8 was highly correlated with detrended yield in this region, which can effectively evaluate the effect of drought on maize yield. Additionally, this relationship becomes more significant in recent 20 yr. The regression model based on the SPEI series explained 64.8% of the variability of the annual detrended yield in Beijing, 45.2% in Henan, 58.6% in Shandong, and 54.6% in Hebei. Moreover, when SPEI PM3-8 is in the range of –0.6 to 1.1, –0.9 to 0.8 and –0.8 to 2.3, the detrended yield increases in Shandong, Henan and Beijing. The yield increasing range was during normal water condition in Shandong and Henan, where precipitation was abundant. It indicated that the field management matched well with local water condition and thus allowed stable and high yield. Maize yield increase in these two provinces in the future can be realized by further improving water use efficiency and enhancing the stress resistance as well as yield stability. In Hebei and Beijing, the precipitation is less and thus the normal water condition cannot meet the high yield target. Increasing of water input and improving water use efficiency are both strategies for future yield increase. As global climate change became stronger and yield demands increased, the relationship between drought and maize yield became much closer in NCP too. The research of drought monitoring method and strategies for yield increase should be enhanced in the future, so as to provide strong supports for food security and agricultural sustainable development in China.     

ISSR Marker and ITS Sequence Study of Melampsora Larici-populina

To compare the differences in intertranslation space of ribosomal DNA （ITS） of Melampsora larici-populina, between the isolates from China and isolates from other countries, this study investigated ITS sequences and ITS polygenetic tree based on 11 isolates that were collected from 5 races in different parts of China. The results indicated that there was no difference among the ITS sequences of 11 isolates from China. The ITS sequence of isolates from China was more homogeneous with that of isolates from Britain compared with France, Germany, and Canada. Intersimple sequence repeat （ISSR） markers were also used to study the genetic division of Melampsora larici-populina, and the results showed that the 11 tested isolates could be divided into Western population and Northern population. Genetic diversity index of race C2 was significantly different from that of races C4, C3, and C1, and no significant differences were observed among the other races. Pathogenicity division of races must not harmonize with their genetic division, except race C2. The ITS region is conservative, and ITS sequence is not fit for studying the differences that existed among the races. ISSR marker can be used for intraspecies population study, and Melampsora larici-populina in China can be divided into two populations.     

Risk Assessment and Zoning of Agricultural Drought Disaster in Heilongjiang Province

In this study,we first zoned the drought degree in the years from 1971 to 2000 in Heilongjiang Province by using precipitation anomaly equation as an indicator,and analyzed the temporal distribution characteristics and laws of arid disaster in different periods.Using the method of human being habitat risk assessment,we further studied and zoned the drought disaster risk index(DDRI)of maize cultivated in 74 stations in Heilongjiang Province via GIS software.The results showed that(1)the occurrence frequency of moderate and heavy drought in Heilongjiang Province was 1970s>1990s>1980s,and(2)the high risk area of drought disaster for maize production mainly assembled in Qiqihar and Daqing regions in west Heilongjiang Province,where agricultural drought should be highly concerned,while low risk and slight risk areas mainly distribute in middle areas and east plain areas in Heilongjiang Province.Our study provided basis for the defense of agricultural drought disaster.     

Pathotype Structure of Magnaporthe grisea in the Fields of Chongyang and Yuan’an in Hubei Province,China

[Objective] This study aimed to explore the pathotype structure of Magnaporthe grisea in Chongyang and Yuan’an in Hubei Province,China.[Method] From the rice-growing fields of Chongyang and Yuan’an in Hubei Province where rice blast occurs frequently,60 isolates which were pathotyped against two sets of host differentials:Chinese host differentials and CO39 NILs,were obtained.Then,20 pathotypes with the six indica host differentials(CO39 NILs) were observed,while 13 pathotypes in four race groups were observed out of the same single spore isolates with Chinese host differentials which consists of three indica cultivars and four japonica cultivars.The diversity of the pathotypes of M.grisea populations tested by CO39 NILs was 2.54 and the pathotype 137.1 occurred at predominantly high frequency(21.67%).The diversity of physiological races of M.grisea populations tested by Chinese host differentials was 1.22 and the race group ZA occurred at predominantly high frequency(73.33%).The diversity of physiological races of M.grisea in Chongyang and Yuan’an were also calculated.Overall,the diversity of pathotypes of M.grisea in Yuan’an was higher than that in Chongyang with the two sets of the host differentials.[Conclusion] This study provided current information on the pathotype spectrum of M.grisea populations in the rice fields of Hubei Province to allow the formulation of viable strategies for blast resistance breeding programs in Hubei Province.     

SPEI_(PM)-based research on drought impact on maize yield in North China Plain

The calculation method of potential evapotranspiration(PET) was improved by adopting a more reliable PET estimate based on the Penman-Monteith equation into the standardized precipitation evapotranspiration index(SPEI) in this study(SPEI PM). This improvement increased the applicability of SPEI in North China Plain(NCP). The historic meteorological data during 1962–2011 were used to calculate SPEI PM. The detrended yields of maize from Hebei, Henan, Shandong, Beijing, and Tianjin provinces/cities of NCP were obtained by linear sliding average method. Then regression analysis was made to study the relationships between detrended yields and SPEI values. Different time scales were applied, and thus SPEI PM was mentioned as SPEI PMk-j(k=time scale, 1, 2, 3, 4,…, 24 mon; j=month, 1, 2, 3,..., 12), among which SPEI PM3-8 reflected the water condition from June to August, a period of heavy precipitation and vigorous growth of maize in NCP. SPEI PM3-8 was highly correlated with detrended yield in this region, which can effectively evaluate the effect of drought on maize yield. Additionally, this relationship becomes more significant in recent 20 yr. The regression model based on the SPEI series explained 64.8% of the variability of the annual detrended yield in Beijing, 45.2% in Henan, 58.6% in Shandong, and 54.6% in Hebei. Moreover, when SPEI PM3-8 is in the range of –0.6 to 1.1, –0.9 to 0.8 and –0.8 to 2.3, the detrended yield increases in Shandong, Henan and Beijing. The yield increasing range was during normal water condition in Shandong and Henan, where precipitation was abundant. It indicated that the field management matched well with local water condition and thus allowed stable and high yield. Maize yield increase in these two provinces in the future can be realized by further improving water use efficiency and enhancing the stress resistance as well as yield stability. In Hebei and Beijing, the precipitation is less and thus the normal water condition cannot meet the high yield target. Increasing of water input and improving water use efficiency are both strategies for future yield increase. As global climate change became stronger and yield demands increased, the relationship between drought and maize yield became much closer in NCP too. The research of drought monitoring method and strategies for yield increase should be enhanced in the future, so as to provide strong supports for food security and agricultural sustainable development in China.     

Comprehensive Evaluation of Tobacco Ecological Suitability of Henan Province Based on GIS

The growth of tobacco is sensitive to environment conditions. The tobacco production is strictly restricted by regional cultivated land. Based on the principal of hiberarchy analysis and fuzzy mathematics and the technique of geographic information system （GIS）, the comprehensive evaluation of tobacco ecology suitability were studied according to the actual circumstances of the whole Henan tobacco planting regions, China. The evaluation index system of tobacco ecology suitability of Henan tobacco planting regions was established by choosing 17 evaluation indexes from 3 respects of climate, soil and landform with Delphi method. Furthermore, the membership function was set up according to the effects of each ecology factors on the growth and quality of tobacco suitability. And the analytical hierarchy process （AHP） was used to determine the weight of indexes by using quantitative analysis. Then the tobacco ecology suitability map of Henan tobacco plantation was drawn with GIS software mapGIS. It is found that the most areas of the western and southern parts of Henan Province, China, are the highly suitable regions, accounting for 22.52% of Henan tobacco planting areas. It is because that there are medium air temperature, sunshine and rainfall, medium soil pH value, and high contents of soil organic matter in the regions. Moreover, the topography is hill and massif, and the height above sea level is between 150-800 m there. Some areas of the southern and middle parts of Henan Province are the suitable ones, accounting for 34.99% of Henan tobacco planting areas. It is because that there are enough rainfall, medium air temperature, high contents of available N and available K in the soil in these regions. There are less suitable regions in the northern and eastern parts of the investigated regions because of drought, too high pH value and CI in the soil and irrigation water, accounting for 35.54% of the whole areas. It can be conducted rapidly and correctly by combining AHP and membership function for comprehensive evaluation of tobacco ecological suitability supported by GIS. There are above moderate ecological suitability for most part of tobacco planting fields in Henan Province. The distributions of tobacco ecological suitability calculated are identical with actual tobacco productivity completely.     

基于灰色关联模型的河南省粮食生产驱动力分析(英文)

Henan Province is an important grain production base, whose stable production is related to the economic development and social stability significantly. To summarize the primary factors of grain producing, we used grey correlation analysis method to analyze 10 correlative factors such as grain yield, grain yield per unit area, effective irrigated area, rural employed persons, grain planting area, consumption of chemical fertilizer in 25 years. The results showed order of synthetic degree of incidence: effective irrigated area>rural electricity consumption>consumption of chemical fertilizer>disaster crop area>grain yield per unit of area>total power of agricultural machinery>afflicted crop area>grain planting area>number of the rural employed persons. Finally, according to synthetic degree of incidence between influential factors and total grain output respectively, a series of measures and the suggestions was proposed for grain production in Henan Province, which will also provide the scientific basis and help for the government correct decision-making.     

Sampling Survey and Identification of Races of Soybean Cyst Nematode (Heterodera glycines Ichinohe) in Huang-Huai Valleys

Soybean cyst nematode (SCN Heterodera glycines Ichinohe) is one of the most important nationwide soybean diseases in China. A total of 38 soil specimens or locations in the area was sampled and tested for SCN races during 2001-2003 for the inspection of race distribution in Huang-Huai Valleys. A map of race distribution was constructed according to the data from both the present study and the published reports cited. Three areas, namely, the area of southeast to Jinan in Shangdong Province; the area of northern Henan Province and its border region to south of Hebei Province; and the area of Luohe, Zhoukou of Henan Province and Fuyang of Anhui Province mainly infested with Race 1 were identified. Race 4 was predominant in Shanxi Province, Beijing and the adjacent area of Henan, Shandong, and Anhui provinces, and the delta of Huanghe River in Shandong Province. Race 2 was mainly found in Liaocheng, Dezhou of Shangdong Province and Shijiazhuang of Hebei Province, and Jiaozuo and Huojia of Henan Province. Race 7 was distributed in the west part of Jiaodong Peninsula of Shandong Province and Kaifeng, Huaxian, Wenxian of Henan Province. Race 5 was found and scattered in Hebei and Henan Province. Race 9 was found in Shangqiu of Henan Province, which was reported for the first time in China. It can be seen that Race 1 and Race 4 were the two predominant races in Huang-Huai Valleys, and that research should focus on developing resistant cultivars of these races. There might exist other races in an area with some predominant races. The race substitution in the past decade was not obviously found, therefore, the results should be meaningful to future breeding for resistance to SCN in Huang-Huai Valleys.     

黄淮地区大豆胞囊线虫生理小种的抽样调查与研究

 【目的】探讨黄淮地区大豆胞囊线虫（Heterodera glycines Ichinohe）的种类及其分布。【方法】2001～2003年在黄淮大豆产区依据Riggs的鉴别模式对38个地点大豆胞囊线虫（SCN）生理小种作抽样调查，并结合文献资料，绘制出黄淮地区大豆胞囊线虫生理小种分布图。【结果】大豆胞囊线虫主要分布在山东、河北、北京、山西大部分地区、河南东部与北部、安徽北部；在山西南部及河南西南部地区的抽样调查中未检测到大豆胞囊线虫。其中1号生理小种主要分布在山东济南以南及以东地区，河南北部与河北南部交界地区，河南漯河、周口及安徽阜阳地区。4号生理小种主要分布在河南、山东、安徽交界地区，山西、北京地区，以及山东黄河三角洲地区。2号生理小种主要分布在山东聊城、德州地区，河北石家庄地区，河南焦作、获嘉地区。7号生理小种主要分布在山东半岛和河南开封、滑县、温县等地。5号生理小种在河南和河北有零星分布。另外，在河南商丘地区新发现有9号生理小种。【结论】黄淮地区的优势小种是1号和4号生理小种，抗线虫育种应该以兼抗1号和4号生理小种为主要目标。各生理小种的分布没有明显分界，优势小种分布区域中存在其他生理小种。在过去的10年中，该地区生理小种的组成相对稳定，本研究结果可供大豆抗线虫育种参考。     

黄淮地区大豆花叶病毒株系的鉴定与分布

2001-2002年采集了黄淮地区四省28个县市的大豆病样591份，经初步繁殖鉴定、生物纯化及组织印迹检测，得到了50个SMV毒株, 采用王修强等筛选的10个鉴别寄主进行接种鉴定，检测到SC-3～SC-9等7个株系群，发现1个新的株系群SC-10。综合本单位1998－2002年的结果，黄淮地区(河南、山东、安徽北、江苏北) 在SC-1~SC-10中，除SC-2未发现外，9个株系群中，以SC-3和SC-7为主，分别占29.21% 和23.60%，SC-4和SC-8其次（10.11%、8.99%）。在各省分布上，河南省有7个株系群，SC-3、SC-4为主，SC-5、SC-7其次；山东省4个株系群，以SC-3为主，SC-8也占相当比重；皖北7个株系群，以SC-7和SC-9为主，其次SC-10；苏北8个株系群，以SC-3和SC-7为主，其次SC-8。按株系群看，SC-3、SC-4各省均有；SC-5、SC-6 、SC-7 在河南、皖北、苏北3地；SC-1、SC-8在河南、山东、苏北3地；SC-9只在皖北发现；SC-10在皖北、苏北2地发现；SC-2在黄淮未发现。     

大豆胞囊线虫抗性位点Rhg1和Rhg4优异等位变异在黄淮育成品种中的分布

【目的】大豆胞囊线虫（soybean cyst nematode,SCN）病是一种重要的世界性大豆病害,种植抗病品种是防治SCN最经济有效的措施。黄淮地区SCN发生普遍,通过对该地区育成大豆品种中抗SCN的基因型分析,为指导抗病品种的合理有效利用提供依据。【方法】利用针对抗SCN主效位点Rhg1和Rhg4开发的4个KASP标记,先对已知抗性表型的ZDD2315、中黄57、山西小黑豆等16份抗病材料和Willams、Lee等3份感病材料进行基因分型,验证所选用KASP标记的有效性;然后对黄淮海育成的豫豆系列、商豆系列、周豆系列等170份大豆品种进行基因型鉴定;选择含有多个优异等位变异的品种,通过温室接种黄淮地区分布较广的2号、4号、5号以及强致病力小种X12,对这些品种进一步进行表型抗性鉴定。【结果】含Rhg1-2(CC) 和Rhg1-5(CC) 优异等位变异的品种分别有5份和6份,含Rhg4-3(TT) 和Rhg4-5(CC) 优异等位变异的品种分别有6份和7份。同时含2个优异等位变异的品种有6份,分别为：开豆4号、商豆1201、鲁0305-2、漯4903、潍豆12和潍豆91861,占所检测品种的3.53%。通过接种鉴定,发现这6个品种对2号、4号、X12号小种均表现不同程度的感病,而鲁0305-2和潍豆91861对5号小种表现高抗（FI分别为（10.00±0.48）和（7.00±0.63））,商豆1201对5号小种表现抗病（FI=（26.20±0.91））,开豆4号、漯4903和潍豆12 对5号小种表现感病或高感（FI分别为（35.00±2.48）、（64.80±3.91）和（58.20±2.19））。【结论】黄淮育成品种中,含Rhg1或Rhg4优异等位变异的品种偏少,育种中应注重优异等位变异位点的引入,结合黄淮地区大豆胞囊线虫发生情况,培育兼抗多个生理小种的大豆品种;这些KASP标记可用于中国大豆资源表型鉴定、抗源的快速筛选。     

我国小麦品种的Rht1、Rht2矮秆基因鉴定及分布研究

利用赤霉酸不敏感性作为矮秆基因的遗传标记,通过系谱分析和基因等位性测验,认定了我国76个优良矮秆小麦品种或材料的赤霉酸不敏感矮秆基因。主要结果如下：（1）在所认定的76个品种中,Rht1基因型的16个,占21%;Rht2基因型的55个,占72%;Rht1+Rht2基因型的5个,占7%。表明我国优良矮秆小麦遗传资源中,Rht2基因型占绝对优势,Rht1基因型次之,Rht1+Rht2基因型较少。（2）Rht1基因型遗传资源主要分布在河南、陕西和河北等省;Rht2基因型遗传资源以山东最多,河北、河南和北京次之,其它省较少。（3）Rht2基因在生产上的累计推广面积为Rht1的2倍;Rht1基因在生产上的累计推广面积以河南最多,安徽、江苏和陕西次之,其它省较少;Rht2基因以山东累计推广面积最大,河南次之,江苏也有较大面积,其它省较少。但它们的利用与育种密切相关。因此,Rht1和Rht2在我国的利用可能没有特殊的地域性。     

中国玉米地方品种种族的遗传变异评估

【目的】通过DNA水平的分子评价,明确中国玉米9个种族的遗传变异,并揭示各种族之间的遗传关系与群体分化特性,为中国玉米种族的形成与演变等相关研究奠定基础,同时也为种族资源的高效利用提供参考。【方法】利用覆盖玉米全基因组的55个SSR标记,对基于中国库存玉米所划分的9个玉米种族的224份代表性材料进行分子鉴定。获得所有标记的片段长度数据后,利用PowerMarker软件（V3.25）中的Summary模块计算224份材料的平均等位变异、基因多样性与多态性信息含量（polymorphism information content,PIC）,并通过重取样策略,利用Wilcoxon秩和测验分析了9个种族在相同样本容量水平上3个遗传多样性参数的差异水平。利用PowerMarker软件中的Phylogeny模块计算了9个种族的欧氏距离,并以此进行种族的聚类分析;利用该软件中的Structure模块对9个种族进行分子变异分析（analysis of molecular variance,AMOVA）,并计算各种族的群体分化系数（F_ST）,以此进行各种族群体分化检测。【结果】55个SSR所检测到的中国9个玉米种族的等位变异、基因多样性与PIC等3个多样性参数的幅度分别为4.42-7.64个/位点、0.5788-0.6532与0.5334-0.6117,平均值依次为11.53个/位点、0.6315与0.5953。西南黄色硬粒种族与衍生种族的平均等位变异相对较高,但基于重取样的分析结果表明这9个种族在这3个多样性参数上的差异均不显著（P＞0.05）。聚类结果显示,9个种族分成了3个类群,其中爆裂种族形成1个独立类群,3个北方种族形成1个类群,剩下的5个种族（3个西南种族、1个糯质种族、1个衍生种族）形成1个类群。AMOVA分析结果表明,9个种族之间的分子变异程度约为3%,远小于这些种族内部所检测到的分子变异（50%）。9个种族的群体分化系数（F_ST）为0.29%-7.63%,其中,西南白色硬粒种族与南方糯质种族、西南马齿种族与西南黄色硬粒种族、西南马齿种族与衍生种族之间的F_ST均相对较小,分别为0.29%、0.70%与0.80%,说明其遗传关系更近。【结论】在长期的人工选择与自然选择过程中,中国玉米9个种族蕴藏丰富的遗传变异。西南白色硬粒种族与糯质种族之间的分化程度远低于其他种族,前者在糯玉米资源的起源进化中可能扮演重要角色;西南黄色硬粒种族和西南马齿种族与衍生种族之间的分化程度很低,表明这2个种族对衍生种族的形成可能有重要作用。     

河北省部分地区马铃薯晚疫病菌生理小种鉴定

利用7个含有显性抗病单基因的鉴别寄主测定了2002年采自河北省的43个马铃薯晚疫病菌菌株的生理小种组成及分布情况。结果表明,被测的43个菌株中共有19个生理小种,出现频率最高的小种为3．4．8．10,占被测菌株的20．9％,其次是小种4．8．10,占被测菌株的14．0％。研究还发现,即使采自同一地块同一品种的不同晚疫病菌菌株也出现了不同的生理小种。     

大麦黄条点花叶病毒的分布及其分离物的遗传多样性

【目的】明确大麦黄条点花叶病毒（Barley yellow striate mosaic virus,BYSMV）在中国北方小麦主产区的分布及其种群遗传多样性,为病害流行预警和防控提供理论依据。【方法】2008-2016年,在河北、山东、江苏、安徽、河南、陕西和山西等7个省66个县/市/区田间,采集了864份疑似病毒病症状的植物样品。提取样品总RNA,利用一步法三重RT-PCR技术检测样品中的BYSMV、水稻黑条矮缩病毒（Rice black-streaked dwarf virus,RBSDV）和北方禾谷花叶病毒（Northern cereal mosaic virus,NCMV）。利用RT-PCR扩增获得BYSMV的L和N基因片段,克隆并测定核苷酸序列,应用MEGA、DnaSP和PAML等软件分析BYSMV分离物的系统进化和遗传多样性特征。【结果】从48个县/市/区采集的336份样品中检测到BYSMV,检出率为38.89%,该病毒主要分布于陕西、河北、山西和山东,另外,河南及安徽北部亦有分布,江苏徐州和邳州仅局部发生。基于BYSMV的L、N基因序列构建的系统发育树均可将分离物划分为2个亚组,亚组I中的分离物其来源涉及全部7个省份,而亚组II中的分离物仅来自陕西和山西2个省,基于L基因序列系统发育分析表明亚组II分离物与伊朗的分离物亲缘关系较近,BYSMV的遗传分化与分离物的地理来源相关,而与寄主植物、发生时间无明显相关性。运用RDP程序包的7个软件进行基因重组分析显示没有支持重组的证据。选择压力分析显示,亚组内和亚组间的ω（dN/dS）值（0.02-0.19）远小于1,表明群体正承受净化选择。L和N基因的单倍型多样性（Hd）值（0.90909和0.99524）均大于0.5、核苷酸多样性（π）值（0.01324和0.01224）均高于0.005,表明中国BYSMV群体遗传多样性丰富。基于L和N基因片段的遗传分化研究显示,东部和西部群体的遗传分化系数（F_ST）值（0.32201和0.37326）均大于0.25,且统计检验差异显著,表明东部和西部的BYSMV群体严重分化;基因流（Nm）值（0.53和0.42）均小于1,说明有限的基因流是促使群体发生遗传分化的主要原因。【结论】BYSMV在中国北方小麦主产区分布广泛,河北、山东、江苏、安徽、河南、陕西和山西等地均有不同程度的发生。BYSMV群体具有丰富的遗传多样性,且东部和西部群体之间存在严重的遗传分化。     

1961-2010年中国主要麦区冬春气象干旱趋势及其可能影响

【目的】近年来,连续发生的冬春连旱事件已经严重威胁到冬小麦的安全生产和粮食增产,本研究以中国主要麦区为研究对象,分析1961-2010年中国北方主要麦区冬春季降水、无降水日数和极端干旱频率的变化趋势及其对当地冬小麦生产的可能影响,揭示冬春干旱在当前气候背景下的演变趋势,为科学应对冬春干旱提供依据。【方法】采用线性倾向估计与Robust F线性显著性检验分析1961-2010年中国北方各站点冬春季降水、冬春季无降雨日数的线性倾向与显著性,揭示冬季、春季和冬春季的降水和无降雨日数的年代际变化趋势;根据气象干旱等级的国家标准GB/T 20481-2006将干旱5个等级中的重旱和特旱定义为极端干旱,基于降水距平的滑动平均,计算1961-2010年各年冬春季极端干旱频次的线性倾向,分析极端干旱发生频次的年际变化趋势和干旱风险剧增区降水的时间变化,揭示干旱时间动态趋势。【结果】(1)1961-2010年,华北为中心的冬麦区冬春气象干旱呈加剧趋势,其中心区域山西、河北和山东西北部冬春两季极端干旱的频次呈现增加趋势,陕西东部和湖北西北部春极端干旱的频次也呈增加趋势;(2)1961-2010年华北冬麦区的冬季降水呈减少趋势,且无降水日数呈增加趋势,即冬季气象干旱呈加剧趋势,其他区域的冬季降水呈增加趋势,无降水日数呈减少趋势;(3)1961-2010年华北冬麦区、黄淮冬麦区中南部和西北春麦区南部的春季降水均呈减少趋势,且无降水日数呈增加趋势,其他区域春季降水呈增加趋势,无降水日数呈显著减少趋势;(4)从重点区域降水的时间动态看,近20来华北地区的冬季和春季降水呈急剧下降趋势,无降水日数呈显著增加趋势,冬春气象干旱风险呈剧增趋势;近50年来黄淮冬麦区和长江中下游冬麦区的冬季降水呈增加趋势,而春季降水呈下降趋势,无降水日数呈增加趋势,长江中下游麦区20世纪70年代中期以后春季降水呈持续下降趋势。【结论】华北地区冬春季降水呈急剧下降趋势,无降水日数呈增加趋势,华北冬小麦冬、春干旱势必由于地下水位的持续下降和抗旱成本的增加而导致干旱风险加大;黄淮冬麦区南部和长江中下游冬麦区的春季降水尽管也呈下降趋势,由于该区域春季平均降水量对小麦来说以偏多为主,降水减少还不会影响到小麦生长,该区域降水的减少可能对冬小麦生长有利;气候干旱区东北和内蒙春麦区、西北春麦区西部50年来的冬春季降水呈增加趋势,有利于春小麦生产。     

近20年黄淮海地区气候变暖对夏玉米生育进程及产量的影响

【目的】探求黄淮海地区近20年气候变暖对夏玉米生长发育进程及产量的影响,为气候变暖背景下夏玉米的高产稳产制定合理的应对措施提供理论依据。【方法】选取黄淮海地区,包括河北、京津地区、河南、山东、安徽和江苏等地区进行区域研究,利用该地区近20年长期观察的气候数据和夏玉米生产数据以及历史产量数据,采用相关分析和非线性多元回归等分析方法,明确气候因子（温度和降水）与夏玉米生育期和产量的关系。【结果】近20年间黄淮海大部分地区夏玉米生长季内区域平均温度呈上升趋势,但存在地区间差异。降水方面,该区东北部的京津-河北地区与山东降水量呈下降的趋势。与1990s相比,2000s河北和山东夏玉米营养生长期天数呈下降趋势,分别下降2 d和1 d,河南呈上升趋势,增加1 d;而生殖生长期呈上升趋势,分别上升4 d和2 d,河南下降1 d。全生育期天数有所增加,平均增加2 d和1 d。河南保持不变。利用F检验法分析审定品种和试验地玉米全生育期线性趋势一致性。结果表明,审定品种生育期和试验地玉米生育期变化呈现一致的趋势,说明品种的变化是影响夏玉米生育期的因子。采用线性偏回归测验法分析品种和气候因子对夏玉米生育期影响重要性。结果表明,气候因子是夏玉米生育期变化的主要因子,影响率占75.3%。黄淮海地区（除江苏外）夏玉米产量以增产为主。非线性分析表明,气温升高会导致黄淮海地区北部的河北与西部的河南夏玉米产量上升,东南部地区各省份夏玉米的减产。降水对该地区干旱少雨的北部地区夏玉米产量有正效应,对湿润多雨的南部地区有负效应。此外,当GDD10上升时,黄淮海地区北部的河北与西部的河南的夏玉米产量会随着上升,而东部和南部的山东、安徽与江苏夏玉米产量将会下降;整个黄淮海地区,当GDD30上升时,会造成全地区夏玉米产量下降,且山东下降最为明显。【结论】黄淮海地区夏玉米的实际生产受气候变暖的影响,夏玉米对气候变暖是逐步适应,可以利用其适应潜力,通过选育生育期长和耐热的夏玉米品种和改进栽培措施来适应气候变暖,从而提高夏玉米产量。