Assessment of the impact of climate change on the latency period of leaf rust on triticale in Poland

ABSTRACT

Disease development in plants is strongly dependent on weather conditions, with temperature playing a particularly significant role by influencing latency period duration. Using two models describing the relationship between latency period and temperature, we performed simulations aimed at predicting changes in the latency period of leaf rust (Puccina recondita f. sp. tritici) on triticale in response to expected climate change. The simulations were based on meteorological data recorded in the period 1986–2005 at locations representing 16 provinces in Poland and based on values obtained after transformation of the observed data to reflect temperature changes under four scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) according to the giss_e2_r climate model. In all scenarios, the results for the two triticale cultivars studied, Witon (vulnerable to P. recondita) and Gniewko (less susceptible), showed a threat of faster development (shorter leaf rust latency period) on triticale triggered by climate change in south-east and south-central Poland than in other regions. The results also showed an increased probability of future regional diversification of leaf rust latency period duration on vulnerable triticale cultivars, opportunities for earlier start of leaf rust epidemics on triticale in Poland and an increase in ?nal disease severity in comparison with 1986–2005.     

不同品种混种对小麦产量及条锈病的影响

用"繁19"、"引11-12"、"川麦107"、"靖麦10号","青春55"、"46548-3"和"安96-8"7个不同小麦品种,组合成6个品种混种的群体,于2003～2004年、2004～2005年、2005～2006年在云南省曲靖市对其产量效应进行了多年多点试验,并在自然发病条件下,调查了6个品种混种群体对小麦条锈病发生程度的影响.结果表明,小麦品种混种的产量效应平均为+3.9%;小麦品种混种在产量上的正效应、0效应,负效应所出现的频率分别为69.4%、8.3%、22.3%;年份、地点等具体环境条件会影响小麦品种混种的产量效应.在小麦条锈病发病强度相对较高的年份,品种混种可降低条锈病病情指数.因此,品种混种在我国一些小麦产区有利用价值.     

Resistance to wheat leaf rust in Aegilops tauschii Coss. and inheritance of resistance in hexaploid wheat

A collection of 164 Aegilops tauschii accessions, obtained from Gatersleben, Germany, was screened for reaction to leaf rust under controlled greenhouse conditions. We have also evaluated a selection of synthetic hexaploid wheats, produced by hybridizing Ae. tauschii with tetraploid durum wheats, as well as the first and second generation of hybrids between some of these resistant synthetic hexaploid wheats and susceptible Triticum aestivum cultivars. Eighteen (11%) accessions of Ae. tauschii were resistant to leaf rust among which 1 was immune, 13 were highly resistant and 4 were moderately resistant. Six of the synthetic hexaploid wheats expressed a high level of leaf rust resistance while four exhibited either a reduced or complete susceptibility compared to their corresponding diploid parent. This suppression of resistance at the hexaploid level suggests the presence of suppressor genes in the A and/or B genomes of the T. turgidum parent. Inheritance of leaf rust resistance from the intercrosses with susceptible bread wheats revealed that resistance was dominant over susceptibility. Leaf rust resistance from the three synthetics (syn 101, syn 701 and syn 901) was effectively transmitted as a single dominant gene and one synthetic (syn 301) possessed two different dominant genes for resistance.     

冬小麦条锈病单叶光谱特性及严重度反演

对冬小麦条锈病胁迫不同严重度(0、1%、10%、20%、30%、45%、60%和80%)的单叶进行光谱测定,其光谱特征明显,随严重度增加,单叶光谱反射率在可见光550～740 nm处增加,差异显著;而近红外平台750～1340 nm反射率也呈上升趋势,差异不显著;中红外1350～1600 nm反射率上升,差异显著.反射率与严重度相关系数在376～1600 nm范围内基本成正相关,达到极显著相关的敏感波段区域为446～725 nm与1380～1600 nm.入选了493、666 nm和1430 nm与严重度的相关系数最高的单个波段,利用相关性最好的666 nm和相关性最弱的758 nm波段组合设计了光谱角度指数SAI(Spectral Angle Index),与严重度建立的模型相关系数较高.并利用连续统去除法对540～740 nm特征反射峰进行归一化定量分析,吸收深度(Depth)与吸收面积(Area)与严重度呈极显著相关,设计的吸收面积指数AAI(Absorption Area Index)与严重度相关系数最好,可较好地反演单叶严重度.结果表明,条锈病单叶光谱特性明显,利用其光谱反射率可以很好的估算单叶严重度,建立的模型具有很高的反演精度.结果对深入研究冬小麦条锈病害遥感监测机理提供了理论依据.     

Identification of powdery mildew and leaf rust resistance genes in common wheat (Triticum aestivum L.). Wheat varieties from the Caucasus, Central and Inner Asia

225 wheat varieties from Kazakhstan, Mongolia and Russia were analysed for their resistance to powdery mildew and leaf rust diseases. A set of 11 different Blumeria graminis f. sp. tritici isolates was used to test for powdery mildew resistance and a set of 10 different Puccinia triticina isolates for leaf rust. 115 cultivars/lines were susceptible to powdery mildew and 32 cultivars/lines showed an intermediate resistance response. 21 cultivars/lines revealed the response pattern of individual resistance genes Pm1, Pm2, Pm3, pm5, Pm6, Pm8, Pm9, Pm17 and Pm22, respectively, therefrom three line showed a combination of two resistance genes and two varieties a combination of three genes. 50 cultivars/lines showed resistance to some specific isolates but an assignment to known resistance genes or gene combinations was not possible, whereas seven lines were completely resistant to all used isolates. The leaf rust test showed that 83 cultivars/lines were susceptible and 11 lines revealed intermediate resistance response. 62 cultivars/lines could be assumed to possess major resistance genes Lr1, Lr3, Lr10, Lr23 and Lr26, respectively, therefrom seven cultivars possessed a combination of two resistance genes. Lr3 was the most widespread resistance gene, occurring in 42 cultivars/lines. 13 lines were completely resistant to all used isolates, however, the response patterns of 56 cultivars/lines did not match to any known gene or gene combination. In 13 varieties the T1BL·1RS wheat-rye translocation could be identified, in five cultivars resistance gene Pm8 was suppressed.     

Transfer of leaf rust and stripe rust resistance from <Emphasis Type="Italic">Aegilops umbellulata</Emphasis> Zhuk. to bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Aegilops umbellulata acc. 3732, an excellent source of resistance to major wheat diseases, was used for transferring leaf rust and stripe rust resistance to cultivated wheat. An amphiploid between Ae. umbellulata acc. 3732 and Triticum durum cv. WH890 was crossed with cv. Chinese Spring Ph ^I to induce homoeologous pairing between Ae. umbellulata and wheat chromosomes. The F₁ was crossed to the susceptible Triticum aestivum cv. ‘WL711’ and leaf rust and stripe rust resistant plants were selected among the backcross progenies. Homozygous lines were selected and screened against six Puccinia triticina and four Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. Genomic in situ hybridization in some of the selected introgression lines detected two lines with complete Ae. umbellulata chromosomes. Depending on the rust reactions and allelism tests, the introgression lines could be classified into two groups, comprising of lines with seedling leaf rust resistance gene Lr9 and with new seedling leaf rust and stripe rust resistance genes. Inheritance studies detected an additional adult plant leaf rust resistance gene in one of the introgression lines. A minimum of three putatively new genes—two for leaf rust resistance (LrU1 and LrU2) and one for stripe rust resistance (YrU1) have been introgressed into wheat from Ae. umbellulata. Two lines with no apparent linkage drag have been identified. These lines could serve as sources of resistance to leaf rust and stripe rust in breeding programs.     

间作系统氮调控对小麦氮钾营养及条锈病发生的影响

通过探讨间作和施氮对小麦植株氮钾养分吸收、分配及条锈病发生的影响,明确氮钾养分吸收和分配与小麦条锈病发生的关系,以期为合理施肥实现控病增产提供理论依据。在云南安宁和峨山两地布置田间小区试验,研究3种施氮水平(0 kg×hm~(–2)、90 kg×hm~(–2)和180 kg×hm~(–2))和2种种植模式(小麦单作、小麦||蚕豆间作)对小麦植株氮钾含量与分配以及小麦条锈病发病率及病情指数的影响。结果表明,施氮增加了小麦产量,且间作增产效应显著;与单作相比,间作小麦平均显著增产31.9%(安宁)和18.0%(峨山);小麦||蚕豆间作产量优势明显,土地当量比为1.20～1.37(安宁)和1.16～1.27(峨山),但间作增产优势随施氮量增加而降低。施氮在提高产量的同时也加重了小麦条锈病危害,随施氮量增加,单、间作小麦条锈病的发病率和病情指数均呈增加趋势。间作有较好的控病效果,与单作相比,间作小麦发病率、病情指数分别显著降低9.6%～22.0%、23.7%～33.7%(安宁)和29.5%～36.5%、29.3%～39.6%(峨山)。施氮增加了小麦植株氮含量,且主要累积在叶片,叶片氮含量占氮吸收总量的41.3%～47.4%(安宁)和35.9%～44.1%(峨山);但间作显著降低小麦植株氮含量,并显著提高钾含量,因而显著降低了叶片氮/钾比。相关性分析表明,小麦条锈病发病率和病情指数与植株氮含量、叶片氮/钾比呈显著正相关,与钾含量呈极显著负相关。施氮增加了小麦植株氮含量,提高了叶片氮/钾比,进而加剧小麦条锈病发生;而间作则通过增加钾含量,降低小麦植株氮含量及叶片氮/钾比,平衡小麦植株内氮钾养分而增强小麦对条锈病的抗性。     

Reaction to powdery mildew and stripe rust in related species and landraces of wheat

Field and controlled environmental tests indicated that the 49 accessions of closely related species and 12 landraces of wheat (Triticum aestivum L. em. Thell.) from the National Gene Bank of China showed different reactions to powdery mildew (Blumeria graminis (DC.) E. O. Speer. f. sp. tritici) and stripe rust (Puccinia striiformis Westend f. sp. tritici) at adult and seedling stages. Unknown Pm genes or alleles were postulated with Triticum baeoticum Boiss. accessions BO 3 and Triticum monococcum L. MO 4 and MO 5 when inoculated with 21 powdery mildew isolates at seedling stage. Fourteen accessions of T. baeoticum, T. monococcum, Triticum durum, and wheat landraces were inoculated with 30 stripe rust isolates at seedling stage. Unknown Yr genes or alleles were postulated with T. baeoticum Boiss. accession BO 5, as well as wheat landraces Xiaobaimai, Laomangmai, and Shaanxibai. Heterogeniety in reaction to powdery mildew isolates and stripe rust races were observed in related species and landraces of wheat.     

施肥对小麦旗叶光合特性的影响研究

用LI-6400观测氮磷钾用量对小麦旗叶光合特性日变化的影响, 试验设4个处理, 分别为高氮低磷高钾(N4P2K2)、无氮无磷高钾(N1P1K2)、无氮高磷无钾(N1P3K1)和高氮高磷无钾(N4P3K1), 试验结果表明: N4P2K2处理对小麦旗叶光合作用有利; 而由于N4P3K1处理缺少钾元素且氮磷过量, 小麦旗叶光合速率(P_n)较低; N1P1K2和N1P3K1处理下光合作用较弱。对同种处理下不同时期小麦旗叶光合速率日变化的比较, N1P3K1处理在3个生育时期的旗叶光合速率差别较大, N4P2K2与N1P1K2处理在各生育期光合作用的差别表现居中, N4P3K1处理各时期的旗叶光合速率差别最小。N1P1K2处理小麦成熟期的光合速率仍然保持较高水平, 钾肥在小麦成熟期影响较大。     

土壤氮磷状况对小麦叶片养分生态化学计量特征的影响

生态化学计量学是研究生态系统能量平衡和多重化学元素平衡的科学,可利用植物体内C、N和P含量及其相互比值（N：P、C：N和C：P,即生态化学计量比）来判断植物生长过程中营养的供给状况。本文通过研究小麦叶片主要元素的生态化学计量比对不同土壤N、P状况的响应,为小麦生产中的精确施肥提供技术指导。选取研究区当家品种弱筋小麦‘扬麦15’和强筋小麦‘镇麦168’为试验对象,采用盆栽试验,设置16个土壤N、P梯度处理,分析不同处理下小麦拔节期、孕穗期和灌浆期叶片N：P、C：N和C：P等生态化学计量比及其相互关系。结果表明：1）在拔节期和孕穗期,土壤N：P范围在7.04~8.73时,两小麦品种叶片的N：P均达到较高水平;而在灌浆期,土壤N：P范围在8.73~10.42时,两小麦叶片的N：P均达较高水平。且小麦叶片N：P与土壤N：P具有极显著的正相关关系,但其相关性随着生育期的推进逐渐降低。2）当土壤处于低N水平时（108.4 mg·kg^-1）,两小麦品种叶片C：N均达较高水平,且其与土壤N：P呈显著负相关,即随着土壤N：P比率增大,小麦叶片中C：N呈减小的趋势。3）当土壤处于低P水平时（29.6 mg·kg^-1）,两小麦品种叶片C：P达较高水平,且其与土壤P含量呈极显著负相关,即随土壤中P的增加,小麦叶片中C：P均呈减小趋势。以上结果表明,土壤中N和P的不同供应水平显著改变不同品种小麦叶片的生态化学计量比,因此,具有稳态特性的生态化学计量比可作为小麦生产中养分调控的重要参照指标并加以应用。     

基于分数阶微分光谱指数的小麦条锈病遥感监测模型构建

为提高小麦条锈病的遥感监测精度,该研究利用分数阶微分能够突出光谱的细微信息以及描述光谱数据间微小差异的优势,在对条锈病胁迫下小麦冠层光谱数据进行分数阶微分处理的基础上,构建了两波段和三波段分数阶微分光谱指数,并将其应用于小麦条锈病的遥感探测。研究结果表明,1.2阶次微分光谱与小麦条锈病冠层病情严重度的相关性最高,较原始反射率光谱、一阶微分光谱和二阶微分光谱分别提高了20.9%、3.9%和20.5%;基于分数阶微分光谱指数的最优分数阶次及其对应波长构建的三波段分数阶微分光谱指数对小麦条锈病的探测能力优于两波段分数阶微分光谱指数,其中分数阶微分光化学指数与冠层病情严重度的相关系数达到0.875;以分数阶微分光谱指数为自变量构建的高斯过程回归（Gaussian Process Regression,GPR）模型对小麦条锈病冠层病情严重度的预测精度优于反射率光谱指数,其训练数据集及验证数据集病情指数（Disease Index,DI）预测值和实测值间的决定系数较反射率光谱指数分别提高了3.8%和19.1%,该研究结果对进一步实现作物健康状况大面积高精度遥感监测具有重要意义。     

Use of a spectrum model and satellite cloud data in the simulation of wheat stripe rust (Puccinia striiformis) dispersal across the Tasman Sea in 1980

Long distance dispersal of plant pathogens has been simulated using different approaches. Models to predict dispersal of airborne spores often use simplified methods to estimate solar radiation in order to estimate mortality of spores. We incorporated a spectrum model into a Lagrangian approach to simulate dispersal of wheat stripe rust from Australia to New Zealand across the Tasman Sea. To estimate cloud cover conditions, satellite data were also used in our study. The combination of a spectrum model and satellite cloud data made it easy to identify sites at which viable spores were deposited. In our study, 0.6% of deposition near New Zealand followed exposure to UV radiation less than our mortality threshold (0.9 MJ m⁻²). Model spores of wheat stripe rust arrived at sites within 40 km from Otama, New Zealand, where wheat stripe rust was first reported in November 1980. It appeared that the uredospores were transported under an overcast cloud condition, which would increase the chance of successful infection on host crops. Further studies on the relationship between solar UV radiation and mortality of pathogen uredospores would facilitate the use of the spectrum model and satellite data to predict dispersal of airborne spores.     

基于图像处理技术的小麦叶面积指数的提取

为了较好地模拟叶面积指数的变化动态,在大田条件下进行试验,获取5个品种5个密度下不同发育期的小麦群体冠层数字图像,并手工测得实际叶面积。通过研究设计了复杂背景下小麦冠层图像叶面指数的有效提取方法,将图像处理得到的叶面积指数数据与实际测得的数据进行拟合建立模型。结果表明：品种、密度和发育期的差异对拟合模型参数影响显著,对模型经过随机抽取样本图像进行假设检验,均能够通过检验。模型的相关系数平方均达到0.86以上,能够实现高精度的小麦冠层叶面积指数的估测。     

我国华北冬小麦生产影响评估模型的研究

研究建立了我国华北冬小麦生产影响评估模型 (WHTMOD) ,该模型由小麦发育期模拟模型、光合生产模拟模型、产量形成模拟模型、土壤水分平衡和N素平衡动态模型等组成 ,综合考虑了光合作用、呼吸作用和同化物在器官中分配等生理过程以及温度、日长、CO2 、水分、N素等因子的影响 ,可模拟小麦生长发育与产量形成动态 ,反映气候异常对研究区域小麦生产的影响 ,模型检验模拟值与实测值相符     

Impacts of climate change on soil nitrogen kinetics and rice production in Andisol paddy fields

We constructed a new rice growth model, SIMRIW_k, and discuss the impact of climate change on the growth and production of rice plants in relation to soil nitrogen (N) kinetics. We developed a model simulating N availability for rice plants associated with soil N kinetics and rice plant N uptake and combined it with the existing rice growth model SIMRIW to construct SIMRIW_k. The model parameters were determined from rice plant growth and soil N experimental data obtained over 25 years under four soil management regimes. SIMRIW_k successfully simulated the annual changes and upward trend observed during the 25 years in all treatments. The relationship between measured yields and SIMRIW_k calculations in all treatments over the 25 years formed one aggregation defined by the regression equation y = 1.00x and showed a significant correlation (r² = 0.894). According to SIMRIW_k, increasing temperature in the cold season increases the formation of easily decomposable organic N produced under dry conditions and N mineralization during the next warm season, suggesting that rice growth is influenced by both warm-season and cold-season temperatures. We forecast rice yield and soil N kinetics from 2016 to 2100 using SIMRIW_k and climate change predictions based on the IPCC’s climate change scenario RCP8.5. Atmospheric warming, a rise in CO₂ partial pressure, and increased soil N mineralization caused by soil warming will increase rice plant growth, but the decreased radiation absorbed owing to the shortened growing season and high-temperature sterility will prevent any significant change in yield. Furthermore, the acceleration of soil organic N decomposition will decrease soil organic N concentrations. Understanding the influences of climate change on soil organic matter kinetics is absolutely critical for predicting the future soil production capacity.     

气候变化条件下中国灌溉面积变化的产量效应

灌溉可以有效缓解气候变化对粮食生产的不利影响。采用中国不同区域2006－2019年实际灌溉用水量,对4个气候模式（GFDL-ESM2M,HadGEM2-ES,IPSL-CAM5-LR,MIROC5）驱动下的3种作物模型（GEPIC、PEPIC和LPJml）的灌溉用水量进行评估,优选模拟结果较好的前5个模式组合,分析RCP2.6和RCP6.0情景下,2021－2050年中国玉米、水稻、大豆和小麦产量变化,评估灌溉面积扩张的增产效应。结果显示：未来气候变化下,2021－2050年降水量的增加使得中国水稻和大豆以及北方地区玉米和小麦产量均呈现增长趋势,其中东北80%左右的地区和西北70%左右的地区玉米产量将提高0.2～0.8 t/hm2,东北85%左右的地区水稻和大豆增产幅度分别超过1.0、0.5 t/hm2,东北90%左右的地区和西北75%左右的地区小麦产量增幅分别介于1.0～2.0、0.5～1.0 t/hm2之间。降水量的减少使得西南南部地区的玉米和小麦产量均下降0.2 t/hm2左右。不同区域玉米和小麦的增产效应差异明显,由于北部地区光热条件较差、小麦基础产量较低,使得小麦灌溉增产潜力（1%～11%）以及增产效率（（0.12±0.06）kg/m3）均较高,北部地区小麦的灌溉面积扩张可有效应对气候变化的不利影响。     

主要生育期气候变化对河南省冬小麦生长及产量的影响

为分析不同生育期气候变化对冬小麦生长及产量的影响,本研究选择河南省30个农业气象观测站1961—2014年气象资料、1981—2014年冬小麦发育期及产量资料,采用数理统计与DSSAT-CERES Wheat模型模拟相结合的方法,分析了冬小麦播种—返青、返青—抽穗、抽穗—成熟3个时期的气候变化特征及其对生育期和产量的影响。结果表明:研究区气候变化的显著特征是播种—返青期日照时数按40.09 h·(10a)~(-1)的速率显著减少(P0.05),返青—抽穗期平均日最高气温和平均日最低气温同时大幅升高。冬小麦幼穗分化随着抽穗前日最低气温的升高按2.9 d·(10a)~(-1)的速率而提前结束,返青前气候变化对后续生育进程有持续影响,气象因子与播种—抽穗期、播种—成熟期持续日数以负相关关系为主。两种分析方法均表明:当前河南麦区播种—返青期气候变化对产量的影响不大,在一定范围内甚至有增产作用,气象因子贡献率平均为0.758;返青—抽穗期气候变化使穗密度和穗粒数平均减少2.74%和3.94%,大于抽穗—成熟期。不同生育期气候变化情景下,冬小麦高产和稳产均受影响,代表站点播种—返青、返青—抽穗、抽穗—成熟期分别平均减产1.6%、6.3%和4.8%,其中播种—返青、抽穗—成熟期影响产量的关键气象因子是日最高气温,而返青—抽穗期是日最低气温。     

Predicting the effects of climate change on fire frequency in the southeastern Canadian boreal forest

Although an increasing frequency of forest fires has been suggested as a consequence of global warming, there are no empirical data that have shown climatically driven increases in fire frequency since the warming that has followed the end of the “Little Ice Age” (～1850). In fact, a 300-year fire history (AD 1688–1988) from the Lac Duparquet area (48°28′N, 79°17′W) shows a significant decrease both in the number and extent of fires starting 100 years ago during a period of warming. To explore this relationship between climatic change and fire frequency we used daily data from the Canadian Atmospheric Environment Service's General Circulation Model to calculate components of the Canadian Forest Fire Weather Index (FWI) System for the 1xCO₂ and 2xCO₂ scenarios. The average FWI over much of eastern Canada, including the Lac Duparquet region, decreased under the 2xCO₂ simulation, whereas FWI increased dramatically over western Canada. According to these results, fire frequency would decrease over the southeastern boreal forest which is in agreement with the empirical data from the fire history. Our results stress the importance of large regional variability and call into question previous generalisations suggesting universal increases in the rate of disturbance with climate warming.     

Assessing the effects of climate change on the phenology of European temperate trees

Modelling phenology is crucial to assess the impact of climate change on the length of the canopy duration and the productivity of terrestrial ecosystems. Focusing on six dominant European tree species, the aims of this study were (i) to examine the accuracy of different leaf phenology models to simulate the onset and ending of the leafy season, with particular emphasis on the putative role of chilling to release winter bud dormancy and (ii) to predict seasonal shifts for the 21st century in response to climate warming.Models testing and validation were done for each species considering 2 or 3 years of phenological observations acquired over a large elevational gradient (1500 m range, 57 populations). Flushing models were either based solely on forcing temperatures (1-phase models) or both on chilling and forcing temperatures (2-phases models). Leaf senescence models were based on both temperature and photoperiod.We show that most flushing models are able to predict accurately the observed flushing dates. The 1-phase models are as efficient as 2-phases models for most species suggesting that chilling temperatures are currently sufficient to fully release bud dormancy. However, our predictions for the 21st century highlight that chilling temperature could be insufficient for some species at low elevation. Overall, flushing is expected to advance in the next decades but this trend substantially differed between species (from 0 to 2.4 days per decade). The prediction of leaf senescence appears more challenging, as the proposed models work properly for only two out of four deciduous species, for which senescence is expected to be delayed in the future (from 1.4 to 2.3 days per decade). These trends to earlier spring leafing and later autumn senescence are likely to affect the competitive balance between species. For instance, simulations over the 21st century predict a stronger lengthening of the canopy duration for Quercus petraea than for Fagus sylvatica, suggesting that shifts in the elevational distributions of these species might occur.