中国水稻生产对历史气候变化的敏感性和脆弱性

有效的适应措施需要了解两类基础信息,一是农业生产所面临的各种气候变异风险,二是作物产量对潜在气候变异风险的反应及其机制.评价作物生产对历史气候变化的敏感性和脆弱性,可以在时间上和空间上揭示气候变化的趋势及作物产量对其的反应,从而为适应行动的全面开展提供基础信息.通过分析1981-2007年水稻生育期3个气候因子(平均温度、日较差、辐射)的变化对水稻产量的影响,评估我国水稻生产对这3个气候因子变化的敏感性和脆弱性及其区域分布状况.结果表明,1981-2007年间我国大部分水稻产区生育期内3个气候因子均发生了明显变化,存在着气候变异风险,其中以最高温的变化最普遍和明显,导致水稻生产中高温热害风险增加.部分区域水稻产量变化与单一气象因子的变化存在着显著的线性相关,这些地区气候因子的变化可以一定程度地解释水稻产量变化趋势,其中产量变化对辐射变化最敏感.当水稻生育期内平均温度上升1℃、日较差升高1℃、辐射下降10％时,我国部分地区水稻产量随之发生了相应的变化,其中辐射降低导致我国水稻生产的脆弱面积最大,其次为日较差.受3种气象因子变化趋势的综合影响,约有30％的水稻产区对1981-2007年的气候变化趋势敏感,少部分地区表现为脆弱,但水稻主产区受到的影响不大,且在东北地区还集中表现出产量增加的趋势,为我国水稻发展提供了契机.     

近20年气候变暖对东北水稻生育期和产量的影响

为探究近20年气候变暖对东北地区水稻生育期和产量的影响,利用东北三省近20年水稻生育期、产量数据和气候观测数据,采用数理统计等方法进行分析.结果表明: 1989-2009年东北三省水稻生长季日平均温度、最高温度和最低温度均呈上升趋势,降水量均呈下降趋势.与1990s相比,2000s黑龙江、吉林和辽宁三省水稻全生育期分别延长了14、4.5和5.1 d.东北地区5、6和9月温度升高可延长水稻全生育期,而7月温度升高则缩短生育期.除黑龙江省外,东北地区的审定品种和观测站点水稻生育期均呈相似的变化趋势,审定品种生育期的延长是导致观测站点水稻生育期延长的主要原因.东北地区日平均温度、最低温度和最高温度的变化均会影响水稻产量,温度上升对黑龙江省的增产效应较明显,尤其是三江平原以西地区.除辽宁省南部以外,其他地区升温均表现为增产.东北地区可以采取育种、栽培和耕作等措施充分挖掘水稻适应气候变暖的能力.
     

基于GIS的黄土丘陵沟壑区作物生产潜力模拟研究

从YIELD模型的来源、输入文件及基本参数,模型中作物生产力计算各个子模型以及计算流程4个方面作了简单的叙述,以黄土丘陵沟壑区典型小流域晋西狼窝沟为例,在地理信息系统（GIS）技术十,应用YILD模型对该流域的作物生产潜力进行了模拟,并从作物类型,地类,耕作措施及气候条件4个方面对影响该流域作物产量的因素进行了分析。结果表明,该模型对不同作物的模拟产量在总体上与实体产量基本相符合,表明模型可以应用于黄土丘陵沟壑区的作物产量模拟之中,对于不同地类来说,坝地的土壤水分和以力条件明显高于梯田和坡耕地,因而坝地的模拟产量地高于梯田和坡地,但三者之间的差距没有实测产量显著,耕作措施是提高作物生产力的有效途径,对地膜覆盖,梯田以及施肥等耕作措施的模拟产量表明,这3种耕作措施均能有效的物生产力;其产量提高率均平均在85％以上,其中以施肥对作物的增产作用最大,增产率高达95％,,这与实测产量资料基本一致;气候条件是影响作物生产的直接因素,模拟结果表明模型对降水量和温度等气候条件十分敏感,不同年份降水量和温度的差异将直接导致作物生产力的显著不同。对YIELD模型的模拟结果分析表明,该模型可以有效地应用于黄土丘陵沟壑区的作物生产潜力研究。     

光温因子与杂交水稻生态群体的产量和品质性状的典型相关分析

以54个杂交水稻组合的F₁生态群体为材料,应用典型相关分析方法分析了光温因子与杂交水稻的产量和品质性状的典型相关性.结果表明,光温因子与杂交水稻的产量构成因素、产量性状和品质性状间均有显著典型相关关系,尤其是营养生长期的光温因子与产量性状的第一典型相关系数为λ₁=0.9975^**,其相关信息占两组性状间总相关信息的99.96%,引起的产量变异为99.50%;光温因子主要通过对每穗实粒数、每穗总粒数和结实率的作用而影响杂交水稻的产量;不同生育期起主导作用的光温因子并不相同,营养生长期为积温和有效积温,生殖生长期为极端温差和日照时数;光温因子对杂交水稻品质性状的精米率和整精米率影响明显;不同生育期影响品质性状的主导光温因子不同,灌浆期前是积温,之后是极端温差和日照时数.     

气候变化对我国华北地区冬小麦发育和产量的影响

验证作物模型在我国华北冬小麦主产区是否适应的基础上,采用作物模型与气候模式相结合的研究方法,定量化地模拟预测了未来100年气候变化对华北冬小麦生产的影响.结果表明,从2000～2004年,华北地区冬小麦产量的模拟值与实测值的变化趋势基本一致,且生育期和产量变化不大.未来100年内华北地区冬小麦的生长期可能会有所缩短,平均缩短8.4 d;产量也会有不同程度的下降,平均减产10.1％.适当采取应对措施可以有效降低冬小麦的减产趋势.     

未来气候变化对福建省水稻产量影响的模拟

为了科学评价未来气候变化对福建省水稻产量的影响,将福建省划分为3个稻区,选取66个样点,7个代表性品种,以及2种典型浓度路径(中端稳定路径RCP4.5和高端路径RCP8.5),利用BCC_CSM(Beijing Climate Center Climate System Model)气候模式,基于这2种典型浓度路径情景RCP(Representative Concentration Pathway)下的气候预估结果,结合作物生长模型CERES-Rice,分雨养与灌溉两种情形,模拟分析气候变化对水稻生产的影响。结果表明:未来气候变化情景下福建省各站点水稻生育期将明显缩短,生育期内平均温度均有所升高;不考虑CO2肥效作用时,无论早稻、后季稻、单季稻,其产量相对于基准年份均普遍减产,减产幅度不超过12%,其中雨养水稻的减产幅度略高于灌溉水稻;不同情景下水稻产量变化也有所差别,其中RCP8.5情景下水稻的减产幅度明显大于RCP4.5情景;而在考虑CO2肥效作用时,模拟结果比较乐观,各研究站点普遍表现为增产,最大增产幅度可达15.2%。     

站点CERES-Rice模型区域应用效果和误差来源

作物区域模拟是利用有限的空间数据,最大限度地反映出生育期、产量等作物性状的时空变化规律.由于目前的作物模型大多是田间尺度的站点模型,把它运用到区域水平的效果如何研究甚少.文章利用CERES-Rice模型,对作物模型在我国的区域应用效果进行了分析.首先利用田间观测数据在各实验点上对模型进行了详细的站点校准,以验证模型在我国的模拟能力;然后以我国水稻生态区(精确到亚区)为单位,运用均方根差(RMSE)法进行了区域校准和验证;最后利用区域校准后的CERES-Rice模型,模拟了1980～2000年的网格(50km×50km)水稻产量,并与同期农调队调查产量进行统计比较,以验证区域应用的效果,为区域模拟的推广和应用提供参考.结果表明:经过空间校准后的CERES-Rice模型,在水稻的主产区1～4区(占种植面积的95%)模拟的平均产量与调查产量相对均方根差在22%以内,两者的符合度也较好,个别区域(5、6) RMSE%在24%～30%之间;1980～2000年水稻各产区模拟的平均产量与调查产量随时间变化趋势也具有一定的一致性;全国1896个网格中,大部分网格(71.01%)模拟的21年水稻年产量与调查产量的RMSE%在30%之内,且大部分分布在水稻主产区,考虑到水稻种植面积的权重后,认为利用区域校准和验证后的CERES-Rice模型进行水稻区域模拟,可以反映出产量的时空分布特征,能够为宏观决策提供相应的信息.但目前区域模拟中还存在着一定的误差,有待今后进一步研究.     

FACE水稻生育期模拟

利用农田开放式空气CO2浓度增高（FACE）技术平台,设置大气CO2浓度比对照高200μmol mol^-1的FACE处理和不同的施N量水平,以水稻钟模型为基础,构建了FACE水稻生育期模拟模型。通过不同年度试验数据的检验,表明模型对CK及FACE条件下水稻不同生育期天数的预测性能好。不同生育期预测误差的根均方差（RMSE）最大为2．64d,最小只有0．15d,且相关系数均达到了极显著水平。说明FACE水稻生育期模型具有较高的预测性和适用性。     

三种光温模型在模拟水稻生育期中的应用与比较

为准确模拟水稻发育进程,本研究根据水稻发育对光温的反应,以双季早稻‘五优157’及双季晚稻‘优选10号’为试材,于2012—2013年在南京信息工程大学农业气象试验站设计水稻大田分期播种试验,同时收集江西省南昌站点2002—2008年双季早稻‘G98-202’以及南康站点2002—2008年双季晚稻‘金优207’的生育期观测数据及同期气象数据,校正光温效应模型、水稻钟模型和有效积温模型以获取模型参数,用独立数据对模型进行检验。结果表明:光温效应模型在模拟水稻播种期-拔节期、拔节期-抽穗期、抽穗期-灌浆期、灌浆期-成熟期的预测值与实测值基于1-1线的决定系数(R2)分别为0.994、0.994、0.988、0.989,且标准回归估计误差(RMSE)均小于4 d;光温效应模型对水稻品种‘五优157’、‘G98-202’、‘优选10号’、‘金优207’从播种期-成熟期的模拟精度比有效积温分别提高了2.42%、4.55%、8.74%和3.16%。研究认为,光温效应模型在模拟江西早稻和晚稻的生育期精度略高于水稻钟模型,有效积温模型精度最差,本研究结果为水稻生育期预测方法的选择提供了参考。     

区域气候变化情景下气候变率对我国水稻产量影响的模拟研究

利用中国随机天气模型将中国区域气候模式ＲＣＭ与作物模式ＣＥＲＥＳ－Ｒｉｃｅ相连接，模拟了３种气候变率（０％，１０％，２０％）水平下未来气候（２０５０年，假定此时ＣＯ２浓度为５５０ｍｇ／Ｌ）对我国水稻主产区（广州，长沙，南京）灌溉水稻和雨养水稻在考虑ＣＯ２肥效与否条件下的产量，模拟结果表明；（１）气候变率对水稻产量的影响因经营方式和研究地区的不同而有差异，对灌溉水稻来说，气候变率对其产量有负面影响，     

光温条件对短光低温不育水稻育性转换的影响

短光低温不育水稻是一类与长光高温不育水稻育性转换特性相反的新种质,通过对分期播种材料自然条件下的育性及人工短光处理后的育性比较分析表明,宜DIS的光敏期为第一苞分化期至第二次枝梗原基和小穗原基分化期（幼穗分化I－III期）,在常温下光敏期的短日处理可使育性趋于不育,但在高温下光敏期短日不育效应被削弱,宜DIS的花粉育性在高,低温作用下育性的均出现下降,根据高,低温影响育性的资料分析得到的敏感期基本一致,即花粉母细胞形成期至花粉内容物充实期（幼穗分化V－Ⅶ期）。     

水稻模型ORYZA2000在湖南双季稻区的验证与适应性评价

校准与验证水稻生长模型ORYZA2000,为模型本地化、区域化研究应用提供依据。本文采用湖南双季稻区作物田间观测数据,结合栽培管理措施、土壤以及同期逐日气象数据等资料对ORYZA2000进行参数校正,调试确定了早稻、晚稻有代表性品种的作物参数;利用独立的数据资料,对双季稻生育期、叶面积指数、生物量、产量等指标的模拟结果进行了详细地验证与适应性评价。结果表明：模型对双季稻品种的生育期模拟较好,开花期和成熟期的相对模拟误差为1—2d;早稻和晚稻叶面积指数的归一化均方根误差（NRMSE）均为24%,地上部总生物量、绿叶生物量、茎生物量和穗生物量的NRMSE值分别为18%、22%、22%、24%和19%、24%、28%、28%,产量的NRMSE值分别为11%和16%。校验的作物参数反映了湖南早稻和晚稻品种的生物学特性,参数值合理、有效。通过校准作物参数,ORYZA2000可较为准确地模拟双季稻生长发育及其生物量的动态累积过程,适应性较强,能够应用于双季稻生产。     

一种紫色水稻的遗传及其在光敏不育系育种中应用的研究

研究表明,本院获得的一种紫色水稻的植株色遗传受控于C、 A、Pl3个独立基因座位上显性基因的互补作用,另有一独立的显性基因对Pl基因的表达起抑制作用。由于该抑制基因在籼稻中的高频率存在,因而,紫稻与一般绿稻品种杂交F1多表现为绿株。紫稻光敏不育(株)系的不育性表达和配合力表现,均可达到与普通光敏不育系相似的水平。本文还讨论了选育籼型紫稻光敏不育系设想的可行性。 Abstract:The inheritance of a purple rice in crosses to green rices was investigated.A group of dominant and interactive genes,C,A and Pl,was found to control the expression of the trait and the other independent inhibitor I-Pl-1 to inhibit the effect of the gene Pl.Because of the wide existence of the gene I-Pl-1 in indica rice,most of F1 plants of the crosses between purple rice and green cultivars were green.The primary study indicated that,for the purple photoperiod-sensitive genic male-sterile lines,the degrees of the sterility and its stability in the sterile stage,and of the fertility in the fertile stage,and the combining ability levels of the purple rice were as high as the degrees and levels for the green rice.A tentative idea on breeding purple photoperiod-sensitive male-sterile lines of indica rice was suggested and its feasibility and advantage was discussed.     

Cytological observation of two environmental genic male-sterile lines of rice.

We report here two environmental genic male-sterilities (EGMS) in rice. These two EGMS rice lines, thermo-sensitive genic male-sterility (TGMS) and photoperiod-sensitive genic male-sterility (PGMS), are controlled by temperature and photoperiod, respectively, in determining their male-sterility. Male-sterility of the TGMS and PGMS was found to be induced when they were grown at 32 degrees C/26 degrees C (day/night) with 14 h daylight, while they were fertile at 26 degrees C/20 degrees C (day/night) with 10 h daylight in a growth chamber. We also examined their anther structures under a light microscope. The light microscopic observation revealed that the EGMS lines showed a complete pollen abortion at the sterile growth condition while they produced normal fertile pollens at the fertile growth condition.     

Effect of Photoperiod Treatments on Phytochrome a Levels and Its mRNA Abundance in Photoperiod-Sensitive Genic Male-Sterile Rice Mutant and the Wild Type

The effect of photoperiod treatments on phytochrome A (Phy A) level and its mRNA abundance in the leaves of a photoperiod-sensitive genic male-sterile mutant (Nongken 58S) and its wild type ("Nongken 58') of Oryza sativa L. was investigated. The top two leaves of each rice shoot were harvested at the end of the last dark phase of 10 cycles during photoperiod-sensitive stage for fertility alteration of the mutant. Phy A was measured by a sandwich enzyme-linked immunosorbent assay (ELISA) using rabbit polyclonal and mouse monoclonal antibodies. Compared with longday (LD) treatment,short day (SD) resulted in 38.5% increase of relative Phy A content in the mutant, only 18.5% increase in the wild type. In an extended darkness (25 h), the accumulation of Phy A also appeared to be more rapid in the mutant seedlings than in its wild type. RNA dot blot analyses with RPA3 (a cDNA clone of rice Phy A) as a probe showed:the abundances of Phy A mRNA in top leaves of Nongken 58S and "Nongken 58" were obviously higher in SD than those in ID at the end of dark phase of 5 d and 10 d photoperiod treatments. Moreover, under SD Phy A mRNA contents in Nongken 58S were more than those in "Nongken 58" during the whole photoperi- od-sensitive stage for fertility alteration. In addition, after 10 cycles of end-of-day far-red irradiations (EOD FR), the heading and flowering date of the mutant was delayed for 2 d. However, EOD FR had little or no effect on male fertility of the mutant.     

Fertility response to photoperiod and temperature in indica photoperiod-sensitive male sterile rice

The aim of this work was to develop a photoperiod-sensitive male sterile rice with stable sterility. We developed Changguang S, an indica rice strain, by using a short critical day length. Differences in the fertility responses of Changguang S strain pollen to temperature and photoperiod under natural and controlled conditions were studied. The results showed that Changguang S strain exhibited stable sterility under long-day and low-temperature conditions (22°C, 15 days). The stability of sterility was significantly higher than that of other such rice strains, Nongken 58S and 7001S. The critical photoperiod for inducing male sterility in Changguang S was 13 h or shorter, and its duration was significantly shorter than that required for rice strains Nongken 58S and 7001S. It is suggested that Changguang S is a typical photoperiod-sensitive male sterile rice strain with a shorter critical day length and a lower critical temperature. It is promising to apply this strain to two-line hybrid rice production.     

光周期对光敏核不育水稻光敏色素A含量及其mRNA丰度的影响

光敏核不育水稻(农垦58S)是我国特有的水稻(Oryza sativa L.)种质材料,光敏色素是光周期诱导其育性转变的受体。报道了育性转换敏感期间的光周期处理对农垦58S及对照“农垦58”叶片中光敏色素A(Phy A)含量及其mRNA丰度的影响。在10个光周期处理的最后一个暗期结束前,收获每株水稻的上部两片叶,用酶联免疫吸附测定法测定Phy A。和长日照(LD)相比,短日照(SD)处理导致农垦58SPhy A相对含量增加38.5％;而“农垦58”只增加18.5％。显然,在较长的暗期中,农垦58S中Phy A的积累比对照快。在水稻幼苗中也得出相似的结果。以光敏色素A基因(phy A)的特异性片段RPA3作探针,用RNA斑点杂交的方法对叶片中Phy A mRNA丰度进行分析的结果表明,光周期处理5d和10d时,两品种水稻的Phy A mRNA丰度都是SD处理的比LD的高,而且SD下农垦58S Phy A mRNA的丰度均比“农垦58”的高。这些结果表明,甲基化水平较低的农垦58S phy A可能比“农垦58”的phy A更活跃地表达。另外,在育性转换敏感期每日主光期结束时(EOD)进行10次短暂的远红光(FR)照射。结果表明,农垦58S植株抽穗和开花期比SD处理推迟2d,而花粉败育率、种子结实率却无变化。暗示农垦58S开花和育性转变过程的光周期反应可能不同。     

Modelling pollen‐mediated gene flow in rice: risk assessment and management of transgene escape

Fast development and commercialization of genetically modified plants have aroused concerns of transgene escape and its environmental consequences. A model that can effectively predict pollen‐mediated gene flow (PMGF) is essential for assessing and managing risks from transgene escape. A pollen‐trap method was used to measure the wind‐borne pollen dispersal in cultivated rice and common wild rice, and effects of relative humidity, temperature and wind speed on pollen dispersal were estimated. A PMGF model was constructed based on the pollen dispersal pattern in rice, taking outcrossing rates of recipients and cross‐compatibility between rice and its wild relatives into consideration. Published rice gene flow data were used to validate the model. Pollen density decreased in a simple exponential pattern with distances to the rice field. High relative humidity reduced pollen dispersal distances. Model simulation showed an increased PMGF frequency with the increase of pollen source size (the area of a rice field), but this effect levelled off with a large pollen‐source size. Cross‐compatibility is essential when modelling PMGF from rice to its wild relatives. The model fits the data well, including PMGF from rice to its wild relatives. Therefore, it can be used to predict PMGF in rice under diverse conditions (e.g. different outcrossing rates and cross‐compatibilities), facilitating the determination of isolation distances to minimize transgene escape. The PMGF model may be extended to other wind‐pollinated plant species such as wheat and barley.     

Strategy and utilization of a herbicide resistance gene in two-line hybrid rice

Hybrid rice plays an important role in China's aim to improve rice production as it accounts for some 50% of rice planting area but produces about 60% of the total rice grain. However, the existing three-line system used in hybrid rice production has its limitations. The two-line system, which makes use of photoperiod-sensitive genic male-sterile (PGMS) and thermo-sensitive genic male-sterile (TGMS) lines to generate the male-sterile parental line, was developed to overcome some of these limitations. The sterility of the male-sterile line of two-line hybrid rice, however, fluctuates when the temperature-sensitive phase of fertility encounters abnormal low temperatures during hybrid seed production, which induces selfing and decreases the purity of hybrid. We describe here the strategy of utilizing a herbicide resistance gene in two-line hybrid rice to eliminate this fluctuation in the sterility of the P/TGMS lines during hybrid seed production and reports the development of the herbicide resistance restorer line Bar68-1 and its herbicide-resistant early season hybrid rice Xiang125s/Bar68-1. When the restorer line and its derived hybrid are herbicide resistant, the selfed seeds can be removed easily from the hybrid by herbicide spraying. A herbicide resistance gene bar was transferred into a restorer line by particle bombardment. The resulting transgenic restorer line Bar68-1 and its hybrid Xiang125 s/Bar68-1 inherited stable herbicide resistance. The purity of Xiang125s/Bar68-1 was increased by spraying the seed bed with herbicide, which resulted in a significant increase in yield, grain quality, and disease resistance in comparison to the controls in a regional trial.     

Ixodes philipi (Acari: Ixodidae): phylogenetic status inferred from mitochondrial cytochrome oxidase subunit I gene sequence comparison

Ixodes philipi ticks were collected from the nest burrows of streaked shearwaters, Calonectris luecomelas, on 3 different islands of Japan (Awashima: 38 degrees 45'N, 139 degrees 24'E; Mikurajima: 33 degrees 52'N, 139 degrees 36'E; and Omorijima: 36 degrees 8'N, 133 degrees 10'E). The mitochondrial cytochrome oxidase subunit I (COI) gene sequence was determined for each tick. The COI sequences of 9 other ixodid tick species also were determined, and they were used for taxonomic positioning of I. philipi. A metastriata tick, Amblyomma triguttatum, was used as an outgroup reference for the analysis. Phylogenetic examination indicated that the I. philipi ticks are on the branch with Ixodes turdus and Ixodes acutitarsus weakly, and the bootstrap value of this branching was low. Three different analyses, maximum parsimony, genetic distance, and maximum likelihood, support this conclusion. To further refine this analysis, 2761 base pairs (bp) of sequence, which included the genes for tRNA(Met), NADH dehydrogenase subunit 2 (ND2), tRNA(Trp), tRNA(Cys), tRNA(Tyr), and COI, were determined and compared for 6 I. philipi ticks from the 3 different collection sites. Although a base substitution (T to C in the ND2 gene for an Awashima tick) and 2 transitions (G to A in the COI gene for 1 Omorijima tick) have occurred, the overall sequences were highly conserved. Preserved mitochondrial sequences in the ticks from 3 widely separated locations suggest the possibility of gene flow, which was probably accomplished by migratory seabirds.