干旱是当今世界出现频率最高、持续时间最长、危害范围最广的重大气象灾害，对全球农业、生态、社会发展和国民经济等影响巨大而广泛。农业旱灾是影响农业生产的重要因素，农业生产关乎着国家粮食安全。我国是一个农业大国，同时也是一个旱灾频发的国家，深入了解农业干旱灾害的成因、影响特征、旱灾强度、严重程度以及作物致灾的生理过程和机理等是提升农业干旱灾害监测预测预警水平、减轻和防御灾害损失、提高国家粮食安全生产需要解决的重要科学问题。本文综合回顾了国内外不同程度的农业干旱及其对粮食生产影响的最新研究进展，从农作物形态、生理、细胞和分子水平等方面探究了干旱影响特征及机制，围绕粮食生产如何有效应对农业干旱问题，评述了当前农业干旱监测的主要指标、方法、预警系统等，针对农业可持续发展和干旱新特征，讨论了当前防旱减灾和农业干旱应对的现状，强调了适应与减缓并举的一系列干旱应对措施，在此基础上结合国家、区域和行业发展需求提出了今后应着重加强的重要科学问题、研究对策及学科发展展望。

玉米是全球也是中国第一大作物，在保障国家粮食安全中占有重要地位。当前，面对经济社会的快速发展和人增地减、资源紧缺、生态环境恶化等一系列突出问题，玉米栽培学科正面临着严峻挑战和新的历史发展机遇，在此重要历史关头，回顾中国玉米栽培研究历程和科技进展，探索未来发展方向具有重要的意义。分析表明，经过60年不懈努力，玉米栽培研究的目标已由产量为主向高产、优质、高效、生态、安全等多目标协同发展，研究内容不断拓宽与深入，形成了具有显著中国特色的玉米栽培科学与技术体系。进入21世纪以来，玉米栽培研究进入黄金发展期，在栽培理论、关键技术创新与应用方面取得一系列重要突破，在保障国家粮食安全中发挥了重要的作用。围绕未来玉米生产对科技的需求，依据现代科技的发展趋势，笔者认为高产、优质、高效、生态、安全仍将是未来玉米栽培研究的主要目标，并提出今后20年重点研究的方向与任务：一是继续探索不同生态区玉米产量潜力及突破技术途径，努力提高单产水平；二是转变生产方式，围绕籽粒生产效率，以提高资源利用效率和劳动生产效率为目标，降低生产成本，提高商品质量，增强玉米市场竞争力；适度发展青贮玉米和鲜食玉米等，促进玉米生产向多元化方向发展；三是应对全球气候变化，开展抗逆、减灾、稳产理论和技术研究，实施保护性耕作，实现玉米可持续生产；四是依托现代信息技术，开展智能化栽培技术研究，实现玉米精准生产与管理；五是强化栽培学科基础研究，玉米设计栽培，夯实玉米科技研究和生产发展基础。

【目的】定量化解析主要栽培措施对春玉米产量的贡献,探索北方春玉米缩差增产增效技术途径。【方法】通过综合分析2000年以来我国北方春玉米在品种耐密性、种植密度、耕作方式、养分管理、病害防治等114篇论文数据,同时结合大田栽培措施因子替换试验,定量解析主要栽培措施对春玉米产量的贡献及其优先序。【结果】文献统计分析结果与大田栽培因子替换试验结果基本一致,当前生产主要应用的5项主要栽培措施对春玉米产量贡献的优先序为种植密度、养分管理、品种耐密性、防病（兼化控）、耕作方式,对产量的贡献率分别为12.6%、9.2%、6.7%、6.3%和5.5%,对氮肥偏生产力（PFP_N）的贡献分别为16.7%、4.1%、3.4%、3.8%和3.3%。各措施因子对玉米产量差的影响主要通过影响群体物质生产能力和群体库容量实现,当群体LAI饱和后,如何优化群体同化性能、提高光能利用效率和单位叶面积籽粒生产效率是缩差增产的关键。【结论】产量和资源效率协同提高15%—20%的高产高效目标,通过密度和养分管理这2项措施的优化即可实现,若要使产量和资源效率均增加30%—50%,则需要综合优化至少4个因子甚至全部5个因子。

Germplasm, genetics, phenotyping, and selection, combined with a clear definition of product targets, are the foundation of successful hybrid maize breeding. Breeding maize hybrids with superior yield for the drought-prone regions of the US corn-belt involves integration of multiple drought-specific technologies together with all of the other technology components that comprise a successful maize hybrid breeding programme. Managed-environment technologies are used to enable scaling of precision phenotyping in appropriate drought environmental conditions to breeding programme level. Genomics and other molecular technologies are used to study trait genetic architecture. Genetic prediction methodology was used to breed for improved yield performance for drought-prone environments. This was enabled by combining precision phenotyping for drought performance with genetic understanding of the traits contributing to successful hybrids in the target drought-prone environments and the availability of molecular markers distributed across the maize genome. Advances in crop growth modelling methodology are being used to evaluate the integrated effects of multiple traits for their combined effects and evaluate drought hybrid product concepts and guide their development and evaluation. Results to date, lessons learned, and future opportunities for further improving the drought tolerance of maize for the US corn-belt are discussed. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

【目的】研究密度对高产玉米（＞15 000 kg•hm-2）产量及其构成因子的影响，揭示高产玉米产量形成机制，为玉米持续稳定高产提供依据。【方法】连续两年在新疆和宁夏高产玉米区，以郑单958为试材，以1.5万株/hm2为一个密度梯度，设置从1.5万株/hm2至18万株/hm2不同密度处理，充分满足水肥需求，进行高产栽培实践，在实现高产基础之上分析其产量及产量构成因子特征。【结果】两年多点共68个处理，最低和最高单产分别为7 675.5和20 503.5 kg•hm-2，其中有47个处理达到15 000 kg•hm-2以上的产量；对产量构成特征的分析表明，要达到15 000 kg•hm-2以上的高产，最低、最高密度分别为5.25万株/hm2和16.28万株/hm2；最低、最高收获穗数分别为6.66万穗/hm2和13.84万穗/hm2；最低、最高穗粒数分别为365和657粒；最低、最高千粒重分别为237和404 g。【结论】密度与单产呈抛物线关系，以10.5万株/hm2密度处理单产最高；随着产量的提高，种植密度、单位面积穗数、穗粒数和千粒重表现出最适值范围变窄的趋势。随种植密度增加，单位面积穗数呈增加趋势，穗粒数和千粒重呈下降趋势，而单位面积粒数呈增加并趋于不变趋势。

国内高效节水灌溉水肥一体化技术因其节水、节肥、高效等特点得以快速推广及大面积应用。首先阐述了目前国内高效节水灌溉水肥一体化技术模式现状，然后简要回顾了高效节水灌溉水肥一体化技术对玉米作物产量、水分和肥料利用效率的影响，分析了高效节水灌溉水肥一体化技术目前存在的主要问题，提出了相应的建议对策并展望了今后需要进一步关注的方向，以期为提升玉米高效节水灌溉水肥一体化技术应用提供技术参考。

为揭示不同倍性小麦生长发育、产量性状及水分利用对灌浆期水分亏缺响应的差异, 选用二倍体野生一粒小麦(Triticum boeoticum)、栽培一粒小麦(T. monococcum), 四倍体野生二粒小麦(T. dicoccoides)、栽培二粒小麦(T. dicoccon), 和两个普通六倍体小麦(T. aestivum)品种‘长武134’和‘陕253’ 6个小麦品种作为供试材料。采用盆栽控水的方法, 测定和分析了不同灌浆期土壤水分条件下小麦株高、旗叶叶面积、穗长、根干重、地上生物量、根冠比、千粒重、粒数、产量、收获指数、蒸腾耗水量和水分利用效率等性状的变化。在小麦染色体倍体由二倍体向六倍体进化的过程中, 小麦地上生物量、千粒重、穗粒数、产量、收获指数和水分利用效率都显著增加。随着土壤水分从正常→中度亏缺→重度亏缺的减少, 收获指数先增大后减小, 分别为41.26%、42.48%和38.19%; 生物量水分利用效率逐渐增大, 分别为2.39、2.43和2.53 g·kg–1; 产量水分利用效率分别为1.05、1.10和1.04 g·kg–1。在灌浆期水分条件是影响收获指数和水分利用效率的关键因素之一。灌浆期的水分亏缺有利于六倍体小麦的收获指数和四倍体的生物量水分利用效率的提高。中度的水分亏缺有利于四倍体和六倍体产量水分利用效率的提高。

玉米作为我国种植面积最大、总产最高的第一大粮食作物，对我国粮食安全、饲料保障都至关重要。在耕地资源日趋紧张的形势下，未来我国粮食扩大面积的空间有限，产能提升主要依靠单产提高。2023年中央一号文件明确提出要全力抓好粮食生产，开展吨粮田建设，实施玉米单产提升工程。玉米超高产是优良品种、生产条件和栽培管理技术等最高水平的体现，本文全面综述了我国玉米超高产研究的政策支持、高产纪录现状、超高产田的分布及气象特点、高产创建的技术要点。在此基础上，从增加科研投入加强新品种选育、加强栽培技术集成进行示范推广、加强农田基础设施建设等方面提出了我国玉米大面积高产创建的建议。

[目的]针对土壤高湿和干旱影响夏玉米籽粒灌浆并对其造成减产的灾害问题,为了揭示其致灾的生理机制,[方法]2016年在夏玉米生长季通过人工控制土壤水分,设计了土壤高湿、干旱和对照3种处理,在玉米灌浆期测定叶片的光合特性日变化、光饱和点和光补偿点、夜间叶片暗呼吸等。[结果]结果表明：对照玉米叶片的净光合速率日变化曲线呈双峰型,即“M”型,而高湿处理被弱化为单峰型,干旱处理全天持续走低。气孔导度(Gs)和蒸腾速率(Tr)的日变化规律一致,呈显著正相关；胞间CO2浓度(Ci)和水分利用效率(WUE)的日变化曲线呈反向变化,呈显著负相关。高湿处理的叶片暗呼吸比对照提高0.5800-0.7767μmolCO2m-2.s-1,干旱处理比对照降低0.1767-0.4933μmolCO2m-2.s-1,可能因为土壤高湿情况下,玉米叶片等绿色器官呼吸作用强导致果穗籽粒养分积累少进而造成减产；分析光饱和点和光补偿点发现,高湿处理光合作用有效利用光强的区间拉大,干旱胁迫下,光合作用有效利用光强的区间缩小,这可能是玉米灌浆期干旱造成减产的主要生理原因。

The kernel setting of maize varies greatly because of the timing and intensity of water deficits. This variation can limit leaf productivity (source), the translocation of assimilated sugars (flow), and yield formation (sink). To explain the decline in kernel setting of maize under water deficits from the perspective of source-flow-sink, a 3-year experiment was conducted under a rain shelter. Five water regimes were studied. One regime included well-irrigated (CK) treatment. Four regimes involved water deficits: irrigation was withheld during the 6-to 8-leaf stage (V6-8), the 9- to 12-leaf stage (V9-12), the 13-leaf stage to tasseling stage (V13-T), and the silking stage to blister stage (R1-2). Water deficit effects on kernel setting began when the water deficit occurred at V9 and became more significant with time. Kernel weight was reduced by 12 and 11% when there were water deficits during V9-12 and V13-T, respectively. This was the result of reduced leaf area (limited source) and an altered vascular bundle in the ear peduncles (limited assimilate flow). The reduced vascular bundle number, rather than the ear peduncle cross-sectional area, significantly affected the final kernel weight when exposed to a water deficit prior to the silking stage. The water deficits prior to and close to the flowering stage significantly reduced ear kernel number; that is, 14 and 19% less during V13-T and R1-2, respectively, compared with the kernel number during the CK treatment. This reflects a smaller sink under water deficit conditions. Additionally, ovary size was reduced the most in the V13-T water deficit compared with other treatments. After rewatering, the water deficit before or during flowering stage continued to have residual effects on grain-filling in the late growth period. The grain-filling rate decreased under the V9-12 water deficit; the grain-filling duration shortened under the R1-2 water deficit; and both negative effects occurred under the V13-T water deficit. This study clearly indicated that (1) the water deficit during the vegetative organ rapid growth period both limited leaf source development and assimilate flow and slowed down kernel development, and (2) the water deficit just before and during flowering reduced kernel sink. Deficits at both times could retard grain-filling and reduce maize yield. The results of the present study might guide irrigation practices in irrigated maize or inform the management of sowing time in rainfed maize, to desynchronize the water deficit and the plant's reactions to such deficits at different stages.

A retrospective analysis of the physiological basis of genetic yield improvement may provide an understanding of yield potential and may indicate avenues for future yield improvement. Rate of yield improvement of maize (Zea mays L.) hybrids in Ontario, Canada has been ≈1.5% yr−1 during the last five decades. Comparison of short‐season hybrids representing yield improvement from the late 1950s to the late 1980s showed that genetic yield improvement was 2.5% per year and that most of the genetic yield improvement could be attributed to increased stress tolerance. Differences in stress tolerance between older and more recent hybrids have been shown for high plant population density, weed interference, low night temperatures during the grain‐filling period, low soil moisture, low soil N, and a number of herbicides. Yield improvement is the result of more efficient capture and use of resources, and the improved efficiency in resource capture and use of newer hybrids is frequently only evident under stress. Improved resource capture has resulted from increased interception of seasonal incident radiation and greater uptake of nutrients and water. The improved resource capture is associated with increased leaf longevity, a more active root system, and a higher ratio of assimilate supply by the leaf canopy (source) and assimilate demand by the grain (sink) during the grain‐filling period. Improvements of resource use under optimum conditions have been small, as leaf photosynthesis, leaf‐angle distribution of the canopy, grain chemical composition, and the proportion of dry matter allocated to the grain at maturity (i.e., harvest index) have remained virtually constant. Genetic improvement of maize has been accompanied by a decrease in plant‐to‐plant variability. Results of our studies indicate that increased stress tolerance is associated with lower plant‐to‐plant variability and that increased plant‐to‐plant variability results in lower stress tolerance.

花期前后干旱是影响黄淮海地区夏玉米产量下降的重要因素之一。于2020—2021年开展池栽控制性试验, 以中科玉505为试验材料, 在开花前后28 d内设置4个水分梯度, 包括100%作物蒸散量ET_C (CK)、70% ET_C (干旱胁迫WD1)、40% ET_C (WD2)和0 ET_C (WD3), 研究花期前后干旱胁迫对夏玉米复水后的光合特性、干物质积累与分配以及产量的影响。结果表明: 干旱胁迫处理复水后夏玉米光合性能没有恢复, 表现为叶片SPAD值、净光合速率和群体叶面积指数、光合势、净同化速率低于对照, 植株干物质积累因此受阻, 导致籽粒库容能力下降。干旱胁迫处理使开花吐丝间隔期延长1~3 d, 籽粒败育率增加, 行粒数和百粒重降低, 尤其是WD3的败育率在2020—2021年分别显著增加220.71%和100.73%, WD1、WD2和WD3的产量在2020—2021年分别减产14.52%、36.69%、39.83%和19.62%、45.18%、54.42%。综上所述, 花期前后干旱胁迫在复水后, 玉米的光合性能仍受到抑制, 进而影响光合同化物的积累与分配, 最终导致库容量和产量显著下降。

Increasing planting density is an effective strategy for improving maize productivity, but grain yield does not increase linearly with the increase in plant density, especially in semiarid environments. However, how planting density regulates the integrated utilization of key input resources (i.e., radiation, water, and nutrients) to affect maize production is not clear. To evaluate the effects of planting density and cultivar on maize canopy structure, photosynthetic characteristics, yield, and resource use efficiency, we conducted a successive field experiment from 2013 to 2018 in Heyang County (Shaanxi Province, China) using three different cultivars [i.e., Yuyu22 (C1), Zhengdan958 (C2), and Xianyu335 (C3)] at four planting densities [i.e., 52,500 (D1), 67,500 (D2), 82,500 (D3), and 97,500 (D4) plants ha–1]. Increasing planting density significantly increased the leaf area index (LAI) and the amount of intercepted photosynthetically active radiation (IPAR), thereby promoting plant growth and crop productivity. However, increased planting density reduced plant photosynthetic capacity [net photosynthetic rate (Pn)], stomatal conductance (Gc), and leaf chlorophyll content. These alterations constitute key mechanisms underlying the decline in crop productivity and yield stability at high planting density. Although improved planting density increased IPAR, it did not promote higher resource use efficiency. Compared with the D1 treatment, the grain yield, precipitation use efficiency (PUE), radiation use efficiency (RUE), and nitrogen use efficiency (NUE) increased by 5.6–12.5%, 2.8–7.1%, and −2.1 to 1.6% in D2, D3, and D4 treatments, respectively. These showed that pursuing too high planting density is not a desirable strategy in the rainfed farming system of semiarid environments. In addition, density-tolerant cultivars (C2 and C3) showed better canopy structure and photosynthetic capacity and recorded higher yield stability and resource use efficiency. Together, these results suggest that growing density-tolerant cultivars at moderate planting density could serve as a promising approach for stabilizing grain yield and realizing the sustainable development of agriculture in semiarid regions.

Concurrent to yield, maize (Zea Mays L.) plant density has significantly increased over the years. Unlike yield, however, the rate of change in plant density and its contribution to maize yield gain are rarely reported. The main objectives of this study were to examine the trend in the agronomic optimum plant density (AOPD) and quantify the contribution of plant density to yield gain. Maize hybrid by seeding rate trials were conducted from 1987-2016 across North America (187,662 data points). Mixed model, response surface, and simple linear regression analyses were applied on the meta-data. New outcomes from this analysis are: (i) an increase in the AOPD at rate of 700 plant ha(-1) yr(-1), (ii) increase in the AOPD of 1386, 580 and 404 plants ha(-1) yr(-1) for very high yielding (VHY, > 13 Mg ha(-1)), high yielding (HY, 10(-13) Mg ha(-1)) and medium yielding (MY, 7-10 Mg ha(-1)), respectively, with a lack of change for the low yielding (LY, < 7 Mg ha(-1)) environment; (iii) plant density contribution to maize yield gain ranged from 8.5% to 17%, and (iv) yield improvement was partially explained by changes in the AOPD but we also identified positive impacts on yield components as other sources for yield gain.

为明确协同提高冬小麦产量和水分利用效率的适宜灌水量和种植密度,选用大穗型品种‘泰农18’(T18)和中穗型品种‘山农22’(S22)为试验材料,设置4个灌溉水平(不灌水、每次灌水45、60、75 mm)和4个种植密度,其中泰农18选用135×104、270×104、405×104、540×104 株·hm-2,山农22选用90×104、180×104、270×104、360×104株·hm-2,研究了籽粒产量、麦田耗水特性和水分利用效率对灌水量和密度互作效应的响应。结果表明: 籽粒产量、总耗水量、土壤贮水消耗量和水分利用效率均受到灌溉水平、种植密度及两者互作效应的显著影响。每次灌水量为45 mm,泰农18种植密度为405×104株·hm-2、山农22种植密度为270×104株·hm-2时,两品种籽粒产量均达到最高,拔节后棵间蒸发量占阶段农田总耗水量的比例最小,1 m以下土壤水消耗比例、水分利用效率高。种植密度与灌溉量合理组合,有利于降低水分无效损耗,提高水分利用效率。

为探究节水灌溉以及品种类型对再生稻产量和稻米品质的影响, 2023年在湖北蕲春和浠水开展大田试验。以3个节水抗旱稻品种(旱优8200、旱优116和旱优73)和3个优质稻品种(箴两优郢香丝苗、荃优粤农丝苗和荃优607)为供试材料, 以湖北省再生稻大面积种植的普通水稻品种(两优6326)为对照, 设置常规灌溉和节水灌溉2种水分管理方式, 分析再生稻模式下不同品种产量和稻米品质对水分管理的响应差异。结果表明, 相较于常规灌溉, 节水灌溉处理使头季和再生季灌水量分别平均减少76%和85%, 但产量和稻米的加工、外观和蒸煮食味品质在水分处理间无显著差异, 且这一结果在不同试验地点间保持一致。这表明, 与常规灌溉相比, 节水抗旱稻和优质稻品种在节水灌溉条件下均能保持较为稳定的头季和再生季产量和稻米品质。优质稻头季和再生季产量分别为8.54 t hm-2和5.88 t hm-2, 相较于普通水稻产量差异不显著; 但头季和再生季整精米率分别显著提高13.5个百分点和20.6个百分点, 垩白粒率和垩白度分别显著降低22.6个百分点和6.4个百分点、10.8个百分点和1.8个百分点。节水抗旱稻在头季的产量以及稻米加工、外观和蒸煮食味品质方面与普通水稻无显著差异, 但在再生季, 产量显著下降17%, 整精米率显著提高17.0个百分点, 垩白粒率和垩白度分别降低5.5个百分点和1.0个百分点。在同一品种类型中, 再生稻产量和稻米品质存在显著的品种间差异。相关性分析表明, 再生季稻米的加工、外观和蒸煮食味品质指标均与头季相应指标呈正相关。因此, 在降水条件较好的地区, 结合优良水稻品种, 实施“以雨养为主、关键生育期适时灌溉”的节水灌溉策略, 可有效降低水分消耗、提升水分利用效率, 同时实现再生稻的高产与优质目标。