不同株型玉米杂交种产量构成因素及其相关分析

利用方差分析、F测验以及相关分析的统计学方法，对试验调查结果和室内考种结果进行统计学分析，研究了在一定的耕作和栽培水平条件下，四种不同株型玉米杂交种产量差异显著性和相关性。结果表明，不同株型玉米杂交种产量差异显著．各种株型玉米杂交种产量与叶向值均不呈相关性，紧凑型玉米杂交种产量与单位叶面积产量、穗长、单株生产力、单位叶面积籽粒产量、百粒重呈明显正相关，并且相关显著。通过紧凑型和平展型玉米杂交种群体冠层结构的分析，证明紧凑型玉米杂交种群体冠层结构较为理想，试验结果表明，在我省现有的耕作和栽培水平条件下，可以大面积种植紧凑型玉米杂交种．     

不同株型玉米叶片形态结构的研究

紧凑型玉米与平展型玉米叶片形态结构有一定差别。主要表现在紧凑型玉米叶表皮气孔数目多于平展型。上表皮多17.0%，下表皮多11.5%。紧凑型玉米叶片上、下表皮气孔密度差别比平展型小。紧凑型玉米下表皮比上表皮气孔多44%，而平展型多50%。两种株型玉米叶片维管束鞘中的叶绿体均位于细胞外方，呈半圆形排列。紧凑型玉米比平展型玉米叶片维管束鞘中叶绿体含量较多。两种株型玉米叶片中脉有一定差异，紧凑型玉米叶片中脉较宽且向叶正面凹陷较深。     

不同株型玉米杂交种的产量及农艺性状的研究

作者分析研究了目前山东省3种不同株型玉米杂交种的主要农艺性状,认为紧凑型玉米杂交种的产量最高,中间型玉米杂交种次之,平展型玉米杂交种的产量最低。紧凑型玉米杂交种高产的主要原因是由于增大密度使总粒数增多。因此,今后应大力选育和推广紧凑型玉米杂交种,以提高玉米产量。     

育种与栽培相结合紧凑型玉米创高产

从探索我国玉米高产道路进行夏玉米高产攻关研究开始,回顾了育种与栽培相结合培创玉米高产的研究过程。并通过紧凑型玉米与平展型玉米的株型比较试验,总结出紧凑型玉米杂交种的生理特征,证明了紧凑型玉米较平展型玉米的增产作用大,创造出16444.35kg/hm2的夏玉米高产纪录,推动了我国紧凑型玉米育种与高产栽培研究事业的发展。     

紧凑型玉米高产生理基础及高产栽培

紧凑型玉米与平展型玉米相比，具有稳上部叶夹角小、株型紧凑、耐密植、叶向值大、叶面积系数大、光合势高、净光合产物多、群体库容量大、经济系数高的特点，这是紧凑型玉米高产的重要生理基础。改进制种技术，争取制种高产稳产）是紧凑型玉米推广应用重要的种质基础。紧凑型玉米高产栽培，必须充分发挥其耐密性特点，适当增加种植密度，扩大群体库容量，加强田间管理，延长功能叶的有效期，增强源的供应能力。     

玉米株型对大豆氮素积累、转运和籽粒蛋白质产量的影响

以“玉/豆”套作模式为背景,三个不同株型的玉米和三个不同熟期的大豆材料,采用两因素裂区设计,研究了大豆地上部氮素积累和转运,以及籽粒蛋白质的差异。结果表明,各大豆品种中,以晚熟大豆在不同时期、不同器官的氮素积累量为最高,分别高出中、早熟品种 121.09%和165.33%,其氮素积累速率、有效荚数、籽粒产量和蛋白质含量平均分别为3.78kg/hm2/d、60.27荚、3 840.22kg/hm2和48.71 %,均显著高于中、早熟品种;大豆地上部氮素积累总量、积累速率、转运量和单株有效荚数均随着玉米株型的变化（从紧凑型到平展型）而减少,紧凑型玉米下的大豆籽粒产量和蛋白质产量分别为2 609.10kg/hm2和1 203.83kg/hm2,显著高于其他玉米株型处理;交互作用分析表明,玉米株型与大豆熟性在单株荚数、单荚粒数、籽粒产量和蛋白质产量上互作显著;相关性分析表明蛋白质产量与籽粒产量极显著相关。因此,选择紧凑型玉米与晚熟大豆品种搭配有利于提高套作大豆的产量,从而提高籽粒蛋白质产量。     

不同株型玉米套作大豆生长环境动态及群体产量研究

为探明玉米-大豆带状套作下大豆生长环境动态规律及产量变化,选用不同株型玉米品种与大豆带状套作,分析了光强,光质,空气、土壤温湿度及产量变化规律。结果表明:大豆与紧凑型玉米套作下其冠层光合有效辐射和光谱辐照度在不同高度和不同时间都高于半紧凑和松散型。玉米-大豆带状套作群体土壤水分含量从大豆行间到玉米窄行间逐渐降低,大豆与紧凑型玉米套作群体不同空间位置土壤含水量变化幅度较小,而半紧凑和松散型玉米变化幅度较大。对于空气温湿度,紧凑型玉米套作下的大豆冠层空气温度最高,湿度最低。此外,大豆与紧凑型玉米套作下不同空间位置土壤0~10 cm温度高于半紧凑和松散型套作。大豆与紧凑型玉米套作下其产量显著高于与半紧凑和松散型玉米套作,但紧凑型玉米产量最低。因此,在玉米-大豆带状套作群体不同配置相关研究中应当考虑玉米株型对大豆生长环境及产量的影响。     

华北地区夏玉米理想株型研究

以紧凑型玉米品种郑单958为材料,使用金得乐(EC)化控试剂,在不同密度条件下对紧凑型玉米的群体结构进一步优化,以挖掘夏玉米的增产潜力。试验设3个密度,每个密度设4个EC试剂叶面喷施处理,不喷施为对照(CK)。结果表明,不同化控处理下,6叶展期叶面喷施EC试剂2.25 mL/L与对照差异不明显;6叶展期喷施2.25mL/L、12叶展期喷施1.5 mL/L夏玉米株高、穗位高降低,叶茎夹角增大,穗位层叶间距缩小,株型趋向平展型;6、8叶展期分别叶面喷施1.5 mL/L夏玉米株高降低不明显,穗位高降低,单株叶面积、叶茎夹角缩小,株型更为紧凑。分析结果表明,在高密度条件下调整株型是解决群体结构郁闭突破点,确认整体紧凑、穗位低、穗下层叶间距小、穗位层及穗上层叶茎夹角小、叶间距大、群体结构持续时间长为理想株型。     

玉米几个自交系组配高产紧凑型杂交种的研究

以近年育成的部分玉米新自交系和骨干系为材料,采用不完全双列杂交设计,对其主要株型和产量性状进行了遗传研究。结果表明,10078、32和152能明显降低株高、穗位高和叶夹角,改善F₁的株型结构,可用来组配紧凑型杂交种。698-3和200B既能改善F₁的株型,还能改进F₁的部分产量结构,用其作亲本有利组配出高产紧凑型杂交种。新选系7613和273能显著改进F₁的产量结构,其产量配合力显著高于平均效应,属于高配合力自交系,用其作亲本易配出高产杂交种,但其株型要视另一亲本的株型而定。     

四川省常用玉米自交系“棒三叶”农艺性状聚类分析

根据玉米棒三叶的6个农艺性状对四川省常用自交系进行了聚类分析。结果表明,四川省常用玉米自交系中有许多优异资源,但以棒三叶呈较宽叶片、较大面积、较紧凑型和较大叶面积、低叶绿素含量中间型为主,未出现较长叶片、较大叶面积、较紧凑型和较大叶面积、高叶绿素含量、较紧凑型。说明在理想株型育种中,还需进一步挖掘玉米基因资源,在考虑配合力遗传的同时加强基因重组,培育不断接近理想株型的优异玉米自交系资源。     

Simulating the effects of chemical and non-chemical fertilization practices on carbon sequestration and nitrogen loss in subtropical paddy soils using the DNDC model

Understanding the long-term and quantitative effects of different fertilization practices on carbon sequestration and nitrogen loss is important when establishing the best fertilization regime. In this study, the DeNitrification–DeComposition (DNDC) model was validated first for the change of soil organic carbon (SOC) at the site mode and at the regional mode, and then it was used to simulate the effects of three fertilization practices including rice straw (RS) returning, chemical fertilizer application (CF), and green manure planting (GM) on C and N dynamics in paddy soils from a subtropical area of China. The prevailing fertilization practices in the study area were set as the baseline scenario, and alternative scenarios were assigned by varying only one of the three fertilization practices. All three fertilization practices increased SOC content but had different effects on rice yield, N₂O emission, and nitrate leaching loss. Compared with a baseline RS rate of 15 %, the SOC contents less than RS rates of 30, 50, and 80 % were increased on average by 12.84, 29.48, and 53.50 %, respectively. SOC content also increased as the CF rate rose from 70 to 130 % of the baseline scenario and then leveled off from 130 to 160 %. SOC contents under GM were higher than that without GM by 35.74 %. Both the N₂O emissions and the nitrate leaching were increased with the increasing CF rate, while they decreased under GM treatment. However, RS increased the N₂O emissions but decreased the nitrate leaching. The polygon-based modeling method with the DNDC could accurately evaluate the general trend of SOC dynamics and nitrogen loss from paddy soils.     

我国玉米DNA指纹数据库管理系统的建立

经过3年的开发研究,初步构建了我国玉米DNA指纹数据库管理系统(http://www.maizeDNA.com),该系统具有数据管理、数据浏览和数据分析3部分功能,通过将品种的基本信息、形态数据和图片、DNA指纹数据和指纹图谱等各种数据信息汇总起来,建立强大的联合查询系统。该网站将为国家品种管理工作提供有效的手段。     

大理州29个玉米品种(系)产量比较及主要农艺性状关联度分析

为了解大理州玉米品种主要农艺性状间的关系,进而指导育种实践,本文采用灰色关联度分析方法对大理州29个玉米品种(系)产量及主要农艺性状关联度进行了比较分析。结果表明:9-5、卓玉299、海玉92号的产量较其他玉米品种(系)相对要高;玉米品种(系)的产量与主要农艺性状关联度大小为:百粒质量出籽率行粒数穗粗穗行数穗长秃尖生育期株高穗位;在育种实践中,在着重选择与产量紧密度高的农艺性状的同时,也要协调好各农艺性状间的主次关系。     

Soil Microbial Communities Reflect both Inherent Soil Properties and Management Practices in Wisconsin Potato Fields

Microbial communities in soils provide numerous functions vital to agricultural productivity, and there is growing interest in understanding and manipulating these communities to achieve more sustainable production systems. We investigated microbial communities in potato fields in Wisconsin to determine the extent to which microbial communities were structured by inherent soil properties versus factors under grower control. We found that soil properties, including texture and chemistry, shaped microbial communities at broad levels, determining the diversity and abundance of phyla. Organic versus conventional management, however, correlated with finer scale differences in microbial communities, while crop variety was not associated with microbial community composition in this study. These results suggest that grower practices have the potential to alter microbial communities, but these effects will take place within an existing soil context. Future research is necessary to determine how these patterns in microbial community structure relate to functional outcomes for plant health.     

鄂北双季花生高产栽培技术初探

一年内连续两次种植花生是鄂北地区花生种植方式的一项重要改革。通过三年的试验，研究了在鄂北条件下双季连作花生栽培的良种选用、播种期、种植密度和管理措施等关键栽培技术，结果表明以早熟高产的中花４号等品种，第一季地膜覆盖于３月下旬播种，第二季在８月初露地播种并适当增加种植密度，能够获得双季花生７５００ｋｇ／ｈｍ２以上的产量。     

冬小麦不同品种类型生长动态分析

在一般的生产条件下,对多穗型、均衡型、重穗型三种品种类型的产量构成、茎蘖动态、次生根数量、叶面积和干物质积累进行了研究。结果表明,在一定的生产环境和相应的栽培技术下,三种类型品种都能获得高产。但在目前的生产条件及生产水平下则是以均衡型、多穗型品种较为经济,且易获得高产稳产。     

The effect of storage conditions on subsequent field performance of potato seed tubers in Tunisia

Summary Seed tubers of four cultivars were grown under similar conditions and harvested simulataneously. They were stored in traditional dark storage, diffused-light storage, or cold storage, and with combinations of these three methods for 150 or 230 days beginning in the hot, dry summer period. The effect of storage conditions on emergence, stem and tuber number, tuber size distribution and yield is discussed. Results suggest an optimal combination of storage method, cultivar choice, and sprout management practices may be achieved to obviate the need for cold storage in warm climates. Emergence and yield were consistently good for the 150-day storage period when traditional storage was followed by diffused-light storage. The sam technology gave promising results for the 230-day period with cultivars Claustar or Désirée when seed was desprouted prior to planting.     

Influence of potato cultivars on the effectiveness of fungicide control of early blight

Three potato cultivars differing in degree of susceptibility to early blight were grown under crop management practices typical for Pennsylvania in 1987 and 1988. There were three experimental treatments: no fungicides, mancozeb with weekly applications initiated at 7 or 8 weeks after planting (early treatment), and weekly applications initiated at first symptoms of disease (late treatment). The no-fungicide control treatment had significantly higher AUDPC values than either treatment with fungicides and the no-fungicide treatment had significantly lower yield in 1987 but not in 1988. Tubers from the no-fungicide control had lower specific gravity. Norchip, the cultivar most susceptible to early blight examined in this study, responded the most in yield increases by the increased fungicide applications.     

Long-term evaluation of the BMPs scenarios in reducing nutrient surface loads from paddy rice cultivation in Korea using the CREAMS-PADDY model

Curbing nutrient loads from rice cultivation has been an issue for the water quality management of surface water bodies in the Asian monsoon region. The objectives of this study were to develop paddy BMP scenarios and to evaluate their effectiveness on nutrient loads reduction using long-term model simulation. Totally five BMP scenarios were developed based on the three paddy farming factors of drainage outlet height, fertilizer type, and application amount and were compared with conventional practices. CREAMS-PADDY model was chosen for the paddy nutrient simulation, and two-year field experimental data were used for the model calibration and validation. The validated model was used to evaluate the developed BMP scenarios for the 46 years of simulation period. The observed nutrient loads were 15.2 and 1.45 kg/ha for nitrogen and phosphorus, respectively, and mainly occurred by early season drainage and rainfall runoff in summer. The long-term simulation showed that the soil test-based fertilization and drainage outlet raising practice were the two most effective methods in nutrient loads reduction. The combination of these two resulted in the greatest loads reduction by 29 and 37 % for T-N and T-P, respectively (p value < 0.001). Overall the effectiveness of the BMP scenarios was decreased in the wet season. As the conclusion, outlet height control and soil nutrient-based fertilization were suggested as the effective practices in paddy loads reduction and their combination can be a practicable BMP scenario for the paddy nutrient management.     

Soybean yield physiology and development of high-yielding practices in Northeast China

Soybean (Glycine max (L.) Merrill), one of the most important crops in China, has been known to man for over 5000 years. Soybean production in China increased from 7.5 million Mg in 1978 to 26 million Mg in 2005. The largest production areas in China are in the Northeast China's three provinces, where soybean is spring seeded and grown as a full-season crop. Development of research programs and rapid adoption of technologies emerging from agricultural research by producers including a better understanding of the physiological processes of growth and development, improved cultivars and cultural practices, and a higher demand of the soybean processing industry has contributed much to the upward trend in on-farm yield and total production. Research on leaf area index (LAI), light interception and canopy photosynthesis, source–sink relationships, phytohormones, environmental stresses (drought and cold damage), development of cultivar selection, tillage systems, cultivation practices as well as weeds, insects and diseases during the last half century in Northeast China were reviewed. The intent is to document a summary of the understanding of soybean physiology and culture for high yields mainly from Chinese scientists’ perspective.