种植密度对棉花分离世代产量性状表现及育种选择的影响

通过裂区设计对Ｆ２代４个群体在三种密度下表现进行了研究，子棉产量、皮棉产量在不同密度、不同群体间存在显著差异；Ｆ２代群体与密度间存在互作，不同群体要求的适宜密度不同。Ｆ２代群体间单株结铃数差异显著，单株结铃数在不同密度差异显著，随密度增加单株结铃数减少，但小区总结铃数呈增加趋势；密度与群体间存在互作，密度的大小对４个Ｆ２群体的单株结铃数影响程度不同。Ｆ２代４个群体间衣分差异显著，但单铃重、衣分在不同密度下差异不显著，且互作不显著。种植密度对不同群体的育种选择具有较大影响。     

插秧密度对寒地粳稻的产量及产量构成因素的影响

以松粳6号和超级稻松粳9号两个寒地粳稻品种为试验材料,研究了不同插秧密度对寒地粳稻产量及产量构成因素的影响.结果表明,不同插秧密度对两品种千粒重影响相对较小,而对每穴穗数和每穗粒数的影响相对较大.在黑龙江省第一积温带地区,松粳6号和超级稻松粳9号的最适插秧行株距为30cm×13.3cm和30cm×16.7cm.     

不同生态区种植密度对大豆产量及产量构成的影响

为探索大豆品种的适应生态区及配套高产栽培技术以挖掘品种高产潜力,以中黄35为试验材料,设置不同生态区与种植密度两种处理,研究不同生态区种植密度对大豆产量及产量构成的影响。结果表明,种植密度与生态区对大豆产量及产量构成的影响均达到显著水平,种植密度对产量的影响达到极显著水平,公主岭地区、廊坊地区和新乡地区适宜的种植密度分别达到188750株/hm²、200000株/hm²和177000株/hm²时产量最高。比较不同生态区气候条件,河北廊坊地区因具有较高的日均气温和充足的降雨量,是大豆中黄35高产的适宜生态区。筛选出了不同生态区大豆中黄35的适宜种植密度,构建了高产群体结构,通过对产量构成的显著性分析、相关性分析与通径分析得出,生育期内活动积温高、日均气温在20~26℃范围内的天数多、鼓粒期降雨量充足和种植密度合理是优化大豆群体结构、提高大豆产量的重要途径。     

施肥和密度对杂交粳稻产量构成的影响

运用裂区试验方法，研究了施肥和密度对杂交粳稻产量、产量构成及其群体质量的影响，明确了杂交粳稻高产（≥9.75t/hm^2）栽培的适宜施肥量和栽插密度分别为纯N225～262.5kg/hm^2、栽插密度33.3～37.5万穴/hm^2。     

供钾水平对棉花产量构成及其与产量相关性的影响

采用34个棉花材料,于2007-2008年在田间条件下研究供钾水平对棉花产量及其构成因素和二者之间相关关系的影响.结果表明,施钾可显著提高棉花产量,在气候条件不利的2008年表现更为明显;铃数受供钾水平的影响最大,其次为铃重,衣分受影响最小.偏相关分析和通径分析结果表明,缺钾条件下衣分与产量的关系相对密切,而供钾水平对...     

种植密度和植物生长调节剂对小麦衰老及产量构成的影响

在不同种植密度条件下，以半冬性小麦豫麦49为试验材料，研究了叶面喷施GA3、PP333、6—BA对旗叶衰老过程中MDA合量及小麦产量构成的影响。结果表明：低密度处理有效地减缓了旗叶衰老，提高了千粒重和穗粒数；植物生长调节剂以不同的方式调节小麦旗叶的衰老，影响小麦产量性状，其中PP333和6—BA能较好地协调产量构成因素间的关系，提高作物产量，GA3增产效果不明显。在高密度处理中，PP333能改善产量性状。从总体效果看，基本苗105万／hm^2与PP333相结合为较为适宜的处理组合。     

不同免耕密度对黔油17号产量及产量构成因素的影响

通过对优质杂交油菜品种黔油17号不同免耕栽培密度单因子试验的研究，主要探索黔油17号在贵州油菜主产区遵义推广稻田免耕种植的最佳适宜密度。研究结果表明：在遵义稻田免耕移栽条件下，黔油17号移栽密度在6000-8000株／667m^2范围内，个体发育与群体生长协调统一，综合性状良好，有效分枝数及有效角果数较多，可获得230kg／667m^2以上的较高产量水平；其中，黔油17号在遵义稻田免耕移栽的最佳密度为7000株／667m^2左右，在该密度下可获得278．29kg／667m^2的高产水平。     

根间作用与密度协同作用对小麦间作玉米产量及产量构成的影响

密植是间作模式下重要的增产增效技术措施,本研究旨在探讨间作适应密植的产量构成响应机制。2014—2015年连续两年在河西绿洲灌区进行田间试验,设计不隔根、尼龙网隔根(阻断根系交叉,仅有水分养分的交流)和塑料布隔根(完全阻断)3种根间作用方式,及2个玉米种植密度(9.0万株hm~(-2)和10.5万株hm~(-2)),测定地上、地下部互作对小麦间作玉米产量及产量构成因素的影响。与单作相比,地上、地下部完全作用时间作优势提高48.3%,密度增加使其间作优势增加9.7%,地下部互作对间作优势的贡献率为21.0%,增加密度使其贡献率提高5.0%,根系交叉叠加对间作优势产生的补偿效应为9.0%,地下部水养分交流互补效应为11.1%。地上、地下部完全互作下混合籽粒产量相对于单作增幅最大,高、低密度下增幅分别达58.8%~62.2%和36.1%~36.8%;间作中地下部分对小麦组分籽粒产量的贡献率为26.5%~31.5%,其中根系穿叉产生的补偿效应为12.9%~13.2%,地下部水分养分交流互补效应为12.2%~16.0%;地下互作对玉米组分籽粒产量的贡献率为9.7%~22.6%,增加密度使地下互作贡献率提高7.0%~11.0%;密度提高对不隔根和尼龙网隔根产量的贡献率分别18.1%~23.3%和12.5%~21.5%,说明根间完全作用有利于密度正效应的发挥。地下互作对小麦穗数贡献率为5.5%~11.4%,密度对小麦地下部贡献率影响差异不显著,地下互作对玉米穗数的贡献率为12.5%~16.3%,增加密度使地下互作贡献率增加3.6%~14.1%。通径分析进一步表明,不同根间作用及密植效应下间作小麦、玉米主要通过提高单位面积穗数来提高籽粒产量。本研究表明,增加密度可显著增加间作优势和地下部贡献率,地上地下完全互作有利于密植效应充分发挥,可为进一步发掘密植条件下的间作优势机理提供理论依据。     

陆地棉基因型间竞争对产量及构成因素的影响

利用陆地棉色素腺体作为指示性状，采用４个遗传差异较大的品种研究了在基因型竞争条件下陆地棉植株性状的变化。结果表明，纯型种植时高产的基因型，在品种混合体中不同基因型竞争下生产力下降，而低产基因型的生产力则有所提高。品种产量越高，由其组成的混合体比预期值减产越多。品种混合体的产量均未超过其组成中的高产品种，多数品种混合体的产量均低于预期值。籽棉产量、皮棉产量、单株结铃数均具有明显的竞争效应和趋势，单铃重、衣分无明显的竞争趋势。     

棉花产量组分的改良对产量的影响

采用1973～1996年黄淮棉区棉花品种区域试验的历史资料来研究我国黄淮棉区棉花品种产量组分的改良对产量的影响。结果表明,产量从750kg·hm     

缩节胺(DPC)对不同密度下棉花冠层结构特征与产量性状的影响

在新疆气候生态条件下,设置适量化调和超量化调方式,每个化调下设3个种植密度,研究了化学调节剂(DPC)对不同密度棉花冠层结构及产量的影响.结果表明:随密度增加,两种化调量下均表现叶面积指数(LAI)增大、叶倾角(MFA)变大,株型变紧凑;但密度过大,群体散射辐射透过系数(TR)小,造成生育后期群体光合速率(CAP)较快...     

新疆机采模式下棉花株行距配置对冠层结构指标及产量的影响

【目的】为了研究不同株行距配置对机采棉花冠层结构指标及产量的影响。【方法】在田间条件下,选用棉花杂交种鲁棉研24号和常规品种新陆早60号为供试材料,设置适宜机采的1膜3行等行距(76 cm+76cm+76 cm)低密度、1膜6行宽窄行(66 cm+10 cm)高密度及1膜3行等行距(76 cm+76 cm+76 cm)双株高密度3种配置方式进行试验。【结果】等行距低密度下,棉花生育前期生长旺盛,叶面积指数与光吸收率迅速增加至最高值;生育后期,叶面积指数及光吸收率下降幅度分别为10.4%~13.6%、3.7%~4.2%,低于其他两种处理,且干物质积累量较高。等行距低密度下杂交棉产量最高。【结论】等行距低密度下杂交棉实现高产的生理基础主要是:生育前期叶面积指数及光吸收率增长迅速,干物质积累较快;生育后期叶面积指数及光吸收率下降缓慢,能维持较高水平,光合生产能力较高,干物质积累量最大。     

Effects of Genotypes and Plant Density on Yield, Yield Components and Photosynthesis in Bt Transgenic Cotton

Bt (Bacillus thuringiensis) transgenic cotton (Gossypium hirsutum L.), including the introduced, indigenous Chinese non‐hybrid and hybrid cotton, is spreading very rapidly in China. Agronomic and photosynthetic performance as well as the optimum plant density for planting Bt cotton may vary with genotypes. With three types of commercial Bt cotton varieties, two field experiments were conducted to study yield performance and leaf photosynthetic rate (Pn) during 2000 and 2001, and yield interaction between variety and plant density during 2001 and 2002 in Yellow River region in northern China. The first experiment showed that the indigenous Chinese Bt cotton significantly differed from the introduced Bt cotton (IBtC) in plant growth and yield components. As a result of manipulation of boll numbers, boll weight and lint percentage, there was no significant difference in lint yield between Chinese non‐hybrid Bt cotton (CBtC) and the IBtC, but two Chinese hybrid Bt cotton (HBtC) varieties exhibited significantly higher lint yield than all other varieties in either 2000 or 2001. Hybrid cotton SCRC15 showed a one‐peak curvilinear change in diurnal course of Pn throughout the growing season, while non‐hybrid cotton 33B and SCRC16 exhibited severe mid‐day depression in Pn in squaring, flowering or boll‐setting stage. The second experiment showed that the main effect of plant population on lint yield was not significant, and yield difference among all treatments was derived from varieties and the interaction between plant density and variety. The optimal plant densities in terms of lint yield for the introduced, indigenous CBtC and HBtC genotypes were 6.0, 4.5 and 3.0 plants m^?2 respectively.     

Planting Time and Seed Density Effects on Potato in Subtropical China

Planting times of potato in subtropical China vary and are often not optimal; their effects were studied in association with those of plant density. The research programme included 10 trials at three elevations (500, 750, 1200 m asl) in the spring and autumn seasons of 2 years with several contrasting varieties and different seed origins. Earlier planting in spring increased yield at 500 m asl. This effect was associated with better light use efficiency, higher rates of photosynthesis and more tubers per plant. At 750 m asl the effects of planting time in spring were the opposite: later planting increased yield. At 1200 m asl effects on yield were absent. Effects of planting time in autumn on yield were generally absent at all elevations, although plant stands at early planting were consistently and often severely reduced. Denser planting produced yields that were higher per unit area because of larger accumulated canopy cover but were lower per plant. Higher density consistently reduced plant stand. Density did not interact with planting time, not even in those experiments in which planting time also affected plant stands.
Optimal planting time depended on the amount of rainfall prior to planting especially in the autumn season, but also on cultivar and dormancy of the seed tubers used. The earlier variety yielded more than the later variety at low elevation, whereas the later variety yielded more at higher elevation. It is necessary to use cultivars that tuberize early to make better use of the limited growing period at lower elevation. The large variation of dormancy that affects plant growth and yield is caused primarily by differences in accumulated temperature sum (as affected by planting time, elevation of growth and storage, and season), genetics (variety), and their interaction with cultivation techniques.     

Effects of Planting Density and Chemical control on Yield and Mineral Elements Accumulation of Cotton Direct-Seeded after Wheat

[Objective] The effects of planting density and Miantaijin treatment on yield and nitrogen, phosphorus and potassium uptake and accumulation in cotton direct-seeded after wheat in the Yangtze River basin were studied in order to clarify the high-yield cultivation techniques under this cropping system. 【Method】 In 2011 and 2012, Guoxinzao 11-1 at the experimental material, and adopted three densities (75 000, 90 000 and 105 000 plants·hm^－2) and three Miantaijin doses (0 mL·hm^－2, 1 170 mL·hm^－2 and 2 340 mL·hm^－2). 【Result】 The results showed that the highest yield was 3 551.3～3 687.5 kg·hm^－2 under 90 000～105 000 plant·hm^－2 density combined with 1 170 mL·hm^－2 Miantaijin (seedling stage: 90 mL·hm^－2, peak squaring stage: 180 mL·hm^－2, peak flowering stage: 360 mL·hm^－2, peak boll-setting stage: 540 mL·hm^－2). Under these conditions, the highest uptake of nitrogen, phosphorus and potassium was 117.8 kg·hm^－2, 77.4 kg·hm^－2, 116.4 kg·hm^－2, respectively. Among them, nitrogen uptake was the highest in the peak-squaring stage to peak-flowering stage, while the highest phosphorus and potassium uptake were both detected in the peak-flowering to boll-opening stage. The correlation analysis showed that there was a significant linear positive correlation between the yield of direct seeded cotton after wheat and the total absorption and accumulation of nitrogen, phosphorus and potassium, especially during the peak flowering to boll-opening stage. 【Conclusion】 The suitable application dose of Miantaijin under medium and high density could enhance the absorption of nitrogen, phosphorus and potassium in the whole growth period of cotton, especially in the peak flowering to boll-opening stage. and thus result in the high yield of direct-seeded cotton after wheat in the Yangtze River basin.     

Effects of Planting Date on Sucrose Metabolism in the Leaf Subtending to Cotton Boll,Within-boll Yield Components and Fiber Quality

[Objective] The present study aimed to investigate how sucrose metabolism in the leaf subtending to cotton boll, within-boll yield components and fiber quality respond to varying planting dates. [Method] Two upland cotton lines A705 and A201 differing in cotton boll traits were field tested in 2016-2017. Two different planting dates were designed with early planting on April 12, 2016, and April 15, 2017, and late planting on May 6, 2016, and May 28, 2017, respectively. Dynamics of non-structural carbohydrates (sucrose, hexose, starch) and key sucrose metabolism enzymes in the leaf subtending to cotton boll were examined including vacuolar acid invertase, cell wall acid invertase, sucrose phosphate synthase and sucrose synthase. The differences between two planting dates were compared for within- boll yield components, fiber quality and sucrose metabolism related characteristics. [Result] Late planting lengthened the period of cotton boll maturation relative to early planting. Boll weight, seed mass per boll, seed index and fiber length were increased, and lint percentage and micronaire were decreased. Late planting reduced the activities of cell wall acid invertase and sucrose synthase responsible for sucrose degradation, and in turn led to the increment of sucrose concentration in the subtending leaves which might enhance the carbon supply to the opposite bolls. [Conclusion] Lower temperature due to late planting could contribute to the more full development of cotton bolls. Late planting is an alternative consideration in improvement of fiber quality in cotton cultural practices.     

棉花单一群体创“150”产量构成及其贡献率分析

单位面积铃数、单铃重和衣分是构成棉花产量的三个重要因素。单位面积铃数对创“１５０”（公顷２２５０ｋｇ,后同）产量的贡献率最大,单铃重和衣分次之。偏相关分析表明,单位面积铃数与单铃重和衣分呈极显著的负相关。增加单位面积铃数与提高单铃重和衣分是创“１５０”高产的不同主攻方向。主攻单位面积铃数时,实收密度不得低于４．６５万株·ｈｍ－２。选用高铃重高衣分优良品种,创高产的风险性较小。创高产群体要求生物学产量稳定在１５ｔ·ｈｍ－２以上,子棉经济系数稳定在０．３８３以上。     

密度及行距配置对‘丰油10号’生长发育、产量和品质的影响

为了探究‘丰油10号’在黄淮地区适宜的播种密度与行距配置。在河南省油菜主产区进行大田试验,比较不同种植密度及行距配置方式下,‘丰油10号’的物候期、叶片叶色值(specialty products agricultural division, SPAD)及开花期叶面积指数(leaf area index, LAI)、经济性状、产量和品质情况。结果表明：‘丰油10号’的生育期随着密度和行距的增大,逐渐缩短;叶片的SPAD值在蕾薹期和开花期随密度增大逐渐降低,随行距缩小而减小;植株LAI在开花期随着密度的增大先增后减,同一密度下,40 cm行距下较高;株高、一次有效分枝数、主花序的长度和角果数随密度的增加逐渐较小,分枝部位则升高,随行距的减小单株有效角果数下降,千粒重不受密度和行距配置的影响;籽粒产量和含油量随着种植密度的增加先增后减,籽粒产量在种植密度为42万株/hm²,40 cm行距下最高,为2734.6 kg/hm²,当行距缩小到20 cm,籽粒平均减产4.65%;籽粒芥酸和硫苷含量不随密度和行距改变发生变化。在其它栽培措施保持不变的情况下,建议‘丰油10号’在黄淮流域的种植密度控制在34.5万~49.5万株/hm²,行距设置为40 cm。     

种植密度对东北特早熟棉区棉花生物量和氮素累积的影响

 以辽棉19号（生育期125 d）和新棉33B（生育期135 d）2个生育期差异较大的品种为材料,于2007－2008年在东北特早熟棉区（辽宁辽阳,41°26' N,123°14' E）设置棉花种植密度试验（7.50万、9.75万、12.00 万株·hm^-2）,研究不同棉花群体生物量与氮素动态累积特征的差异及其与产量品质形成的关系。结果表明,棉花群体生物量和氮素累积动态随生育进程的变化符合“S”型曲线,棉花群体生物量和氮素存在异速累积现象,氮素累积快速起始期及终止期均较生物量累积提前10 d左右。2品种均以9.75 万株·hm^-2密度下棉花生物量、氮素动态累积过程最为优化,皮棉产量最高,纤维品质最优;密度过高尽管群体生物量、氮素累积量较高,但经济产量下降。