玉米雌雄穗发育及其与产量的关系

玉米雌雄穗分化发育具有特殊的规律,而且受到多种因素的影响,穗发育的优劣又决定玉米产量的高低。分析了多种因素对玉米雌雄穗分化发育的影响,指出干旱等逆境对玉米雌雄穗发育及产量有重大作用。简要阐述了开花间隔、种植密度等对产量的影响。     

不同基因型玉米品种抗旱性田间鉴定研究

为研究不同品种玉米在干旱条件下的形态与产量性状、明确不同基因型玉米品种的抗旱性,采用产量抗旱指数为评价参数,分析各性状与参数间的关系,筛选出有效的综合评价指标,并对各品种的抗旱性进行分类。结果表明,干旱处理下玉米品种籽粒产量均明显低于正常处理,雌雄开花间隔增加,株高和穗位高降低,穗短小,秃尖多,穗粒数少,粒质量轻,最终导致产量下降。雌雄开花间隔、保绿性与产量抗旱指数之间呈极显著或显著相关。通过这些形态指标可鉴选出抗旱性好的品种。     

玉米的雌雄穗开花间隔研究进展

在玉米开花期因受环境胁迫会导致果穗生长减缓,雄穗与雌穗的开花间隔加大.此现象称为雌雄穗开花间隔(ASI),或吐丝延迟、同步性丧失、雄性先熟等.在胁迫条件下,玉米的产量与ASI呈显著的正相关.综述了前人在干旱、密植、低氮、及长光胁迫对玉米产量与ASI的影响.ASI的改变可能预示在开花期新形成的同化物在分配上的差异.ASI可作为抗逆玉米种质筛选的主要性状之一.     

耐旱性玉米筛选的形态指标研究

试验以20个CIMMYT选育的耐旱种质DTPWC9的不同株系为材料，对充足灌水、中度水分胁迫和严重水分胁迫几种不同供水条件下植株的一些形态指标与耐旱性的关系进行了研究。结果表明：除子粒产量外，单株穗数、雌雄穗开花间隔、叶片衰老指数及叶片卷曲指数是耐旱性筛选的重要性状指标。研究结果对大田玉米耐旱性筛选具有指导意义。     

耐旱和半多穗型玉米种质对密度的反应

试验于1999－2000年在国际玉米小麦改良中心（CIMMYT）进行，以耐旱种质TS系列及半多穗型种质SPL系列为材料，测度子此二类种质对密度的反应。结果表明，随的增加，群体前期的光截取量增加，株高和穗位高均有增加，下部叶片的衰老时间提前，穗位叶片的叶绿素含量也降低。同时由于高密导致单株发育不良，根、茎倒伏率增加。密度的增加还使玉米的雌雄穗开花间隔延长，单株平均穗数降低，进而影响到玉米的产量，在正常灌溉条件下，半多穗型种质对密度的反应优干耐旱性种质，在干旱条件下筛选出的高世代种质在充足灌水下也表现高产。     

在干旱胁迫条件下玉米雌雄穗开花间隔时间(ASI)与产量关系的研究

干旱胁迫是影响玉米雌雄穗开花间隔时间(ASI)的主要因素之一,对玉米开花期的生殖生长影响较大,导致玉米不能正常授粉,进而影响到玉米产量。本研究在玉米开花期,干旱胁迫条件下对120份玉米自交系进行研究,玉米雌雄穗开花间隔时间(ASI)增大,雌穗生长减缓,吐丝期延迟,雄穗发育不良,花粉量减少。结穗率和籽粒产量严重下降,其中ASI、结穗率与籽粒产量均呈极显著相关。因此,在选择抗旱玉米种质资源时,可利用ASI作为重要的筛选指标之一。     

吐丝前高温胁迫对不同耐热型夏玉米产量及穗发育特征的影响

【目的】吐丝前高温是影响玉米雌雄穗发育的重要因素之一,对玉米产量形成至关重要。探明吐丝前高温胁迫对玉米产量及雌雄穗发育进程的影响,为玉米稳产高产提供保障。【方法】以花粒期耐热型玉米品种郑单958和热敏感型玉米品种联创808为供试材料,采用盆栽试验,在第9片叶展开期至吐丝期,移入人工智能温室进行高温胁迫(最高温度/最低温度为40/30℃),对照的最高温度/最低温度为35/25℃,研究高温胁迫对不同耐热型玉米产量、雌雄穗生长发育及外观形态结构、花粉花丝微观结构和光合特性的影响。【结果】第9片叶展开期至吐丝期高温胁迫显著降低了夏玉米穗长、行粒数、穗粒数和粒重,进而导致产量显著下降。与对照相比,高温胁迫下郑单958和联创808行粒数分别降低22.21%和24.59%,穗粒数分别降低29.85%和27.80%,千粒重分别降低24.04%和17.47%,导致籽粒产量分别降低44.98%和40.88%,差异均达显著水平。高温胁迫抑制了2个玉米品种雌雄穗发育,雌、雄穗干重和雌穗长度显著降低,光合性能显著降低,开花吐丝间隔期(ASI)拉长。高温胁迫后,郑单958和联创808吐丝期雄穗干重分别降低39.4...     

水分亏缺对玉米籽粒形成的影响

在人工控水条件下,研究了不同时期水分亏缺后复水对玉米穗部性状及籽粒形成的影响。结果表明,不同时期水分亏缺对玉米穗行数和穗粗影响不显著,但对玉米秃尖长、瘪粒数、行粒数影响显著;4～9叶期水分亏缺对玉米穗部性状及籽粒形成影响不显著;随着土壤水分亏缺时间的延长,玉米雌雄穗开花间隔延长,花丝伸长速率降低,上部花丝抽出困难,籽粒灌浆速率降低,籽粒败育率显著提高。土壤水分亏缺对玉米穗上部籽粒发育的影响大于对中下部籽粒的影响。     

夏玉米产量结构与种植密度关系研究

以夏玉米品种登海618为试验材料,采用单因素随机区组排列,研究了6个种植密度条件下的玉米产量、穗部性状与种植密度的相关性。结果表明,在天津地区,夏播玉米品种登海618的每亩最佳种植密度约为5 760株。在本试验的种植密度范围内,玉米产量随种植密度的增加而增加,当亩密度达到5 760株后,产量有所下降,产量结构随着种植密度的增加,单位面积收获穗数随之增加,穗粒数先增后减,百粒重随之减少。     

21个常用玉米杂交种的耐旱性研究

筛选具有耐旱、对水分利用经济型的玉米品种是提高产量、避灾减灾、实现农业可持续发展的重要手段.以阜新地区生产上正在使用的21个玉米杂交种为材料,对各品种的籽粒产量、干物量、单株穗数、株高、倒伏系数、雌雄穗开花间隔、叶片卷曲指数、叶片衰老指数等指标进行了综合考察,得出各品种的综合耐旱指数,排出了玉米品种耐旱性的顺序,对农业生产及进一步筛选耐旱玉米种质具有一定指导意义.     

新疆玉米新自交系耐旱性鉴定与评价

采用玉米开花期干旱胁迫法,以籽粒产量为主要性状,结合株高、穗位高、穗长、秃尖长、穗行数、行粒数、穗粒数、ASI值等性状,用种质耐旱性指数(DTIg)作为玉米自交系资源耐旱性鉴定与评价的主要指标,对49份玉米自交系耐旱性做了鉴定与评价。筛选出新自672、新自641、新自636、新自534、新自521、新自635、A14-2、运642等8份干旱胁迫条件下花期协调,耐旱性极强的新玉米自交系。     

Evaluation and Quantitative Inheritance of Several Drought-Relative Traits in Maize

The authors evaluated 57 parental inbred lines of maize hybrids disseminated in Southwest China for drought tolerance under drought-stressed and well-watered conditions. Multiple regression analyses between drought tolerant coefficients of the grain yield per plant and 15 morphological and physiological traits measured from a subset of 12 selected lines, identified traits 1 and 5, which were important for drought tolerance, at the seedling and reproductive stages respectively. Gene effects, combining abilities, and heritabilities of these traits were estimated using generation mean and diallel cross methods. Dominance effect was more important than additive effect for the plant height, anthesis-silking interval （ASI）, root weight, and the grain yield per plant, whereas, they were about equal for the leaf emergence rate. The variances of special combining ability （SCA） were about double that of the general combining ability （GCA） for plant height, ASI and grain yield per plant, although they were about equal for leaf emergence rate and root weight. Narrow sense heritabilities of the five traits for the reproductive stage were not high （12.8-29.6%）, although broad sense heritabilities for plant height, ASI, and grain yield were as high as 70-85%. A segregating population consisting of 183 F2 plants from the cross N87-1 （drought tolerant） × 9526 （susceptible）, was genotyped at 103 SSR loci and the F2：4 families were evaluated under two water regimes. Twelve quantitative trait loci （QTLs） （two for plant height, five for ASI, four for root biomass, and one for grain yield） were identified, most of which had overdominant gene action. Some chromosomal regions, such as those linked to markers umcl051 （bin 4.08）, umc2881 （bin 4.03）, and phi034 （bin 7.02）, had overlapping QTLs.     

干旱胁迫下春玉米冠层吐丝动态及籽粒数模拟研究

【目的】为实现干旱胁迫下玉米冠层吐丝动态的模拟,建立开花—吐丝间隔(anthesis-silking interval,ASI)和吐丝百分率与单位面积籽粒数的关系,改善干旱胁迫条件下玉米籽粒数的模拟效果。【方法】本研究基于锦州农业气象试验站干旱胁迫控制试验,测定了不同水分处理下玉米开花前后植株平均生长速率(PGR)、玉米冠层逐日吐丝百分率动态、ASI、开花后果穗生物量累积和株籽粒数等指标,利用上述数据确定了玉米冠层吐丝动态模型参数;进行了模拟吐丝百分率对植株生长速率平均值(PGR_AVE)和标准差(PGR_SD)两个输入参数的敏感性分析;基于果穗生物量累积过程,考虑干旱胁迫条件下冠层内植株个体间PGR的差异,开展开花前后不同干旱胁迫条件下冠层吐丝动态过程模拟;建立ASI与株结实率(株籽粒数占株最大潜在籽粒数的百分比)的定量关系;基于冠层吐丝动态模型模拟的开花后吐丝植株百分率、单株最大潜在籽粒数和株结实率,构建了基于冠层吐丝动态的籽粒数模型,进行了干旱胁迫下的籽粒数模拟与检验。【结果】冠层吐丝动态模型对PGR_AVE和PGR     

How plant density affects maize spike differentiation,kernel set,and grain yield formation in Northeast China?

A two-year field experiment was conducted to evaluate the effects of plant density on tassel and ear differentiation, anthesissilking interval(ASI), and grain yield formation of two types of modern maize hybrids(Zhongdan 909(ZD909) as tolerant hybrid to crowding stress, Jidan 209(JD209) and Neidan 4(ND4) as intolerant hybrids to crowding stress) in Northeast China. Plant densities of 4.50×104(D1), 6.75×104(D2), 9.00×104(D3), 11.25×104(D4), and 13.50×104(D5) plants ha~(-1) had no significant effects on initial time of tassel and ear differentiation of maize. Instead, higher plant density delayed the tassel and ear development during floret differentiation and sexual organ formation stage, subsequently resulting in ASI increments at the rate of 1.2–2.9 days on average for ZD909 in 2013–2014, 0.7–4.2 days for JD209 in 2013, and 0.5–3.7 days for ND4 in 2014, respectively, under the treatments of D2, D3, D4, and D5 compared to that under the D1 treatment. Total florets, silking florets, and silking rates of ear showed slightly decrease trends with the plant density increasing, whereas the normal kernels seriously decreased at the rate of 11.0–44.9% on average for ZD909 in 2013–2014, 2.0–32.6% for JD209 in 2013, and 9.7–28.3% for ND4 in 2014 with the plant density increased compared to that under the D1 treatment due to increased florets abortive rates. It was also observed that 100-kernel weight of ZD909 showed less decrease trend compared that of JD209 and ND4 along with the plant densities increase. As a consequence, ZD909 gained its highest grain yield by 13.7 t ha~(-1) on average at the plant density of 9.00×104 plants ha~(-1), whereas JD209 and ND4 reached their highest grain yields by 11.7 and 10.2 t ha~(-1) at the plant density of 6.75×104 plants ha~(-1), respectively. Our experiment demonstrated that hybrids with lower ASI, higher kernel number potential per ear, and relative constant 100-kernel weight(e.g., ZD909) could achieve higher yield under dense planting in high latitude area(e.g., Northeast China).     

VarietalDifferences in PlantGrowth,PhosphorusUptake and Yield Formation in Two Maize Inbred Lines Grown Under Field Conditions

Selection for phosphorus (P)-efficient genotypes and investigation of physiological mechanisms for P-use efficiency in maize has mainly been conducted at the seedling stage under controlled greenhouse conditions. Few studies have analyzed characteristics of plant growth and yield formation in response to low-P stress over the whole growth period under field conditions. In the present study, two maize inbred lines with contrasting yield performances under low-P stress in the field were used to compare plant growth, P uptake and translocation, and yield formation. Phosphorus accumulation in the P-efficient line 154 was similar to that of line 153 under high-P. Under low-P, however, P uptake in line 154 was three times greater than that in line 153. Correspondingly, P-efficient line 154 had a significantly higher yield than P-inefficient line 153 under low-P conditions (Olsen-P=1.60 mg kg-1), but not under high-P conditions (Olsen-P=14.98 mg kg-1). The yield difference was mainly due to differences in the number of ears per m2, that is, P-efficient line 154 formed many more ears under low-P conditions than P-inefficient line 153. Ear abortion rate was 53% in the P-inefficient line 153, while in line 154, it was only 30%. Low-P stress reduced leaf appearance, and delayed anthesis and the silking stage, but increased the anthesis-silking interval (ASI) to a similar extent in both lines. The maximum leaf area per plant at silking stage was higher in P-efficient line 154 than in P-inefficient line 153 under both P conditions. It is concluded that low-P stress causes intense intraspecific competition for limited P resources in the field condition which gives rise to plant-toplant non-uniformity, resulting in a higher proportion of barren plants. As soon as an ear was formed in the plant, P in the plant is efficiently reutilized for kernel development.     

中国玉米地方品种核心种质花期相关性状的表型多样性研究

 【目的】研究中国玉米地方品种资源在抽雄期（T）、吐丝期（S）、抽雄-散粉间隔期（TAI）以及散粉-吐丝间隔期（ASI）等4个花期相关性状上的表型多样性,为玉米地方品种资源表型多样性的整体鉴定与评价提供参考和依据。【方法】选取中国玉米地方品种核心种质库的799份种质,采用多环境试验设计,在植株进入生殖生长期后调查抽雄期、吐丝期、抽雄-散粉间隔期以及散粉-吐丝间隔期等4个花期相关性状的表型观测值,计算其Shannon-Weaver多样性指数,并进行显著性检验,评价中国玉米地方品种资源在这4个花期相关性状上的整体多样性水平。【结果】方差分析表明,不同省、市、地区的玉米地方品种资源在研究的4个花期相关性状上的表型观测值均达到极显著水平的差异,而这4个性状除TAI差异不显著外,T、S以及ASI的Shannon-Weaver多样性指数的差异均达到极显著水平。在6个不同的玉米生态区上,这4个花期相关性状的表型观测值也均达到极显著水平的差异,在Shannon-Weaver多样性指数上,TAI的差异不显著,另3个性状则均达到显著或极显著水平的差异。其中,西南山地玉米区在抽雄期、散粉期、抽雄-散粉间隔期和散粉-吐丝间隔期性状上的Shannon-Weaver多样性指数分别为1.85、1.90、0.88和1.20。【结论】中国玉米地方品种资源在抽雄期、吐丝期、抽雄-散粉间隔期以及散粉-吐丝间隔期等4个花期相关性状上表现出了较高水平的多样性,尤其是西南山地玉米区,在表型观测值和Shannon-Weaver多样性指数上均明显高于另5个生态区,表明西南地区玉米种质资源具有较高的保护价值和利用潜力。     

Evidence of arrested silk growth in maize at high planting density using phenotypic and transcriptional analyses

Increasing the planting density is an effective way to increase the yield of maize(Zea mays L.), although it can also aggravate ovary apical abortion-induced bald tips of the ears, which might, in turn, reduce the yield. While the mechanism underlying the regulation of drought-related abortion in maize is well established,high planting density-related abortion in maize remains poorly understood. Therefore, the present study was designed to investigate the mechanism underlying the ovary apical ab...     

水分胁迫后玉米雌雄穗开花间隔时间(ASI)与产量和抗旱性的关系研究

玉米开花期是对干旱最为敏感的时期.此时受到水分胁迫会导致玉米授粉不良进而影响到产量.通过对454份玉米自交系连续两年的研究,在开花期受到水分胁迫后,玉米雌穗生长减缓,吐丝期延迟,ASI增大,结穗率和籽粒产量严重下降,其中ASI、结穗率与籽粒产量均呈极显著相关.因此,在干旱胁迫条件下对产量进行间接选择时,ASI和结穗率是可供利用的重要耐旱指示性状.ASI可作为抗旱玉米种质筛选的主要指标之一.