Reciprocal differences for forage traits in single and three-way crosses of maize

Eleven flint inbreds of maize were crossed with 11 dent inbreds according to a balanced incomplete factorial mating design to produce 66 single crosses (2W) in both reciprocal forms. Additionally, six three-way crosses (3W) were also produced in both reciprocal forms. These hybrids were evaluated for 11 forage yield and quality traits in 1983 and 1984 at three sites in Germany. Highly significant reciprocal differences were observed for nine traits in the 2W. The respective variance component estimates amounted to 2–33% of the variance component due to crosses. On average, flint × dent 2W had lower dry-matter content (DMC) than dent × flint 2W and a 1 % greater dry-matter yield (DMY) of forage. Three-way crosses produced on singles exhibited greater DMC (3%) and DMY (5%) of the ear, metabolizable energy content (MEC) of stover (1%), and DMC and DMY of forage (2%) than their reciprocal forms produced on lines. Based on this study, because of their minor importance, routine testing for reciprocal differences among 2W hybrids is not recommended.     

Evaluation of early-maturing European maize inbreds for resistance to the European corn borer

The European corn borer (ECB) has become a serious pest for maize cultivation in Central and Western Europe. This study was conducted to evaluate resistance against ECB in a cross section of the European maize germplasm. A total of 115 flint and dent inbreds were evaluated for resistance under protected and artificial infestation conditions at two German sites in 1993. Resistance to ECB was assessed by damage rating before harvest, tunnel length in dissected stalks, and relative yield under infestation compared to protected control plots. Means for damage rating of stalks were significantly higher in flint lines than in dent lines. Artificial infestation reduced grain yield by 31% in flint lines and 20% in dent lines. Significant genotypic variances among lines and high genetic ratios (GR) were found in both flint and dent lines for all agronomic and ECB resistance traits. Exceptions were relative yield of stover in both germplasm groups and tunnel length in flint lines. Phenotypic correlations between agronomic and resistance traits were moderate to low. Damage rating was negatively correlated with days to silking and dry matter yield of stover in both germplasm groups. In vitro digestibility of stover was not associated with ECB resistance. Correlations of relative grain yield with tunnel length below the ear and damage rating were significantly negative, even though their magnitude was low. Our results indicate substantial genetic variation among European inbred lines for resistance to the univoltine ECB. Among all resistance traits measured, damage rating of stalks is best suited for assessment of ECB resistance in breeding programs because of its easy recording and high genetic ratio. This revised version was published online in July 2006 with corrections to the Cover Date.     

陕西省不同年代玉米品种产量和氮效率性状的变化

明确陕西省不同年代玉米产量和氮效率性状响应氮肥的变化趋势,对西北旱区玉米高产氮高效品种选育具有重要的实践意义。本文以1981—2010年间陕西省12个玉米主栽品种为材料,于2011年和2012年在典型旱区陕西长武进行3个氮水平(0、120和240 kg hm–2)的田间试验,分析了不同年代玉米品种农艺和氮效率性状变化趋势。结果显示,不同年代玉米品种籽粒产量随氮水平增加而提高,在施氮0、120和240 kg hm–2处理下籽粒产量增益分别为每年46、65和83 kg hm–2。所有氮水平下2000—2010年间品种产量和生物量显著高于1980—1989年间品种,而秸秆产量变化不明显;现代玉米品种(2000—2010年)产量的增加归因于穗粒数、千粒重和生物量的提高。不同年代玉米品种消光系数随氮水平增加而降低,说明现代玉米品种(2000—2010年)较老品种(1980—1989年)叶片直立,截获更多的光能,致使产量和生物量高。随着年代的递进,玉米品种氮肥农学利用率呈递增趋势,在低氮水平下现代品种氮肥利用效率最高,且显著高于老品种。氮肥农学利用率与氮吸收效率(NUpE)和花后氮素积累量呈显著相关(r=0.75;r=0.72),而与氮生理效率(NUtE)和花前氮素积累量相关性不显著(r=0.42;r=0.39)。说明现代玉米品种氮肥农学利用率提高主要来自氮肥吸收效率和花后氮素积累量的增加。上述结果表明,陕西玉米育种应注重穗粒数、千粒重、氮吸收效率性状和株型结构改良,低氮环境压力选择将有助于旱区玉米高产氮高效新品种培育。     

18个玉米自交系氮效率性状的配合力分析

以不同类群的18个玉米自交系为母本,6个标准测验种为父本,利用NC-II设计,组配108个杂交组合,对亲本自交系氮效率相关性状进行统计分析,并对杂交组合的产量及氮效率相关性状进行配合力分析。结果表明,吐丝期叶绿素相对含量在2个施氮处理下均与氮效率呈极显著正相关(r = 0.553, 0.639),可作为评价亲本自交系氮效率高低的指标;从氮效率2个构成方面来看,不施氮处理下氮利用效率起主要作用,而施氮处理下氮吸收效率起主要作用。亲本氮效率配合力分析表明,在氮高效品种选育中,应保证亲本至少有一个是氮效率一般配合力(GCA)较高的自交系,并选择由其组配的氮效率特殊配合力(SCA)高的组合;双亲的配合力氮效率总体效应(TCA)决定着组合F₁代的产量及氮效率,TCA可作为选育氮高效杂交组合的理论依据。母本自交系BL12、BL48分别在施纯氮225 kg hm^-2 (N225)和450 kg hm^-2 (N450)处理下,具有较高的GCA效应,是较好的氮高效育种材料,其杂交组合BL12×178、BL48×掖478分别在N225,N450处理下表现较优,是优良的氮高效杂交组合。     

Silage yield and quality traits in elite maize hybrids and their relationship to elemental concentrations in juvenile plants

European silage maize is cultivated for animal feed and biogas production. We evaluated 210 factorial crosses of elite dent and flint lines in multilocation trials for agronomic and quality traits together with biomass and shoot concentrations of 10 elements in juvenile plants. Significant genotypic variances, mainly due to general combining ability variance of the dent lines, and high heritabilities were observed for dry matter yield (DMY) and quality traits. DMY was not correlated with quality traits, but methane fermentation yield (MFY) and metabolizable energy content (MEC) showed significant correlations with starch and fibre content. Concentrations of elements N,P,S,K were positively correlated with each other but only in few cases correlated with DMY and quality traits. Parent lines with contrasting P concentrations differed in root morphology traits. Results support DMY as primary trait for selection of silage maize hybrids, but MFY is of negligible importance in breeding for biogas contrary to MEC for animal feed. Neither biomass nor elemental composition of juvenile plants were of predictive value for final DMY or quality traits.     

黑龙江省不同年代玉米杂交种产量对种植密度和施氮水平的响应

明确不同年代春玉米生产力对种植密度和氮肥水平的响应特征及其趋势,对高产高效的耐密品种选育和密植抗倒栽培具有重要的理论参考和技术指导意义。本文以黑龙江近50年来第一积温带大面积种植的8个典型春玉米品种为材料,于2009和2010年进行密度和施肥的田间试验,比较不同年代主栽品种生产力演变特征。结果显示,黑龙江省1970s—2000s玉米品种更替过程中,单株生产力与群体产量均明显提高,平均增幅分别为16.96 g 10年^-1和790 kg hm^-2 10年^-1;植株空秆率和倒伏率显著下降,株高、穗位、单株叶面积、穗粒数、千粒重显著提高。随着密度的提高,各年代玉米的单株产量呈显著下降趋势,群体产量呈抛物线形上升,群体最高产量的理论密度增幅为3 507株 hm^-2 10 年^-1;空秆率显著提高,但倒伏率仅1970s和1980s的品种呈递增趋势;株高、单株叶面积、棒三叶面积、穗粒数与千粒重均呈现下降趋势,穗位随密度增加呈显著上升趋势。各年代品种株高、穗位、单株叶面积和千粒重随氮肥水平提高呈增加趋势。在150~450 kg hm^-2的施氮水平范围,随着氮肥水平的提高,各年代品种增产效果不明显。各主要指标在年代、密度和氮肥水平之间存在显著的互作效应。对照东北玉米现有的品种特性、种植密度和施肥现状表明,选育耐密品种和实施密植抗倒栽培的增产潜力大,在现在的施肥水平上进一步提高种植密度是东北春玉米高产增效耕作栽培的技术创新方向。     

浅埋滴灌下分期追氮对玉米花后光合特性、氮素利用和产量的影响

为研究浅埋滴灌下不同氮肥追施方式玉米花后光合特性、氮素利用和产量形成的差异,以氮肥一次性追施(CK)和氮肥分期追施(NFQ) 2种氮肥追施方式的玉米为研究对象,对其花后叶源特性、光合特性、氮素利用和产量及产量构成因素进行比较分析。结果表明,2018—2020年NFQ花后叶源特性显著优于CK,其叶面积指数、叶绿素SPAD值和叶片氮素含量分别平均较CK提高了6.35%、11.02%和5.34%。NFQ花后光合特性亦显著优于CK,其净光合速率、瞬时光能利用率、瞬时水分利用效率和瞬时羧化速率分别平均较CK提高了6.98%、4.28%、20.49%和12.73%。NFQ氮素积累转运量均显著高于CK,其氮素积累量和转运量分别平均较CK提高了23.73%和19.29%。NFQ产量均显著高于CK,试验年份平均增产9.40%,穗粒数和千粒重的显著提高是增产的主要原因。本研究认为,西辽河平原井灌区玉米生产的适宜氮肥追施方式为拔节期、大口期、吐丝期按3:6:1比例追施。     

增施氮肥、硼肥对花期遮阴条件下玉米籽粒产量的影响

遮阴已成为影响夏玉米产量的重要因子,提高玉米耐阴性可为高产、抗逆栽培提供理论依据。以‘苏玉29’为试验材料,系统研究了小喇叭口期增施氮肥、硼肥缓解花期遮阴胁迫对夏玉米形态建成、物质积累和产量的影响。结果表明:遮阴处理降低了株高、茎粗、单株叶面积和干物质积累量,并延长了散粉吐丝间隔期。与遮阴处理比,小喇叭口期增施硼肥、氮肥不同程度提高了株高、茎粗、单株叶面积和干物质积累量,且同时增施硼肥、氮肥增幅最大。遮阴处理显著增加了秃尖长,降低了穗粒数和粒重,增施硼肥氮肥缓解了遮阴对突尖长、穗粒数和粒重的影响。增施硼肥、氮肥和同时增施硼肥、氮肥处理产量分别较遮阴处理提高36.7%、8.0%和43.1%。遮阴处理降低叶面积影响干物质积累,产量的降低与突尖增长、穗粒数减少和粒重降低有关。小喇叭口期增施硼肥和氮肥是缓解花期遮阴对产量不利影响的有效措施。     

缺氮对细胞质雄性不育玉米产量和光合特性的影响

在露天池栽条件下, 比较研究了玉米细胞质雄性不育系(CMS)与其同型可育系的产量构成及其光合特性对氮素亏缺的响应。结果表明, 在相同氮素供应水平下, CMS的产量显著高于其同型可育系, 平均增产达11.5%, 缺氮条件下千粒重、收获指数显著提高, 而穗粒数差异不显著。花后CMS玉米叶片具有较高的含氮量、叶面积指数、叶绿素含量和可溶性蛋白含量, 且在生育后期降低缓慢, 延长了有效光合持续期, 延缓了植株衰老进程。不育植株生育后期的净光合速率(P_n)、细胞间隙CO₂浓度(C_i)和气孔导度(G_s)均显著高于其可育系, 且气体交换参数对缺氮反应不敏感。不育系的叶绿体荧光参数实际光化学效率(FPSⅡ)、电子传递速率(ETR)和最大光化学效率(F_v/F_o)在生育后期也保持较高水平。说明不育植株生育后期在光合能力、电子传递和光能转化方面均具有明显优势, 其产量提高可能是籽粒充实期叶片生理质量和光合效率共同提高的结果。     

Genetic Diversity for RFLPs in European Maize Inbreds

Restriction fragment length polymorphisms (RFLPs) have been proposed for predicting the yield potential of different types of cross. Their has been evaluated in 15 flint and 12 dent inbreds from the European maize (Zea mays L.) germplasm as well as in 68 F₁ crosses (21 flint × flint, 14 dent × dent, and 33 flint × dent) produced between them. The materials were evaluated for F₁ performance and midparent heterosis of grain yield, dry matter content (DMC) and plant height in two environments in Germany. Genetic distances (GDs) between parental lines, calculated from RFLP data of 194 clone-enzyme combinations, showed greater means for flint × dent (0.67) than dent × dent (0.62) and flint × flint (0.55) crosses. Cluster analysis based on GDs resulted in a clear separation of flint and dent lines and agreed well with pedigree information. For the complete set of 64 crosses analyzed (excluding 4 crosses between closely related lines) correlations of GD with F₁ performance and heterosis were significant for all traits except F₁ performance of DMC. When separate calculations were performed for individual subjets of crosses, correlations of GD with Fl performance and heterosis were significantly positive (0.48 ≤ r ≤ 0.80) for all traits in the flint × flint crosses, but not significant for the subsets of flint × dent and dent × dent crosses. Our results confirm those of previous investigations in that the predictive value of RFLP data is restricted to crosses between lines from the same heterotic group, and cannot be applied to crosses between lines from genetically divergent heterotic groups.     

氮肥后移对超高产夏玉米产量及氮素吸收和利用的影响

采用田间试验研究了氮肥后移对超高产夏玉米产量、氮素吸收积累和氮肥效率的影响,旨在了解超高产夏玉米(≥ 12 000 kg hm^-2)的氮素吸收和转运特性,为实现夏玉米超高产合理施肥提供依据。结果表明,夏玉米施氮显著增产,增产幅度为9.62%~15.95%,氮肥后移比习惯施氮增产2.27%~5.33%。超高产夏玉米吐丝后氮素吸收积累量占总积累量的40.30%~47.78%,保证后期氮素养分充足供应对于夏玉米达到超高产水平至关重要;氮肥后移可促进超高产夏玉米后期的氮素吸收积累,降低夏玉米茎和叶片氮素的转运率,显著增强灌浆期夏玉米穗位叶硝酸还原酶活性,提高灌浆期叶片游离氨基酸含量,增加蛋白质产量;氮肥后移比习惯施氮的氮肥利用率提高1.88%~9.70%、农学效率提高0.96~2.21 kg kg^-1,以“30%苗肥+30%大喇叭口肥+40%吐丝肥”方式施用氮肥的产量和氮肥利用效率最佳。     

Maize Smut Induced by Ustilago maydis (D. C.) Corda – Reaction of Maize Hybrids and Lines to Smut Disease

A field experiment was carried out during the growing seasons 1982, 1983 and 1984 to evaluate the reaction of different maize hybrids and lines to smut disease and to give further informations on the effect of environmental factors on smut incidence.
The kernels of 17 different maize hybrids and 17 inbred line were planted in the field and the stand was maintained constant of 30 plants per row during the respective years. Each plant was subjected to an artificial infection by dropping 2 ml of U. maydis -spore suspension into the leaf whorl at 6–8 leaf stage. Field observations, concerning the number, the size and location of smut galls were recorded for each individual plant whenever the symptoms appeared. The reaction of maize genotypes was evaluated on a new classified system and the differential response was correlated with the changes ol meteorological data.
The results indicated that hybrids: Circe LG9, E1, Kaceplns, Limac-LG11 and RA 94A x RA 320 as well as lines: F2, L1, L2, L8, RA 94A, RA 320, W33 and W401 were highly resistant; while the hybrids E2, F7 x EP1.J and Giga as well as lines: EP1J, F115, L5 and L6 were highly susceptible. The reaction of these genotypes exhibited an identical behaviour during the 3 years. The remaining genotypes were unstable and showed differential response to degree of infection and location of smut galls. The increase of smut infection in 1982 relative to that recorded in 1984, under the same wet weather conditions, was attributed to the increase of air temperature and sunshine duration. Under dry weather condition, as in 1983, increasing temperature and sunshine duration had little effect on smut incidence.     

长期施肥对夏玉米叶片氮代谢关键酶活性的影响

以“国家褐潮土土壤肥力与肥料效益长期监测基地”的大田肥料长期试验为平台,研究了长期施肥对夏玉米叶片中硝酸还原酶（NR）、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)和谷氨酸脱氢酶(GDH）活性的影响。结果表明,长期N、P、K化肥配合（NPK处理）以及N、P、K化肥与有机肥或秸秆配合施用（NPKM与NPKS处理）,叶片氮代谢酶（NR、GS、GOGAT和GDH）在籽粒灌浆时期均具有较高的活性,有利于玉米籽粒产量的形成;长期N、P、K化肥非平衡施肥的处理（NP、N、NK、PK处理）以及不施肥的CK,叶片氮代谢酶活性变化差异较大,且活性高峰期和籽粒灌浆关键期时间不一致,植株整体生产能力较弱,玉米籽粒产量较低。不同的酶对籽粒产量的贡献不同,因而系统研究长期定位配比施肥处理下玉米叶片的氮代谢酶活性具有重要的意义。     

典型玉米自交系氮素吸收利用特点的研究

在大田条件下,对8个代表性的玉米自交系在不同施氮水平下的氮素吸收与利用特点及与氮效率相关的一些性状进行了研究。结果表明：玉米自交系在产量、生物量和氮累积量上存在显著的差异。通过玉米自交系各性状与氮效率的关系的分析表明,低氮胁迫下,应选择抽丝期穗位叶叶绿素含量高、穗位叶叶面积大、籽粒含氮量高和氮收获指数大的自交系,高氮处理条件下,应选择抽丝期生物量大和成熟期生物量大的自交系。通径分析表明,氮吸收和氮利用效率对氮效率的作用均是直接作用大于间接作用。3个施氮水平条件下,对氮效率的直接作用是氮吸收效率大于氮利用效率。在低氮条件下,氮吸收效率的直接作用更强,而氮利用效率对氮效率的直接作用是随着施氮量的增加逐渐增强。在氮2、氮3处理中,吸收效率和利用效率的共同影响导致了产量差异,并且是吸收效率的影响较大;高氮处理则主要是吸收效率的影响。     

施氮对不同基因型玉米籽粒发育和氮效率的影响

为解决生产中氮肥过度施用造成的资源浪费和环境污染问题,选择适宜的玉米氮高效品种至关重要。在不同施氮水平下,对不同基因型玉米籽粒发育及氮效率的差异进行了比较,采用田间试验,对屯玉99(TY)、潞玉19(LY)、先玉335(XY)3个玉米品种在4个施氮水平N0、N1、N2、N3(0,80,160,240 kg/hm2)条件下的籽粒发育和氮效率进行对比分析。结果表明,各品种玉米的籽粒干质量与氮含量差异在N3水平下最大,依次表现为N3N2N0N1;随着施氮量的增加,双高效型先玉335和高氮高效型屯玉99籽粒发育速率加快,籽粒干质量和籽粒氮含量在各生长时期都有明显增加,增施氮肥可以有效提高其氮肥利用率,促进氮在玉米植物体内的转移;低氮高效型潞玉19在低氮(N0、N1)水平下保持较高的产量,但随施氮量的增加,其籽粒干质量和氮含量无明显变化,产量甚至有所降低,导致氮利用效率降低。双高效型先玉335在低氮和高氮条件下都有较好的产量,是适合广泛种植的玉米品种;低氮高效型潞玉19适合在贫瘠土壤和施氮条件不良的条件下种植。     

综合农艺管理对夏玉米叶片生长发育及内源激素含量的影响

叶片可直接反映玉米植株的营养状况,是光合作用的主要场所,与干物质积累和产量形成密切相关。本研究以郑单958 (ZD958)为试验材料,以T1代表农民习惯处理; T2代表在T1的基础上,增加种植密度,推迟收获,降低施肥量,并优化施肥时期; T3代表在T2的基础上进一步增加种植密度和施肥量; T4代表在T3的基础上,降低种植密度和施肥量;N代表施氮量处理,设N0、N1、N2和N3分别为0、129.0、184.5和300.0kgNhm~(–2),研究综合农艺管理对夏玉米叶片生长及内源激素的调控作用。综合农艺管理措施包括优化耕作方式、种植密度、施肥量、施肥时期和收获时间等。结果表明,施氮量不足导致IAA、ZR和GA_3含量降低, ABA含量升高,叶片SPAD值、叶面积指数(LAI)及比叶重均显著降低;随施氮量的增加,叶片IAA、ZR和GA_3含量增加,ABA含量降低,LAI、SPAD和干物质积累量均显著增加。综合农艺管理处理可调节叶片内源激素含量,其中T4处理IAA、ZR和GA_3含量较T1处理分别高23.1%、9.8%和14.7%;ABA含量降低12.4%;叶片LAI适宜, SPAD值增加4.2%,最终单株干物质积累量增加12.6%。综合农艺管理在降低施氮量,配合最佳的农艺管理方式下,可调节内源激素含量,增加叶片SPAD和比叶重,有利于单株干物质积累,这可能是促进夏玉米产量增加的重要原因之一。     

Genetic variation in testcrosses of European maize inbreds for resistance to the European corn borer and relations to line per se performance

The European com borer (ECB) Ostrinia nubilalis H. is a major pest in World maize Zea mays L. production. Objectives of this study were to (1) investigate the genotypic variance and covariance in testcrosses of European flint and dent inbreds for ECB resistance and agronomic traits, and (2) estimate the correlation between line per se and testcross performance for ECB resistance traits. A total of 16 flint and 24 dent inbreds and their testcrosses with two testers from the opposite germplasm pool were evaluated in four and three German environments, respectively. Using artificial infestation with ECB larvae, resistance was assessed by damage rating of stalks, tunnel length in dissected stalks, and relative yield of infested plots compared with protected plots. Yield losses due to ECB damage in testcross hybrids amounted to 40%. Significant genotypic variances between flint and dent lines and high heritabilities were found for damage rating of stalks for both line per se and testcross performance. Heritabilities were low or intermediate for tunnel length and relative grain yield. Correlations between line per se and testcross performance were tight for the damage rating of stalks and moderate for tunnel length and relative yield in both flint and dent germplasm. For damage rating of stalks, per se performance of lines tested in a few environments can be used to predict their testcross performance. In contrast, assessment of testcross performance for tunnel length and relative yield requires evaluating testcrosses with several testers in multi-environment trials.     

玉米杂交种及其亲本苗期性状对低氮胁迫的动态响应

以玉米杂交种先玉335及其亲本（PH6WC、PH4CV）和豫玉22及其亲本（综3、87-1）为试验材料,通过水培方法,设置低氮（0.04mmol/L,LN）和正常氮素（2mmol/L,CK）水平2个处理,分别在培养3、7和14d后,对其幼苗生物量积累、叶片和根系表型、叶绿素及氮素含量等进行分析,探究低氮胁迫下玉米杂交种及其亲本幼苗性状的动态变化。结果表明,玉米苗期根系对低氮的响应要早于地上部,且杂交种对低氮的响应比亲本更为迅速。在CK和LN处理下,杂交种幼苗的多个性状均存在中亲和超亲优势,豫玉22的根尖数、根系氮积累量占比和先玉335的总根长、根表面积及根尖数的杂种优势在3个时间点与CK处理相比均有较大幅度提高。通过耐低氮指数分析发现,杂交种的耐低氮能力介于2个亲本之间或与其中1个亲本接近。     

PEG模拟干旱胁迫下玉米胚芽鞘长与其抗旱性的关系分析

以6份抗旱性不同的玉米自交系为试材,用不同浓度的PEG-6000(polyethylene glycol,PEG)渗透溶液进行模拟干旱胁迫处理,分析玉米萌芽期中胚轴长、胚芽鞘长及苗长的变化,并将其与田间干旱胁迫处理下相应玉米自交系产量及产量相关性状的抗旱指数进行相关分析,以期揭示萌芽期玉米幼苗相关性状与其抗旱性的关系。结果表明:(1)萌芽期随着PEG浓度增加,玉米自交系胚芽鞘长、中胚轴长及苗长都呈下降趋势,其中苗长降低幅度最大,平均降幅为14%,中胚轴长次之,平均降幅为11%;(2)方差分析表明,不同玉米自交系幼苗的中胚轴长、胚芽鞘长在自交系间及PEG浓度间差异极显著,苗长在PEG浓度间差异极显著;(3)花期田间干旱胁迫下,各玉米自交系的千粒重、穗粒数及产量较正常灌溉明显下降,且其平均降幅分别为8%、14%、13%;(4)通过玉米田间产量及产量相关性状抗旱指数与萌芽期各性状相关性分析表明,中胚轴长与千粒重、穗粒数及产量的抗旱指数呈显著或极显著正相关。胚芽鞘长与千粒重、穗粒数及产量的抗旱指数呈极显著正相关,而在5%的PEG-6000渗透溶液模拟干旱胁迫下,胚芽鞘长与千粒重抗旱指数相关系数最高为0.832。因此,胚芽鞘较长的自交系其抗旱性较强,胚芽鞘长度可作为玉米早期抗旱性筛选的重要指标。     

不同灌水次数与氮肥运筹对‘豫教5号’叶面积指数及产量的影响

为给冬小麦提供“更合理、更节约、更高效”的水肥运筹技术方案,以‘豫教5号’为试验材料,采用三因素裂区方法研究了不同灌水次数和施氮处理对小麦叶面积指数和产量的影响。结果表明,灌水次数、施氮量以及基追比例分别对小麦叶面积指数、产量及构成因素有显著影响。在W1（底墒水）处理下叶面积指数与施氮量均呈线性正相关关系;在W2（底墒水+拔节水）、W3（底墒水+拔节水+灌浆水）处理条件下,拔节期、孕穗期、抽穗期的叶面积指数与施氮量呈线性正相关关系,抽穗后20天与施氮量则呈二次曲线关系,且以N3R2为最大值。在不同灌水次数条件下,产量、穗数、穗粒数与施氮量呈二次曲线关系,千粒重随施氮量的增加呈线性下降趋势。在灌溉底墒水+拔节水+灌浆水、施氮量为240 kg/hm²及基追肥5:5处理组合下实现了水肥的高效配合,产量、穗数、穗粒数分别为8609.60 kg/hm²、688.2×10⁴株/hm²、37.9粒,其中产量比对照W1N0 (3517.5 kg/hm²) 增产144.8%。由此可知,在小麦生长后期降雨量偏少的黄淮豫东地区,小麦生产中灌溉水的节约空间相对较小,氮肥的节约空间则相对较大。