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.     

Chemical composition and methane yield of maize hybrids with contrasting maturity

Maize (Zea mays L.) is the most important substrate for biogas production in Germany. This study was conducted to determine the influence of harvest date and hybrid maturity on the yield and quality of maize biomass for anaerobic methane production. In 2004 and 2005, maize hybrids of widely contrasting maturity were grown on a loamy sand soil (Haplic Luvisol) near Braunschweig, Germany. Whole-plant yield was determined several times after female flowering and the biomass analysed for nutrient composition. The specific methane yield (SMY) was measured using 20 l batch digesters. In both experimental years, the late energy maize prototypes had a lower concentration of fat and protein, but higher concentration of ash, detergent fibre, and lignin as compared with the climatically adapted medium-early hybrids. Despite substantially different nutrient concentration among the maize hybrids, no clear-cut association existed between chemical composition and specific methane yield. Contrary to the medium-early hybrids, the late hybrids attained both maximum specific methane yield and maximum methane hectare yields at the final harvest date. In the very long growing season of 2004, the highest individual methane yield of 9370 N m³ ha⁻¹ was obtained by the hybrid with the latest maturity used in the study. It appears that late energy maize, which can take full advantage of the growing season, is better suited for biogas production, provided that the whole-plant dry matter concentration is high enough to produce good quality silage.     

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.     

猪粪沼液施用量对水稻农艺性状和青贮品质的影响

为就地消纳猪场养殖废弃物沼液,降低环境污染,本试验研究了不同沼液施用量对水稻的农艺性状和青贮品质的影响。设计了常规化肥(CF)、空白对照组(CK)和17个N2~N48不同沼液氮水平施肥组,共19个组。随着沼液施用量的增加,水稻分蘖数有显著增大,生物量呈先增加后降低的趋势,N8施肥组生物量最高。青贮稻的质地、色泽和气味总体评分随着沼液施用量的增大呈先增加后降低的趋势。当沼液施用量超过N240%替代氮肥时,青贮稻的pH有显著升高(P<0.05)。与CF和CK相比,沼液N2~N8施肥组中性洗涤纤维略有降低(P>0.05),但沼液N14、N16、N20、N28、N32、N36、N40和N48施肥组NDF有显著的升高(P<0.05)。不同沼液施肥组靑贮稻的可溶性糖、酸性洗涤纤维、粗蛋白和粗纤维与CF相比均无显著变化。与CF相比,沼液N2~N24（除N14）处理组青贮稻的粗灰分含量没有显著差异(P>0.05),但在沼液氮肥(N280%~N480%)超量施用时,粗灰分含量明显降低(P<0.05)。猪粪沼液肥替代化肥有助于提高水稻的生物量,改善青贮饲用品质,但不宜超量施用。     

Quantitative trait loci mapping of forage agronomic traits in six mapping populations derived from European elite maize germplasm

Four agronomic traits were analysed including dry matter concentration (DMC) and dry matter yield (DMY) for stover, plant height (PHT) and days from planting to silking (DPS). We mapped quantitative trait loci (QTL) in three populations with doubled haploid lines (DHL), one RIL population and two testcross (TC) populations derived from crosses between two of the four populations mentioned above to elite tester lines, based on field phenotyping at multiple locations and years for each; 146–168 SSRs were used for genotyping of the four mapping populations. Significant high phenotypic and genotypic correlations were found for all traits at two locations, while DMC was negatively correlated with the other traits. A total of 42, 41, 54, and 45 QTL were identified for DMC, DMY, PHT, and DPS, respectively, with 9, 7, 12, and 7 major QTL for each trait. Most detected QTL displayed significant interactions with environment. Major QTL detected in more than two populations will contribute to marker‐assisted breeding and also to fine mapping candidate genes associated with maize agronomic traits.     

青贮玉米不同器官与产量和品质的相关性研究

为了在培育高产优质青贮玉米新品种过程中,提高选择效率,筛选源库比例适宜,营养品质较好的品系,从整株角度对青贮玉米不同器官与产量和品质的相关关系研究,在田间条件下以31份青贮玉米优良品种/系为试验材料,研究青贮玉米各器官与产量和品质关系。结果表明：选取的不同品种/系青贮玉米的干物质质量、含水量、产量和品质均有较大差异,通过相关分析表明,茎秆、叶片(r2产量=0.528**)和苞叶占总干物质比例与单株含水量和产量呈正相关,籽粒和穗轴占总干物质比例与单株含水量和产量呈负相关;茎秆(r2=0.396*)、苞叶和穗轴占总干物质质量比例与整株中性洗涤纤维含量呈正相关,叶片和籽粒(r2=0.381*)占总干物质质量比例与其呈负相关;茎秆和苞叶占总干物质质量比例与整株酸性洗涤纤维含量呈正相关,叶片、籽粒和穗轴与其呈负相关。茎秆、叶片和苞叶占总干物质质量比例与粗蛋白含量呈正相关,籽粒和穗轴(r2=0.660**)占总干物质质量比例与其呈负相关;茎秆(r2=0.407*)、叶片和苞叶占总干物质质量比例与整株淀粉含量呈负相关,籽粒(r2=0.359*)和穗轴占总干物质质量比例与其呈正相关。     

鲁南地区青贮玉米品种筛选

旨在筛选适宜在鲁南地区种植的青贮玉米品种。以青贮玉米高产、优质为核心,以13份不同青贮玉米杂交种为材料,采用SPSS软件对青贮玉米品种的11个农艺和品质性状进行相关性分析和主成分分析。综合得分在0.5以上的品种高低排序依次为‘京科青贮516’、‘饲玉1号’、‘北农青贮208’、‘饲玉2号’、‘诺达1号’、‘登海605’,但因‘北农青贮208’和‘饲玉2号’锈病发生较为严重,种植风险较大。‘京科青贮516’、‘饲玉1号’、‘诺达1号’、‘登海605’等4个品种农艺性状较好、品质优,综合表现好,适合在山东省鲁南地区种植。     

种植密度对不同类型玉米青贮产量和营养价值的影响

为明确不同类型青贮玉米在临沂地区最佳种植密度,设置了4个密度梯度（60 000、75 000、90 000、105 000株/hm ²）,研究种植密度对专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605饲用产量和营养价值的影响。结果表明：密度对不同类型青贮玉米鲜草、干草产量影响显著,密度增加,青贮玉米鲜草产量和干草产量均先增加后减少,在密度75 000株/hm ²时均获得最高鲜草、干草产量。密度对不同类型青贮玉米粗脂肪、粗灰分、酸性洗涤纤维含量和子粒产量、粗蛋白产量、粗脂肪产量、可消化干物质、相对饲喂价值、无氮浸出物含量和总能量影响显著,密度增加,雅玉8号粗蛋白、粗脂肪含量和可消化干物质、干物质采食量、相对饲喂价值和无氮浸出物含量下降,粗灰分、中性洗涤纤维和酸性洗涤纤维含量呈上升趋势,子粒产量、粗蛋白、粗脂肪产量和总能量先增加后减少,在密度75 000株/hm ²均获得最高子粒、粗蛋白、粗脂肪产量。从饲料总能量来说,专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605在山东临沂地区饲用的最佳种植密度均为75 000株/hm ²。     

Genetic variation among European maize inbreds for resistance to the European corn borer and relation to agronomic traits

The univoltine European corn borer (ECB) has become a major limiting factor for maize (Zea mays L.) production in central Europe. The objective of this study was to survey the genetic variation for ECB resistance in European elite maize germplasm. Eighteen flint and 23 dent inbreds were screened under artificial ECB infestation at two locations in 1993 and 1994. Resistance was assessed by damage rating of broken plants, measurement of tunnel length in dissected stalks, and yield reduction in infested plots relative to insecticide-protected control plots. Flint lines showed significantly greater means for damage rating than dent lines with grain yield reduction of 35% and 24%, respectively. Significant genotypic variances among lines and high heritabilities were found for agronomic traits and damage rating. Heritabilities were intermediate for tunnel length and relative grain yield. Significant associations of days to silking, ear dry matter content, and dry matter yield of the whole plant with damage rating and tunnel length suggested a better resistance in late-maturing, high-yielding inbreds. Genotypic correlations of relative grain yield with tunnel length and damage rating ranged between ?0.46 and ?0.72. Partial correlations, eliminating the effect of flowering time, confirmed these associations. Damage rating of stalks is the most suitable trait for evaluation of ECB damage owing to its high heritability and easy recording. Tunnel length below the primary ear is a useful trait for assessing antibiosis because it is not correlated with days to silking. Inbreds with extreme resistance and susceptibility were identified which can be used as parents for establishing breeding and QTL mapping populations.     

施用沼渣对玉米产量及相关农艺性状的影响

笔者研究了沼渣和化肥不同施肥处理对玉米产量及主要农艺性状的影响,为以牛粪为主要原料的沼渣资源化利用及农牧沼循环农业模式提供理论依据。在海林农场白浆土试验田播种期施入经过发酵的新鲜沼渣,采取沼渣、沼渣+复合肥及复合肥3种施肥模式,施肥量设7个水平。在玉米成熟期和收获期,分别测定株高、穗位高、产量、穗长、穗粗等性状。研究结果表明,沼渣和复合肥混合施用有利于玉米生长和产量提高,其中施用复合肥使玉米穗长、穗粗分别增加17.46%、10.68%;复合肥+沼渣模式可以使玉米穗长和穗粗增加10%左右。施用沼渣可以有效降低株高和穗位高,对防御倒伏有一定作用。沼渣和化肥混施,玉米产量比对照增加50%以上。相关性分析表明,穗长和穗粗与产量性状呈极显著正相关,株高与产量性状间也呈显著正相关,表明在没有倒伏情况下,玉米植株长势越好其产量越高。沼渣可以替代一部分化肥的效应,通过与复合肥按照一定比例混合施用能够提高玉米产量,促进玉米生长。     

青贮玉米品质性状遗传变异及主成分分析

为了鉴定青贮玉米品质性状间的相关和依附关系,对14份青贮玉米材料的22个品质性状检测分析,并进行一般描述统计、遗传变异、相关性及主成分分析。结果表明,参试青贮玉米各品质性状中,脂肪、钾、木质素、淀粉含量的变异系数较大,分别为0.20、0.19、0.17和0.16,表明这些性状在品种遗传选育进程中有较大的改良空间;消化率及能量品质相关性状的变异系数介于0.03~0.08,表明这部分性状难以得到遗传改良;青贮玉米品质性状间相关性较大,适宜采用主成分分析保留品质性状的最重要方面。对测试的22个品质性状进行主成分提取,前3个主成分的累积贡献率达到91.29%,分别代表了青贮玉米的饲用价值、微量元素及粗蛋白成分。     

北京市青贮玉米利用与发展策略

畜牧业是北京农业的重要组成部分,饲料短缺限制了畜牧业进一步发展。青贮玉米具有相对高生物产量和饲用价值,青贮玉米的利用对于缓解饲料短缺问题具有重要作用。通过青贮玉米的应用与推广,提高饲料供应,降低生产成本,促进京郊畜牧业发展具有重要意义。北京玉米种植面积在13.3万hm2左右,品种以普通玉米为主,专用青贮玉米发展较慢,普通型玉米品种作为了青贮玉米来用,存在生物产量低、饲用价值相对较差等问题。针对饲料短缺限制畜牧业进一步发展和青贮玉米利用与发展滞后问题,提出实现种植规模化与服务专业化、解决青贮玉米的制种难题、青贮玉米品种应多样化、青贮玉米利用模式高效化、完善青贮玉米推广、政策扶持与政府引导等多项策略。     

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.     

Dent corn genetic background influences QTL detection for grain yield and yield components in high-oil maize

Despite the well-recognized importance of grain yield in high-oil maize (Zea mays L.) breeding and production, few studies have reported the application of QTL mapping of such traits. An inbred line of high-oil maize designated ‘GY220’ was crossed with two dent maize inbred lines to generate two connected F_2:3 populations with 284 and 265 F_2:3 families. Our main objective was to evaluate the influence of genetic background on QTL detection of grain yield traits through comparisons between the F_2:3 populations. The field experiments were conducted during the spring in Luoyang and summer in Xuchang, Henan, China. Two genetic linkage maps were constructed with a genetic distance of 2111.7 and 2298.5 cM using 185 and 173 polymorphic SSR markers, respectively. In total, 18 and 15 QTL were detected for six grain yield traits in the two populations. Only one common QTL marker was shared between the two populations. A QTL cluster associated with five traits was identified at bin 1.05–1.06, including the shared QTL for 100GW, which demonstrated the largest effect (16.7%). Among the detected QTL, 12 digenic interactions were identified. Our results reflect the substantial influence of dent maize genetic background on QTL detection of grain yield traits.     

我国常用玉米自交系秸秆品质性状及其相关分析

利用近红外反射光谱法对我国91份常用普通玉米自交系和11份高油自交系秸秆的体外干物质消化率（IVDMD）、粗蛋白（CP）、粗脂肪（EE）、可溶性糖（WSC）、酸性洗涤纤维（ADF）、酸性木质素（ADL）、中性洗涤纤维（NDF）7个品质性状进行了分析评价,以探讨秸秆品质性状间的关系以及影响秸秆品质的主要成分。结果表明,各品质性状变异较大,各性状自交系间差异均达极显著水平,IVDMD及其相关品质的含量近似正态分布。不同品质性状变异程度不同,其中WSC含量变异最大,变异系数达33.15%。IVDMD与NDF、ADF、ADL呈极显著负相关,与WSC、EE含量呈极显著正相关,与CP含量显著正相关。影响秸秆品质的性状依次是IVDMD、ADF、NDF、WSC、ADL、CP和EE含量。根据青贮玉米育种的要求,筛选出5份IVDMD和WSC含量高、NDF、ADF含量低的自交系。     

Genotypic variation and relationships between seedling and adult plant traits in maize (Zea mays L.) inbred lines grown under contrasting nitrogen levels

Genotypes with better root development have good nutrient acquisition capacity and may yield better under limited nitrogen (N) conditions and consequently can help reduce the N fertilization rate and hence mitigate some economic and ecological problems. This study focused on the genotypic variation among diverse maize inbred lines for seedling and adult plant traits under contrasting N levels. Seventy-four lines were screened under high and low N levels in a climate chamber and in the field. High phenotypic diversity was observed for seedling and adult plant traits together with moderate to high broad-sense heritability estimates. Seedling total root length and root dry weight were significantly correlated with other root traits in maize. Of the adult plant traits evaluated in the field, the anthesis-silking interval and the leaf chlorophyll contents were significantly correlated with grain yield under both low and high N levels. In one location, the seminal root length was correlated with grain yield both under low and high N levels and the root dry weight was correlated with grain yield under high N. Selection indices based on secondary root traits along with grain yield could lead to an increase in selection efficiency for grain yield under N stress condition. By identifying lines with better root development, particularly lines with longer SRL, it may be possible to select inbred lines with higher grain yield particularly under low N condition.     

影响青贮玉米品质因素研究进展

青贮玉米是反刍动物的重要粗饲料来源。优质的青贮玉米具有生物学产量高、干物质含量高,粗蛋白含量高、淀粉含量高,纤维素含量低,消化率高等特征。青贮玉米的品质很不稳定,受多种因素影响,影响青贮玉米品质的因素主要包括青贮玉米的品种、生长季的栽培管理措施、玉米的收割时间、青贮措施、添加剂等。本文综述影响青贮玉米品质的主要因素,为青贮玉米生产提供一定参考。     

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.     

Reaktion verschiederer Mais-Inzuchtlinien und -Hybriden auf steigendes Stickstoffangebot

Response of maize inbred lines and hybrids to increasing rates of nitrogen fertilizer
The response of 8 flint and 8 dent inbred lines and 16 flint × dent single crosses to three rates of nitrogen fertilizer (80, 160, 240 kg/ha) were tested in the years 1983 and 1984 in field trials at one location. The material represents a broad range of maize genotypes not strongly selected for kernel yield.
The mean kernel yield of all hybrids increased from the lowest to the medium N treatment by 7.6 % in 1983 and by 4.9 % in 1984. The highest fertilizer level resulted in an additional yield advantage in the two years of 6.1 % and 4.4 % respectively. An increased nitrogen rate had a positive effect on plant height, leaf area index, grains/cob, 1000 kernel weight, and protein content. Lodging resistance and dry matter content were not significantly influenced by N treatments. A significant interaction between genotype and N treatment was observed for leaf area index, 1000 kernel weight, and protein content, but not for kernel yield. The correlations of kernel yield with other traits investigated were not consistent over years and nitrogen treatments.     

青贮玉米栽培技术措施与产量品质的关系

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