玉米株型育种研究进展

玉米株型育种涵盖了形态生理生态育种的各个方面,各种株型性状之间相互影响,并最终决定了产量的获得.近年来,人们对玉米的株型进行了大量的研究,针对紧凑型和耐密性的玉米育种研究方兴未艾.本文将回顾玉米株型育种方面的研究进展,包括株型育种的内涵,各种株型性状之间的相关,以及株型性状的遗传等内容.以期对玉米的株型育种提供借鏊和参考.     

玉米杂交组合主要农艺性状与产量的灰色关联度分析

为了探讨玉米杂交组合产量与其他主要农艺性状间关联的主次关系,应用灰色关联度分析法研究13个玉米杂交新组合8个农艺性状对产量的影响及各性状间的相互关系,结果表明与产量的关联度大小依次为单穗粒重>株高>穗位高>穗行数>百粒重>秃尖>生育期>穗长,在育种实践中,应注重对单穗粒重、株高和穗位高的选择,同时结合其余农艺性状的综合表现进行育种,将对产量有一个比较大的提升。     

玉米杂交种主要农艺性状的相关分析

高产是当前玉米育种的主要目标.玉米产量的高低与其农艺性状尤其是产量构成因素有关,产量性状是数量性状,受微效多基因控制,易受环境因素的影响,且性状间彼此关联,某一性状的改变必然导致其他性状的变化.因此,研究各农艺性状与产量间相关性,对于减少玉米高产新品种选育的盲目性,提高育种效率具有重要作用.本试验对玉米7个主要农艺性状与产量进行相关分析,目的在于探索各农艺性状对玉米产量的相关重要性,为进一步提高玉米产量,选育玉米高产品种提供理论依据.     

玉米抗旱育种的研究进展

干旱胁迫严重影响我国玉米的产量,抗旱育种是确保产量最有效的手段.在众多的二级目标性状中,根系的数量与重量、株高与叶卷曲、ASI、ABA等是抗旱育种研究的重点目标性状.     

多叶型玉米研究进展

多叶型玉米具有较多的穗上叶片数与高效的光能利用率,是株型育种与高光效育种的优良材料,同时也是青贮饲用玉米育种的宝贵种质。本文介绍了多叶型玉米的植株特征、产量生理特性、玉米多叶性状的育种应用与遗传研究的概况,并对多叶型玉米的研究工作进行了展望,旨在为多叶种质的育种实践与多叶性状的基础研究提供参考。     

玉米杂交组合及其亲本的株型性状分析

对56个玉米杂交组合及其35个亲本自交系的株型性状进行了分析.杂交组合的株型性状与产量性状的相关分析结果表明,只有个别性状之间存在显著相关;自交系各个株型性状之间的相关分析结果显示,很多性状之间存在显著的相关.同时,对玉米自交系株型性状的聚类分析结果,可以帮助了解自交系株型特征的相似性,从而间接地反映它们遗传背景的差异程度.这些结果对玉米育种工作有一定的参考价值.     

应用多元统计分析玉米农艺性状

在作物遗传育种研究中,产量及其相关性状多属于数量性状范畴,这类性状由多基因控制,易受环境影响使其遗传极为复杂,并且性状间常存在复杂相关关系.产量及其相关性状间的复杂关系使得育种中对以产量为目标的选择极为困难.多元统计分析是研究客观事物中多个变量之间相互依赖的统计规律性综合分析方法.合理利用多元统计分析可以加深对性状间相互关系的遗传规律及各相关性状对产量影响的主次和依存关系认识,为新品种选育和改良提供理论依据.对35个玉米品种(组合)的20个农艺性状应用GGE双标图、因子分析和聚类分析研究,结果表明,平均日产量、千粒重、穗长与产量呈显著正相关;20个农艺性状可综合为6个公因子;以6个公因子为综合指标对35个品种(组合)聚类结果聚成17个类群,其中G8、G14、G12、G10和G17为综合性状优良品种(组合).     

黄淮海玉米自交系氮利用效率相关性状分析

为了阐明不同玉米自交系间氮效率差异特征,筛选优异的氮高效种质,改良玉米的氮素利用效率,为玉米氮高效育种方面的研究奠定基础.以平均产量和氮效率为评价指标并结合抽雄期、散粉期、成熟期、株高、穗位等二级性状,对25份目前在黄淮海应用的核心种质和自育玉米自交系材料进行相关性分析及氮利用效率评价.相关性分析结果表明,氮效率在2种不同的氮处理条件下与散粉-吐丝间隔期、平均产量都呈极显著正相关,与株高分别呈显著和极显著正相关,即3个性状可作为评价玉米自交系材料氮效率高低的指标.方差分析结果显示,在低氮和高氮条件下,散粉-吐丝间隔期、平均产量及株高均存在极显著的差异.将高氮条件与低氮条件下的平均产量进行分析并结合株高和散粉-吐丝间隔期等二级性状,鉴定出郑58、WK858和9058这3个玉米自交系材料可在氮高效育种中作为供体亲本来改良玉米的氮素利用效率.丰富了氮高效种质资源,评价了不同玉米材料的氮素利用效率,揭示了不同材料对氮素的反应程度,为氮高效育种提供材料以及自交系的选育和合理的利用肥料提供理论基础和技术支撑.     

玉米杂交种产量与产量构成因素的相关和通径分析

通过玉米产量构成因素与产量的相关和通径分析,研究产量构成因素对产量的作用方式和大小,为玉米高产育种提供理论依据.本试验以85个玉米杂交组合为研究对象,通过随机区组试验进行鉴定,收集参试品种的穗长、穗粗、穗行数、行粒数、500粒重、出籽率等6个主要产量构成因素与单株产量,采用DPS数据处理软件的回归分析程序进行遗传相关和通径分析.结果表明:对产量影响最大的因素是行粒数,其次是粒重和穗粗,它们与产量呈极显著正相关(r=0.421 1,0.450 2,0.473 7),对产量的直接通径系数也较大(P=0.562 5,0.449 9,0.370 8);增加行粒数、粒重和穗粗,并兼顾其他农艺性状是提高玉米产量的有效途径.     

玉米主要农艺性状的通径分析

高产育种仍然是当前玉米的主要育种目标。本文利用玉米主要农艺性状的遗传相关系数进行通径分析,将各农艺性状与产量的相关部分为直接效应和间接效应,从而明确其在产量构成中的相对重要性,以便为高产育种提供参考信息。     

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。     

A QTL atlas for grain yield and its component traits in maize (Zea mays)

Grain yield and its component traits are essential targets in maize breeding. These traits are genetically complex and controlled by a large number of quantitative trait loci (QTL). The aim of this study was to compile reported QTL and major genes for grain yield and its component traits in a QTL atlas, as a valuable resource for the maize community. To this end, 1,177 QTL related to maize yield were collected from 56 studies published between 1992 and 2018. These QTL were projected to genetic map “IBM2 2008 Neighbors”, which led to the identification of 135 meta-QTL. Some genomic regions appear to be hotspots for yield-related meta-QTL, often affecting more than one of the investigated traits. Moreover, we catalogued 20 major maize loci associated with yield and identified 65 maize homologs of 21 rice yield-related genes. Interestingly, we found that a significant proportion of them are located in meta-QTL regions. Collectively, this study provides a reference for QTL fine-mapping and gene cloning, as well as for molecular marker-assisted breeding of yield-related traits in maize.     

4个非洲玉米地方种育种潜力初步研究

为进一步改良和有效利用4个非洲玉米种质提供理论依据,以中国常用的5个自交系为测验种,采用不完全双列杂交设计(NCⅡ),对在四川地区能正常散粉结实的4个非洲玉米地方种进行配合力和育种潜力分析。结果表明,20个顶交组合的株高、穗位高及生育期趋向于对四川生态条件的适应,具有较强的抗病性和抗倒折性,其中来自几内亚比绍编号FDP1种质具有较高的一般配合力,与中国温带血缘的‘丹340’有较强的对照优势,对拓展中国西南地区玉米种质资源、创新杂优模式有一定利用价值。     

玉米产量相关性状Meta-QTL及候选基因分析

借助IBM2 2008 Neighbors高密度玉米遗传图谱整合了1994—2012年文献发表的玉米产量性状(穗行数、行粒数、粒重)584个QTL。采用元分析方法,确定了22个穗行数、7个行粒数和44个粒重Meta-QTL。根据B73基因组序列进行产量相关基因的重定位,在Meta-QTL区段内分别获得10个玉米产量基因和12个与水稻7个产量基因同源的候选基因,分别位于玉米染色体Bins 1.04、1.06、1.07、2.04、2.06、3.04、4.05、4.07、4.09、5.03、5.04、5.05、7.02、8.03、9.03、10.06和10.07。玉米产量性状Meta-QTL及相关候选基因分析可以为分子标记辅助育种和基因克隆提供有用的信息。     

Evaluation of three cycles of full-sib reciprocal recurrent selection in two maize populations from the Northeast of Spain

In Europe a heterotic pattern commonly used in maize breeding is “American Dent × European Flint”. Maize breeding programs generally use only a small portion of the useful genetic variability present in the local open-pollinated varieties which, otherwise, have a poor performance that hampers their use. Two maize composites, EZS33 formed by open-pollinated flint varieties from dry or Mediterranean Spain, and EZS34 from USA dent populations, were developed in Zaragoza (Spain). Both were subjected to three cycles of full-sib reciprocal recurrent selection (RRS) for yield. The objective of our study was to evaluate after three cycles of selection the effect of RRS. The selection significantly increased yield in the population crosses (3.0 % per cycle) and in the crosses of the populations with testers of different origin. The correlated responses for the population crosses in other agronomic traits like flowering and early vigor were in the desired direction, but plant height was reduced. We propose that stover yield or related traits could be included in selection programs as selection criteria to prevent their decline. The adapted population increased the frequency of favorable alleles for yield, but the inbreeding depression counteracted their effect on the mean. RRS had a positive effect on other traits. According to our data, RRS can be useful to develop improved populations from which it would be possible to develop lines with improved both specific and general combining ability with different heterotic groups. We conclude that the heterotic pattern “Mediterranean Spain × US Dent” is potentially very useful for maize breeding for adaptation to Mediterranean conditions and an interesting source of cultivars for low-input agriculture.     

玉米杂交种水分利用效率及相关性状分析

为充分发挥玉米杂交种的水分利用效率,实现玉米高产、高效的目的,本研究以中国生产和推广应用的玉米杂交种为材料,在多变低水条件下,根据成熟期产量水分利用效率剖析其高效性。研究结果表明,不同玉米杂交种间其水分利用效率存在较大的变异范围,玉米杂交种水分利用效率存在着丰富多样的类型;水分利用效率相关性状方差分析结果表明,产量水分利用效率各构成性状在品种间存在着较大差异,不同玉米品种可利用不同性状达到水分的高效利用;简单相关和偏相关分析结果表明,与水分利用效率密切相关的性状是穗行数、行粒数和百粒重。因此,在生产应用中应因地制宜选用不同玉米杂交种,在品种选育过程中应重视相关性状的选择。     

Creation of new maize germplasm using alien introgression from <Emphasis Type="Italic">Zea mays</Emphasis> ssp. <Emphasis Type="Italic">mexicana</Emphasis>

Zea mays ssp. mexicana, an annual wild relative of maize, has many desirable characteristics for maize improvement. To transfer alien genetic germplasm into maize background, F₁ hybrids were generated by using Z. mays ssp. mexicana as the female parent and cultivated maize inbred line Ye515 as the male parent. Alien introgression lines, with a large range of genetic diversity, were produced by backcross and successive self-pollinations. A number of alien introgression lines with the predominant traits of cultivated maize were selected. Genomic in situ hybridization (GISH) proved that small chromosome segments of Z. mays ssp. mexicana had been integrated into the maize genome. Some outstanding alien introgression lines were evaluated in performance trials which showed 54.6% hybrids had grain yield greater than that of hybrid check Yedan12 which possessed 50% Ye515 parentage, and 17.1, 9.9% hybrids had grain yield competitive or greater than those of Nongda108 and Zheng958, which were elite commercial hybrids in China, respectively. The results indicated that some of the introgression lines had excellent agronomic traits and combining ability for maize cultivar, and demonstrated that Z. mays ssp. mexicana was a valuable source for maize breeding, and could be used to broaden and enrich the maize germplasm.     

Combining ability and testcross performance of drought‐tolerant maize inbred lines under stress and non‐stress environments in Kenya

Drought and poor soil fertility are among the major abiotic stresses affecting maize productivity in sub‐Saharan Africa. Maize breeding efforts at the International Maize and Wheat Improvement Center (CIMMYT) have focused on incorporating drought stress tolerance and nitrogen‐use efficiency (NUE) into tropical maize germplasm. The objectives of this study were to estimate the general combining ability (GCA) and specific combining ability (SCA) of selected maize inbred lines under drought stress (DS), low‐nitrogen (LN) and optimum moisture and nitrogen (optimum) conditions, and to assess the yield potential and stability of experimental hybrids under these management conditions. Forty‐nine experimental three‐way cross hybrids, generated from a 7 × 7 line by tester crosses, and six commercial checks were evaluated across 11 optimum, DS and LN sites in Kenya in 2014 using an alpha lattice design with two replicates per entry at each site. DS reduced both grain yield (GY) and plant height (PH), while anthesis–silking interval (ASI) increased under both DS and LN. Hybrids ‘L4/T2’ and ‘L4/T1’ were found to be superior and stable, while inbreds ‘L4’ and ‘L6’ were good combiners for GY and other secondary traits across sites. Additive variance played a greater role for most traits under the three management conditions, suggesting that further progress in the improvement of these traits should be possible. GY under optimum conditions was positively correlated with GY under both DS and LN conditions, but GY under DS and LN was not correlated. Our results suggest the feasibility for simultaneous improvement in grain yield performance of genotypes under optimum, DS and LN conditions.     

玉米耐旱分子育种研究进展

干旱是玉米生产的主要非生物胁迫因子之一,培育耐旱品种可以有效地保持其在干旱环境下的产量稳定性。目前,随着生物信息学数据库的不断完善及基因组学技术的发展,耐旱通用QTL的发掘以及关联分析技术在功能标记开发上的应用,新的耐旱相关转录因子／基因的克隆都为解释玉米耐旱性的复杂遗传网络和分子育种提供了新的机遇和方法。本文综述了耐旱基因组学研究进展及其在玉米耐旱分子育种上的应用。     

玉米产量及产量相关性状QTL的图谱整合

利用生物信息学方法,借助高密度分子标记遗传图谱IBM2 2008 neighbors,利用图谱映射和元分析的方法,对不同试验中定位的400个玉米产量及产量相关性状QTL进行了图谱整合,构建了玉米产量及产量相关性状QTL的综合图谱和一致性图谱。结果表明,玉米产量及产量相关性状QTL在10条染色体上呈非均匀分布,第1染色体上最多,第10染色体上最少;发掘出96个玉米产量及产量相关性状的“一致性”QTL;关联性较强的产量性状的QTL常集中在相同或相近的座位上。