提高玉米育种效率的技术途径

在选育玉米新品种时,要提高育种效率,首先考虑的是应有一个明确的育种目标,其次是种质选择,同时还需考虑育种方法。提出“3群”杂种优势群的概念和“三角形”杂种优势模式;分析了轮回选择、二环选系、单倍体诱导选系的方法及分子育种技术对提高玉米育种效率的作用。结论是:要提高玉米育种效率,应在传统育种技术上下功夫,同时要重视现代生物技术作为辅助手段的应用。     

黄淮海玉米育种的密度选择探讨

玉米育种过程中的密度选择是一个关键因素,自交系种植的密度以及杂交种筛选的密度,关系到所选育品种未来的推广方式与推广价值。从育种实践来看,育种者首先要了解所用的育种材料的适宜密度水平,然后选择适宜的密度去种植、选择,可有效提高选育玉米品种的速度和质量。     

浅谈我国玉米自交系选育的现状和对策

在20世纪80年代初期,我国玉米育种创造了世界玉米育种史上的奇迹,从早期的研发和推广杂交种,到后来攻克了玉米抗病育种技术的难关,以及从双交种过渡到更先进的单交种选育技术,达到了世界先进水平。但是进入20世纪80年代后期,我国玉米育种技术进入缓慢发展阶段,没有突破性进展,只是在抗病育种和籽粒品质上得到了一定的改善,并且及时育成了较抗病的新品种。尤其是近15年问,我国选育的玉米杂交种杂种优势水平没有提高反而下降了,究其原因主要是没有突破性的玉米白交系。而选育优良的玉米自交系是玉米杂交种选育的基础和关键,没有突破性的玉米自交系就不会有突破性的玉米杂交种。     

提高吉林省玉米育种效率的技术途径

提高玉米育种效率主要体现在提高自交系选育的效率。简要介绍了吉林省玉米育种工作的主要方法和成果;并对未来提高玉米育种效率的几种技术途径和方法进行了分析和探讨。     

玉米冬季南繁育种的技术措施

常规育种条件下 ,一年一季地选育玉米自交系一般需要 1 0年左右的时间 ,不能适应现代玉米生产发展的需要 ,利用我国南方冬季温暖的气候条件 ,南北交替种植 ,一年种植玉米二三代 ,可以加速选育世代和种子繁殖 ,缩短育种年限 ,还有助于对性状的异地选择和鉴定 ,从而提高育种的质量和效果。适于冬种玉米的南繁基地 ,以海南岛南部即五指山脉以南的三亚、陵水、乐东等地最为理想。南繁育种必须充分利用南方有利条件 ,克服不利因素 ,促进玉米正常生长发育 ,才能为选育创造有利的条件。南繁实践证明 ,采取以下技术措施 ,是使南繁玉米正常生长发育的…     

对山西省玉米未来育种的思考

玉米是山西省主要的粮食作物,随着社会的发展,对玉米育种提出了更高要求。山西省气候和地形复杂,要因地制宜明确育种方向和采用先进的育种技术,选育适合的品种,使其能有效地提高农业资源的利用效率,从而提高玉米单位面积产量。     

机收玉米新品种MC812的选育

<正>随着我国城镇化发展和人口结构老龄化的变化,农村劳动力越来越短缺,实行玉米生产全程机械化是当前玉米发展的迫切要求。选育早熟、耐密、抗倒和适宜机收的玉米新品种是当前的育种方向。玉米新品种MC812(京审玉2015003)是以优良自交系杂交聚合作为选系材料,利用"高大严"选系方法(即高密度、大群体、严选择)和DH(双单倍体)育种技术,选育而成的     

贵州省紧凑型玉米生产专家系统开发研究

紧凑型玉米杂交种的选育成功是玉米生理育种和生态育种的一大成就.特别是近年来优良紧凑型杂交种的选育,各地相继创造超高产的纪录,不仅标志中国玉米高产育种和高产栽培理论的重大突破,并且对中国玉米生产水平的提高起到了推动作用.     

玉米自交系快速选育新技术

优良自交系的选育是玉米育种工作的基础。目前，玉米育种仍主要采用传统的方法。传统育种方法选育一个自交系至少需5～7年，育种周期长、工作量大，特别是在一年一季的北方，育种进程更加缓慢。各个育种单位都采取南繁加代来加快玉米品种选育进程。但是，南繁加代要耗费大量的人力物力。随着现代生物技术的发展，玉米育种技术研究已取得了一些新的进展，为加速玉米育种进程带来了新的曙光。     

玉米育种理论基础和育种方法

正育种的根本任务是寻求提高玉米的产量和品质,实现稳产、高抗、适应机械化,增加经济效益。选育出市场比较认可的品种是所有育种者共同的目标。育种前提是设计育种目标,建立优良的种质资源及遗传基因库,建立自交及杂交,包括单交、三交及双交的育种方法,目标明确、作业清楚定义、管理严格的育种流程,育种操作与生物技术是相互辅助,兼容而并行的科技管道,应用分子技术,提高玉米育种的有效性、精确性及预期性,提早玉米开花期及适应环境的能力,促进玉米栽培     

我国西南地区玉米育种面临的挑战及相应对策探讨

在剖析西南地区发展玉米产业面临挑战的基础上,反思了西南地区玉米杂交育种存在的主要差距,并根据国内外玉米杂交育种发展趋势和我们的实践,从育种层面提出了应采取的对策措施。育种目标上,重点是抗病与抗虫、耐旱与耐瘠、适合全程机械化生产和耕作制度改革,以及拓展利用营养体优势新型“饲草玉米”。种质创新上,应明确杂优类群、简化杂优模式,系统开展基础种质评价与分析,合成与改良育种用群体,创制育种特异新材料。突破性自交系选育上,应注重特异新基因的发掘与利用,把产量GCA作为重要选择标准,把自交衰退慢的株系作为主要选择对象,自交、姊妹交或混粉交替进行,提高优良基因型频率;加大选系的鉴定力度,并测定产量。育种方法上,应增加种植密度,加大选择压力,实施南北穿梭育种,加快我国南方玉米种子生产基地建设,同时加快高新技术在玉米育种上的应用。     

玉米籽粒主要品质性状的分子遗传研究进展

玉米是全球最主要的粮食作物之一,提高玉米籽粒品质是当今世界玉米育种领域高度关注的问题。因为传统常规育种方法具有育种时间长且转化率低等限制因素,所以解决这一问题最经济有效的方法就是利用分子标记进行辅助选择育种。为了给今后玉米品质性状的分子设计育种提供参考,本研究总结了国内外玉米籽粒品质性状的QTL定位、分子标记辅助改良和候选基因克隆及转基因技术应用的相关研究进展。指出玉米优质基因资源的利用还不够充分,现有分子标记技术在玉米育种中的应用还不够广泛,今后应改进育种方法和品质鉴定技术,以缩短玉米育种周期。     

援西非农业项目玉米育种的策略建议与探讨

通过剖析西非地区玉米品种情况及其面临的问题,提出援西非农业项目玉米育种的策略建议:根据不同国家情况确定育种目标,培育不同类型玉米杂交品种,并注重品种耐旱、耐贫瘠等优良性状的选择;按“地方系”与“外来系”的配对模式组配,提高育种效率,并兼顾自交系一般配合力和产量选择;开展示范与配套技术研究以利于新品种推广等。同时对今后的工作思路进行探讨,加强西非地方种质与引进外来种质的研究利用,针对当地生产条件及收获习惯选育品种,以相对简单科学的试验设计获取完整、正确的试验结果,稳定援外项目育种队伍及为育种成果联合开发寻求出路等。     

Development of in vivo haploid inducers for tropical maize breeding programs

Lack of adapted haploid inducers currently impedes adoption of the doubled haploid technology in tropical maize breeding programs. Our objective was to generate inducers with improved adaptation to tropical conditions. We developed segregating generations from crosses between temperate inducers having haploid induction rates (HIR) of 8–10 % and tropical CIMMYT maize lines (CML; HIR = 0 %) and evaluated these for HIR and agronomic performance under tropical lowland field conditions. The applied pedigree breeding scheme comprising mass selection on individual F₂ plants for highly heritable and visually scorable traits, followed by family-based selection for HIR and other agronomic characteristics in advanced selfing and backcross (BC) generations seems highly suitable for breeding improved haploid inducers with adaptation to different agroecologies. The most advanced tropical inducer candidates (TIC) combine HIR of up to 10 % with improved pollen production, disease resistance, and plant vigor compared to temperate inducers under tropical conditions. Agronomic characteristics were significantly improved in the BC to CML compared to BC to inducers, while mean HIR of both populations were similar, indicating that backcrossing to the adapted parent was suitable to improve adaptation of new inducers without sacrificing high HIR. When screening random open-pollinated maize accessions, HIR of up to 3 % were observed, suggesting that novel genetic variation may be present in maize accessions that could be exploited to improve HIR in maize. In conclusion, tropical inducer development proceeds well, but evaluation of TIC in multi-environment trials needs to be completed before large-scale dissemination can commence.     

Genomic selection and enablers for agronomic traits in maize (Zea mays): A review

Maize is a commodity crop providing millions of people with food, feed, industrial raw material and economic opportunities. However, maize yields in Africa are relatively stagnant and low, at a mean of 1.7 t ha⁻¹ compared with the global average of 6 t ha⁻¹. The yield gap can be narrowed with accelerated and precision breeding strategies that are required to develop and deploy high-yielding and climate-resilient maize varieties. Genomic and phenotypic selections are complementary methods that offer opportunities for the speedy choice of contrasting parents and derived progenies for hybrid breeding and commercialization. Genomic selection (GS) will shorten the crop breeding cycle by identifying and tracking desirable genotypes and aid the timeous commercialization of market-preferred varieties. The technology, however, has not yet been fully embraced by most public and private breeding programmes, notably in Africa. This review aims to present the importance, current status, challenges and opportunities of GS to accelerate genetic gains for economic traits to speed up the breeding of high-yielding maize varieties. The first section summarizes genomic selection and the contemporary phenotypic selection and phenotyping platforms as a foundation for GS and trait integration in maize. This is followed by highlights on the reported genetic gains and progress through phenotypic selection and GS for grain yield and yield components. Training population development, genetic design and statistical models used in GS in maize breeding are discussed. Lastly, the review summarizes the challenges of GS, including prediction accuracy, and integrates GS with speed breeding, doubled haploid breeding and genome editing technologies to increase breeding efficiency and accelerate cultivar release. The paper will guide breeders in selection and trait introgression using GS to develop cultivars preferred by the marketplace.     

不同生态环境对玉米杂交后代选择效果的分析

本文分析了外来X系新种质一优良单交种F2和F3世代的分离群体在不同生态环境下的选择效果。结果表明,在东华北、西北春玉米区优良果穗入选率较高,单穗平均粒重较高;在黄淮海玉米区优良果穗入选率较低,单穗平均粒重较低。认为在东华北、西北生态环境下,有利于对玉米杂交分离后代的产量潜力选择;在黄淮海地区则有利于对多种抗性和病虫害的选择。不同生态环境间的变换地穿梭育种选择,有利于对玉米杂交分离后代的单株的产量潜力和耐多种抗性和病虫害的有效选择。     

全球玉米分子育种专利态势分析

揭示全球玉米分子育种技术发展态势,旨在为国内玉米分子育种领域相关从业人员在科研或产业化方面提供参考。利用文献计量法,结合专家咨询和调研分析,针对全球玉米分子育种的专利年代趋势、技术生命周期、主要来源和受理国家/地区、主要专利权人、技术主题分布进行分析。为阐释典型机构的技术发展历程,依据专利间的相互引证关系,绘制该领域重要专利权人——杜邦公司的技术路线图。最后利用Emergency Indicator算法对专利标题和摘要中的主题词进行创新性得分计算,预测该领域的新兴技术。结果表明,全球玉米分子育种正处于稳步发展阶段,美国是该领域主要的技术来源国家,同时也是主要的技术流向市场,中国专利数量排名第二,但专利质量和海外布局意识有待提高;大型跨国企业是创新技术的主要来源机构,技术体系完善;转基因技术是目前应用最多的育种技术,加倍单倍体、分子标记辅助选择、单倍体诱导等技术为该领域的新兴技术,值得关注。中国应加大对玉米分子育种的扶持力度,捕捉技术空白点提升专利质量和技术竞争力,同时积极推进专利技术在国际市场的布局。     

Participatory plant breeding with maize in Mexico and Honduras

Maize is a staple food crop in many developing countries. However, if seven major maize producing countries are excluded from this group, data indicate that only 34% of the maize area is planted with improved seed despite considerable effort invested in maize breeding. This has led researchers to investigate other options, such as farmer-participatory plant breeding, for delivering the benefits of plant breeding knowledge and technology to farmers in developing countries. This paper describes short-term results from participatory maize breeding studies in Mexico and Honduras. Results from three selection cycles in Mexico suggest that stratified mass selection without pollination control, with selections carried out by researchers in farmers' fields, may be effective at improving yield in farmers' local varieties. In Honduras, mass selection with pollination control, where selections were done by collaborating farmers in their own fields on their own varieties, showed trends (non-significant) towards yield improvement. Farmer selection seemed to offer the greatest yield benefit over experiment station selection on the farm with the lowest yield potential, suggesting that farmer-participatory approaches may be most advantageous in marginal environments where experiment station conditions differ most dramatically from farmers' conditions. These studies highlighted the importance of seed systems knowledge in designing participatory plant breeding programs. For cross-pollinated crops, they also highlighted the need to balance progress from selection and demands on farmers' time and labor in choosing breeding methods. Further work is needed to investigate farmer-participatory breeding approaches that can address post-harvest traits. This revised version was published online in August 2006 with corrections to the Cover Date.     

水分胁迫对不同抗旱型玉米自交系苗期生长的影响

通过水分胁迫处理对不同抗旱型玉米自交系苗期的影响研究,为抗旱育种选择自交系提供选择参考。采用人工控水的方法,研究干旱胁迫对夏玉米抗旱型和对敏感型自交系苗期株高、地上部和地下部分干重、叶面积、比叶重、叶绿素和净光合速等的影响。结果表明：不同抗旱型自交系苗期对水分胁迫的响应不同。抗旱玉米自交系从5叶期开始在干旱胁迫期间的株高、地上部和地下部分干重、叶面积、叶绿素和净光合速率等指标均高于对水分敏感的玉米自交系,且比叶重相对稳定。这表明干旱条件下,抗旱型自交系较普通自交系在苗期能够表现出更好的适应性,本研究对加强抗旱自交系的筛选和选育,进一步提高耐旱节水玉米新品种选择效率具有一定参考价值。     

waxy基因功能标记开发及在糯玉米育种中的应用

为利用分子标记辅助选择加快糯玉米种质资源改良进程,以糯玉米自交系云539和普通玉米自交系昌7-2为材料,通过DNA序列测定和分析,探明糯玉米自交系云539 wx基因属于wx-D7突变类型。根据2个自交系基因组序列差异,开发出waxy基因功能标记FMD7,并通过了表型验证和通用性验证。利用开发的基因功能标记FMD7进行分子标记辅助选择,结合产量、株型和品质性状分析,获得携带wx基因的优良昌7-2改良系6个。利用本研究开发的基因功能标记FMD7进行辅助选择可加快回交转育进程,提高育种效率,为选育高产糯玉米杂交种提供材料基础,同时也为分子标记辅助选择单基因或少数主效基因控制的性状提供理论参考。