热带玉米种质在温带玉米育种的应用

本文介绍了玉米域带分布不同的玉米种质特点,重点阐述了在温带地区如何利用热带种质的方法和途径;同时,以育成的温带育种用的热带种质优良自交系S37为例,说明在温带地区玉米育种如何利用热带种质的方法。     

吉林省利用热带亚热带玉米种质的概况

本文概括总结了80年代以来引入、利用热带亚热带玉米种质的现状和进展,并对今后工作提出建议,低纬度玉米种质引入高纬度后,因生态环境不同导致性状发生变化,但不同材料、不同性状间差别较大。其中穗位的温光反应敏感程度大于株高,雌穗分化比雄穗敏感;热带种质的利用,因温光反应程度的不同,应分别采用直接、间接等方法加以利用．     

采用SSR标记研究CIMMYT热带、亚热带和温带种质玉米群体的遗传多样性

遗传多样性是一种重要的自然资源且在未来育种进展中将起到关键性作用。必须要对收集的遗传多样性种质进行有效利用和管理方面的鉴定研究工作。种质收集的最佳规模是要求保留最大的遗传变异和保持最小的冗余性为好。     

诱变育种在改良热带亚热带玉米种质资源中的 应用及前景展望

近10年中国玉米单产几乎没有什么实质性的突破。种质资源狭窄是造成这种现象的一个重要原因。引进热带亚热带种质资源是拓宽温带玉米种质的一个重要途径。但是热带亚热带种质资源引进到温带以后会出现成熟期延迟、营养生长优于生殖生长等现象。针对热带亚热带玉米种质这些特点，诱变可以发挥重要的作用。主要对目前经常应用的几种诱变方法在改良热带亚热带玉米种质资源上的应用前景进行了比较。对将来大规模地运用诱变方法改良外来种质进行了预测。     

热带亚热带玉米种质的研究与利用进展

丰富优异的种质资源是玉米育种工作的基础,而种质基础的宽窄和遗传多样性的丰歉,则是玉米育种取得突破性进展的关键.半个多世纪以来,科技的发展在推动农业生产发展的同时,还趋向于缩小农作物的遗传基础.据统计,目前世界上收集到的玉米品种资源约有 8万多份,其中美国和墨西哥国际玉米小麦改良中心( CIMMYT)各保存 2万多份,我国 15990份 [1].     

热带亚热带玉米种质在温带育种中的应用

本文讨论了热带亚热带种质与温带种质互导的意义和作用,论述了热带亚热带种质和温带种质互导的若干问题及研究利用的前景。     

新疆春玉米区热带亚热带种质利用研究

新疆地区是中国玉米高产区之一,年玉米面积4万hm2.80年代以前,新疆玉米以农家种为主,籽粒和茎秆产量都很低,经济效益不高.     

热带亚热带玉米种质的导入和改良创新研究

把热带亚热带玉米种质按２５％～７５％的不同比例导入温带玉米自交系或育种材料中,进行种质改良和创新研究。选育的热导自交系种质基础较宽;配合力较高;玉米大、小斑病病情指数分别降低６１．５％～７８．９％和５３．８％～６９．４％;青枯病、病毒病株率分别降低８４．１％～９３．２％和８６．７％～９８．２％;成熟期绿叶数增加２．６～４．４倍;自交系自身产量提高２０．０％～５５．６％。表明热带亚热带种质导入温带玉米,可能是拓宽温带玉米种质基础、提高综合抗性和丰产性、创造新种质等方面的有效途径之一。     

Adaptation of tropical maize germplasm to temperate environments

Maize (Zea mays L.) is one of few crops that can offer significant genetic gains with the utilization of genetic diversity. Genetically broad-based germplasm has the potential to contribute useful and unique alleles to U.S. Corn Belt breeding programs not present in current U.S. genome sequences (e.g. B73, NAM, etc.). Our objectives were to determine if unique tropical genetic materials have been effectively adapted to temperate environments and how their agronomic performance was relative to adapted populations. An important long-term objective of the Iowa and North Dakota maize breeding programs has been, in addition to the typical elite by elite line pedigree selection cultivar development process, to adapt exotic and unique germplasm, maximize their genetic improvement, and develop unique products for breeding and commercial uses. Stratified mass selection methodology for earliness has been utilized for the adaptation of tropical and temperate populations to Iowa and North Dakota environments. This method has allowed screening of up to 25,000 genotypes per population cycle at a rate of one cycle per year. In addition, the estimated cost per year our programs had for the adaptation of each population was less than $2,000 which could successfully be applied in any breeding program across the globe. This cost has been less than 1 % of the total cost for finding minor genes on the same trait. Our results showed the successful adaptation of exotic populations was independent from genetic background. We can speculate there are a few major genes responsible for most of flowering date expression. We encourage the use of technology to target traits according to their genetic complexity. Stratified mass selection at the phenotypic level has been successful. Each of the populations with either 25 of 100 % tropical germplasm are available for anyone who may desire to expand the germplasm base of their breeding programs with tropical germplasm adapted to temperate mid- and short-season U.S. Corn Belt environments.     

Introgression of temperate germplasm to improve an elite tropical maize population

The effect of introgression of temperate germplasm into an elite tropical maize population, EV8443SR, was studied for different traits. Two temperate lines, FS14 and DEA, were crossed with EV8443SR. The F1 of each cross was backcrossed to EV8443SR to produce the BC1. F1 and BC1 were subjected to two cycles of random mating. Random sets of S1 families were derived from the tropical-temperate populations and the tropical parent for evaluation in two tropical locations. Introgression of FS14 and DEA into EV8443SR significantly increased earliness, and reduced plant height, number of grains per ear, 1000 grains weight and grain yield. Significant harvest index increases were observed. The effect of introgression on genetic variance of EV8443SR varied with trait and sometimes with cross and location. The highest expected genetic progress was obtained in a tropical-temperate population for most of the traits studied. EV8443SR appeared better than, or pratically equal to, the tropical-temperate populations as a foundation population to improve grain yield and husk cover. This revised version was published online in July 2006 with corrections to the Cover Date.     

中国玉米种质资源的整理与成就

玉米种质资源是选育优良品种的遗传物质基础，搜集原始素材，拓宽种质基础，开展种质鉴定，创新和利用，在玉米品种改良工作中中有重要地位。     

玉米种质创新与自交系培育

培育自交系是玉米杂交育种的物质基础。优异自交系及其组合选配可以促进突破性新品种的诞生。２０世纪７０～９０年代，中国玉米育种家采取多种途径，拓展玉米种质基础，成功地培育出许多综合性状或特异性状优良以及高配合力的自交系，为选育高产优质玉米杂交种创造了条件。１抗病性改良玉米抗病性的垂直抗性是指寄主对病原菌的某一个或多个小种是抵抗或免疫的，而对另一些小种是感病或高感的；水平抗性是指对病原菌的全部小种具有同等水平或同样有效的抵抗能力。例如玉米品种对大斑病具有水平抗性，虽总体感病，但并不严重。自从发现了显性…     

玉米耐低温种质资源的初步鉴定和筛选

摘要：本试验对654份玉米自交系的耐低温特性进行了鉴定,在常温（25℃）和低温（10℃）胁迫下分别测定种子的发芽率以及低温胁迫下的发芽时间。以相对发芽率和平均发芽时间作为耐低温特性评价指标,通过聚类分析筛选到30份强耐低温自交系和43份对低温胁迫强敏感自交系,为培育耐低温玉米新品种和挖掘耐低温相关基因提供种质资源。     

玉米种质资源主要品质性状鉴定与评价

对2003—2004年收集、整理的400份玉米种质资源的主要品质性状进行了鉴定评价。结果表明，不同类型的玉米种质资源中地方品种的粗脂肪、粗淀粉性状和自交系粗蛋白、赖氨酸性状具有更大的遗传多样性。通过鉴定，筛选出一批品质性状优异的玉米种质资源．并对现行玉米种质资源品质的评价标准进行了讨论。     

陕西省几个优异玉米种质资源

为进一步提高选育高产、优质、多抗玉米杂交种效率 ,充分合理利用优良玉米自交系 ,笔者在多年种质资源鉴定、筛选和利用研究基础上 ,对 5个优异玉米种质资源作一综合评价 ,提供玉米育种工作者参考。1　 K12　 1983年陕西省玉米研究所用黄早四 /维春为基础材料 ,经 1983～ 1994年连续自交选育而成。生育期　夏播 90天 ,春播 10 0天。形态特征　幼苗叶鞘浅红色 ,叶片挺直 ,叶色较浅 ;成株叶片挺直 ,18～ 2 0片叶 ,叶色逐渐加深 ;成熟期叶色浓绿。株高 190～ 195cm,穗位高 65～ 70 cm。花丝浅红色 ,抽丝较快 ;雄穗分枝较长 ,护颖绿色 ,花药黄…     

Identification of drought tolerant populations at multi-stage growth phases in temperate maize germplasm

Drought is one of the main abiotic stresses in agriculture worldwide. Drought could increase under the predicted scenario of climate change, particularly in the Mediterranean area. Breeding for drought tolerance requires screening of germplasm in order to identify sources of tolerance; therefore, were evaluated 51 diverse open-pollinated maize populations from various temperate regions under increasing levels of drought at germination, seedling establishment and early growth. There was genetic variability for drought tolerance among populations at all growth phases. Several populations from diverse origins and germplasm groups exhibited high germination across stress treatments. Some of those populations had high ability to sustain root development and showed differential performance depending on the stage of development and the phenotypic aspect considered. In general, BS17 showed high germination rate, fast seedling growth and early vigor under drought. Longlellow and Grano de trigo showed high germination and growth establishment rates, whereas AS3(HT)C3 showed high germination rate and early vigor under drought. The photosynthetic rate, stomatal conductance and transpiration of Enano Levantino/Hembrilla (ELH) and BS17 populations were not affected by drought. Water use efficiency of BS17, ELH, Northwestern Dent (NWD) and Viana was not affected by drought. Some of these populations are promising sources of drought tolerance which can provide different mechanisms of drought tolerance at different stages of plant development. Therefore, these results open new possibilities of breeding for drought tolerance by combining those mechanisms through crosses among potential donors. Furthermore, these findings indicate that it is worthwhile to study the genetic and biological basis of such mechanisms.     

宜机收玉米种质资源的创新与利用

美国先锋、孟山都和德国KWS公司拥有较为广泛的早熟、脱水快及耐密抗倒玉米材料,通过利用这些外引种质资源和当地核心骨干系有机融合,进行种质创新是目前国内玉米育种的有效途径。把脱水快、早熟、抗倒及耐密等性状作为宜机收种质创新和利用的重点。采用常规技术和生物技术相结合的育种方法,选育出脱水快、早熟耐密的高配合力自交系5份,为我国玉米育种提供了宜机收的种质资源。