我国玉米育种的发展进程及对未来育种目标的初探

半个多世纪以来,我国玉米杂种优势的利用对提高玉米单产起到了至关重要的作用,但随着经济的发展和人民生活水平的提高,迫切需要提高玉米的产量和品质,比如南方广泛种植的郑单958。尤其近年国外新品种的介入如先玉335等,这就给我国的广大育种科技人员提出了新的挑战。如何对已往的育种思路、育种方法、育种目标进行调整已经引起了广泛关注。本文通过育种实践提出了对未来育种目标的初探,供种业同行探讨     

黄淮地区现代玉米育种目标

半个多世纪以来,我国玉米杂种优势的利用对提高玉米单产起到了至关重要的作用,但随着国民经济的发展和人民生活水平的提高,迫切需要进一步提高玉米的产量和品质,比如黄淮夏玉米广泛种植的郑单958。尤其近年利用国外种质材料育成的玉米新品种先玉335等品种的介入,给我国的广大育种科研人员提出了新的挑战。如何对已往的育种思路、育种方法、育种目标进行调整已经引起了广泛关注。我们通过近几年的育种实践提出了未来玉米育种的目标,供科研育种同行探讨。     

对我国玉米科研生产中若干问题的思考

我国是玉米生产和消费大国，育种单位众多，但所育品种同质化程度高，个性化品种少，品种寿命短。应组建生态区玉米育种中心，协作开发，提高玉米育种水平。对玉米品种审定、区试、扩展DNA指纹鉴定用途等提出建议。     

调整玉米育种方向 加强专用玉米品种选育

20世纪80年代以来，我国的国民经济快速增长，人们的生活水平逐年提高，玉米作为国民主食的时代已成为历史，全方位主攻的普通玉米高产育种方向已不能适应时代要求，亦难有效抵御我国加入WTO后世界玉米市场对我国玉米产业的巨大冲击。迅速调整玉米育种方向，全面转入专用玉米育种，重点突出高赖氨酸和粮饲兼用型玉米新品种选育，兼顾人们食用和工业用玉米育种，并对各类玉米进行大规模的产业化开发，可促进我国养殖业的快速发展，改善国民的膳食结构，有效地缓解加入WTO后对我国玉米产业的冲击。     

新世纪初发展我国玉米遗传育种科学技术的思考

玉米是我国主要饲料、工业原料和粮食作物.建国50年来,随着遗传育种研究水平提高,以及农业综合技术全面发展,全国玉米平均单产提高2.7倍,为保障粮食安全做出重大贡献.但是,我国玉米单产刚刚超过世界平均水平,与发达国家相比还有较大差距.近十多年,我国玉米单产平均年增长率,不仅低于发达国家,而且低于发展中国家.除环境等因素而外,不得不承认包括遗传育种在内的玉米科技水平还相当落后.社会经济发展要求大幅度提高玉米产量,改善品质.加入WTO后国际竞争更加激烈,我国玉米生产面临严峻挑战和前所未有的机遇.我们应该抓住机遇,通过科技体制改革,加强玉米遗传育种科学技术研究,从应用基础和现代生物技术方面取得突破,使我国玉米生产和玉米科学技术赶上世界先进水平.可供玉米育种利用的基因资源日渐贫乏,仅靠自然进化和传统人工选择难以满足国民经济发展对玉米生产不断增长的需要.需要将传统遗传育种研究与现代生物技术结合,从分子水平上认识玉米遗传变异机理,在充分发掘玉米基因库现有遗传资源的同时,利用基因工程技术打破生殖隔离,转化利用其他物种的有益基因,创造更为丰富的遗传变异,培育性状更加全面、生产性能更好的玉米新品种.现代生物技术发展迅速,有关基因资源及其知识产权的国际竞争愈演愈烈,我们必须奋起直追,才不会处于被动局面.玉米育种的主攻方向是高产、优质和适应性.新世纪初我国玉米生产所面临的新形势,为这三方面的主攻目标贼予了新的含义.高产是永恒的主题,玉米还有很大的增产潜力.高产育种的基础是种质创新,培育高水平自交系,并通过组合选配提高杂种优势水平.优质是市场的需求,不同用途的品种对品质有不同的要求,主要包括营养品质、商品品质、加工品质和适口性四个方面.适应性是稳产的保证,耐旱、抗病、耐贫瘠、抗虫是提高玉米品种适应性的关键.针对玉米生产和遗传育种科学技术研究亟待发展的现状,建议加强应用基础和高新技术研究,为玉米科学技术和玉米生产持续全面发展打下坚实基础;建立玉米行业协会,抓住农村经济结构调整有利时机,推进玉米产业化进程;深化农业科技体制改革,把公益性研究与商业化育种分开,加大对公益性研究的支持,制定有关政策,鼓励多方面投资,组建种子企业和科研单位联合的大型商业化育种公司.     

中国爆裂玉米育种三十年

回顾中国爆裂玉米的育种研究历程,对中国爆裂玉米育种的起步、发展经历、育种成果及品种水平进行概述。80年代伴随我国的改革开放和经济发展,中国爆裂玉米育种研究应运而起。1986年我国第一个爆裂玉米综合种"黄玫瑰"问世,1997年第一个单交种"沈爆2号"诞生,2003年首批国审爆裂玉米单交种育成,2018年我国第一个球形花爆裂玉米新品种通过国家审定。从综合种到省审单交种、国审单交种,品种单产跨越了两个增产10%的台阶,近年新育成的品种单位面积产量比初期的综合种增产1倍以上。目前,我国爆裂玉米育种已经发展到品质育种阶段,由过去的混合花型发展到球形花和典型的蝶形花型,整体的品种水平已经达到或超过进口玉米。分析和讨论目前中国爆裂玉米研究和产业发展存在的主要问题。     

旅大红骨种质的改良和利用

20世纪80年代至今，我国育成的玉米新品种杂种优势并没有显著提高，在由基因型决定的玉米单产达到一定阈值水平之后，进一步提高单产必须在杂种优势和抗性水平上突破。扩增、改良和创新种质是玉米育种的发展方向。培育高产、优质、多抗、广适和高配合力自交系是玉米育种的目标。旅大红骨种质对育种和生产做出了很大贡献。为更好利用其抗性好的特点，研究其遗传改良和利用的依据、目标、途径、材料及方法，为继续利用原有的典型杂种优势模式和创建新的杂种优势模式奠定基础。     

玉米高产育种研究

论述吉林省玉米单产对全省乃至全国玉米及粮食产量的影响,分析了我国玉米产量水平低下的原因和东北春玉米尚有较大的增产潜力,并比较了中、美国家玉米品种的差异,提出了高产超高产育种计划:即高产超高产育种方向、目标和选系方法。认为稳产育种与高产育种应同步进行;中低产田以Lan.类群与塘四平头类群为杂优模式对,向适应性强、稳产杂交种方向选育;高产田以Reid类群与旅大红骨类群为杂优模式对,向超高产杂交种方向选育。     

“十二五”以来我国玉米分子育种研究进展

分子育种是玉米遗传育种快速发展的最重要推动力之一。近些年来,我国在玉米分子育种相关领域已经取得了重大进展。文章综述从"十二五"至今,国内研究者利用分子育种技术在玉米种质遗传多样性和遗传结构分析、相关性状基因/QTL发掘和基因克隆等方面的新进展,促进玉米分子育种技术能够更好地应用于育种研究中,为提高育种效率提供思路和参考。     

加入WTO后对玉米育种研究的思考

就玉米育种研究在我国加入WTO以后如何面对机遇和挑战。如何面对激烈的市场竞争，怎样调整育种方向，怎样改变传统的育种模式，从三个方面进行了阐述。首先普通玉米育种研究要进行改革的调整。一要丰富和创新种质资源，丰富育种材料，从面越过玉米育种所处的平台期，选育出产量高，综合抗性好的新品种。二是利用生物技术提高育种水平。三是开展品质育种，注意选育高淀粉、高油、高赖氨酸的玉米新品种。其次是在继续搞好普通玉米育种的同时，积极开展特种玉米的研究与利用，选育甜玉米、糯玉米、青饲玉米和爆裂玉米新品种 ，从而增强玉米育种的竞争力。最后是育种的改革，玉米育种与种业机构要走强强联合的道路，组建育种、制种、加工、销售和开发创收一体化的集团军，从而增强自身生存能力，增强抵御市场冲击的能力，使玉米育种在未来的发展中立于不败之地。     

Pharmacokinetics of Marine-Derived Drugs

Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.     

La pourriture fongique des tubercules de pomme de terre en atmosphère contrôlée

Résumé Fusarium culmorum et, dans une moindre mesure,F. avenaceum, F. sambucinum, Colletotrichum coccodes etCylindrocarpon sp. ont été isolés de tubercules entreposés en atmosphère contr?lée (AC) et atteints de pourriture grave. Des expériences d'inoculation de tubercules avec 10 espèces ou variétés fongiques et conservation en AC à 8 et 10°C ont montré que: 1) les champignons non pathogènes en atmosphère normale (ex.:Cylindrocarpon sp.) le devenaient en AC, 2) ceux qui étaient faiblement pathogènes en atmosphère normale étaient nettement plus virulents en AC (ex.:F. culmorum), 3) les espèces ou variétés virulentes en conditions d'air normales (Fusarium sulphureum etPhoma exigua var.foveata) ne provoquaient pas de pourriture plus grave en AC et leur activité pouvait même être légérement freinée.

---

Summary The extensive rotting of tubers which occurred during storage trials in controlled atmospheres has led to a mycological and pathological study of the rots. The most frequently isolated species wasFusarium culmorum althoughF. avenaceum, F. Sambucinum, Coletotrichum coccodes and aCylindrocarpon sp. were also present. Tubers of cvs Bintje and Ulla were inoculated with 19 isolates of 10 fungal species or varieties associated with rotting of stored tubers (Table 1). The tubers were incubated at 8 or 10°C in normal or controlled (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂) atmospheres and the extent of rotting was determined a month later (Tables 2 and 3 and Fig. 2). Species which were weakly virulent in a normal atmosphere (variousFusarium spp. andPhoma exigua var.exigua) were clearly more aggressive in the controlled atmosphere and this was especially evident in the case ofF. culmorum. Species ot pathogenic in a normal atmosphere under experimental conditions (Colletotrichum coccodes, Cylindrocarpon sp.,Phoma eupyrena) caused rotting in the controlled atmosphere. The two species which were virulent in a normal atmosphere (F. sulphureum andP. exigua var.foveata) were also virulent in the controlled atmosphere and in some cases the extent of rotting was even less. As a general rule, rotting caused by weakly virulent fungi was greater in both cultivars in the controlled than in a normal atmosphere.

---

Zusammenfassung Eine starke F?ulnis von in Kontrotrollierter Atmosph?re gelagerten Kartoffelknollen veranlasste eine mykologische und pathologische Untersuchung. Der am h?ufigsten isolierte Pilz warFusarium culmorum. F. avenaceum, F. sambucinum, Colletotrichum coccodes undCylindrocarpon sp. wurden ebenfalls bestimmt. Neunzehn St?mme von 10 Pilzsorten oder-Arten welche bei Lagerf?ulnis vorkommen (Tab. 1) wurden auf Knollen der Sorten Bintje und Ulla inokuliert. Die Lagerung wurde bei 8 oder 10°C under Normalbedingungen oder kontrollierter Atmosph?re durchgeführt (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂). Der F?ulnisgrad (Abb. 1) wurde nach einem Monat bonitiert. Die Ergebnisse sind in den Tabellen 2 und 3 dargestellt und in der Abb. 2 illustriert. Unter in Normalbedingungen nur schwach virulente Arten (verschiedeneFusarien undPhoma exigua var. exigua) waren deutlich aktiver in kontrollierter Atmosph?re. Dies was besonders der Fall fürF. culmorum. Pilze, die im Versuch unter Normalbedingungen nicht pathogen waren (Colletotrichum coccodes, Cylindrocarpon sp., Phoma eupyrena), haben unter kontrollierter Atmosph?re Sch?den verursacht. Hingegen werden die beiden unter Normalbedingungen sehr pathogenen Arten (F. sulphureum undP., exigua var.foveata), durch kontrollierte Atmosph?re wenig beeinflusst. Es wurde sogar in einigen F?llen eine gewisse Verringerung des F?ulnisbefalls beobachtet. Ganz allgemein haben die getesteten kontrollierten Bedingungen die Entwicklung der Pilzf?ulnis an beiden Kartoffelsorten gef?rdert, speziell durch Pilzarten, welche unter Normal-bedingungen wenig Sch?den verursachen.

     

Marine Pharmacology in 2016–2017: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems,and Other Miscellaneous Mechanisms of Action

The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016–2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories.     

Effects of Micronutrient Deficiencies on Human Health: Its Status in South Asia

SUMMARY

Vitamin A, iodine, and iron deficiencies affect large numbers of people worldwide. A deficiency of one or more of these micronutrients adversely affects the physical and mental abilities of humans. South Asia contains a high percentage of these individuals, not just because of its large population, but also the prevalence of deficiency is higher there than in many other parts of the world. The reasons for the high rates of deficiency in South Asia are many, but they include inadequate availability of micronutrient-rich foods, sub-optimal dietary habits, and high rates of infection. Across the region, national plans vary from (a) increasing availability of appropriate foods, (b) introducing new dietary behaviors, (c) improving health status, and (d) directly addressing deficiency through intervention programs. The extent to which each of the countries is making progress toward the goals of these plans can help in understanding the priorities for future efforts to address micronutrient malnutrition. This article discusses the adverse effects of micronutrient deficiencies in humans with special reference to South Asia.     

Management of Soil Micronutrient Deficiencies in the Rice-Wheat Cropping System

Summary

Within the last three decades, the rice-wheat cropping system has triggered, and with time, aggravated soil micronutrient deficiencies in the Indo-Gangetic Plains (IGP). This has largely been due to the shift from an earlier rice and wheat monoculture with low yielding, long duration indigenous varieties, to an intensive rice-wheat rotation cropping system with short duration modern high yielding varieties on the same piece of land. The problems related to micronutrient deficiency in the IGP are more due to the size of its available pools in the soil rather than its total contents and are greatly influenced by crop management, or rather its mismanagement. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, zinc deficiency has reduced in some areas of the region. Meanwhile, the deficiency of Fe, Mn and B has increased in the IGP. Deficiency of Cu and Mo is location specific and can limit rice and wheat yields. The adoption and spread of the rice-wheat system in permeable coarse textured soils, particularly in the western IGP, not only caused iron deficiency in rice but also resulted in the emergence of manganese deficiency in wheat. In highly calcareous and acidic soils, boron is the next limiting micronutrient in crop production after zinc. Bumper rice and wheat harvests in the past decade, the declining use of organic manures in the region and except for the widespread use of zinc sulfate, a general lack of awareness amongst farmers on micronutrient deficiency problems has contributed to micronutrients limiting rice and wheat yields in the IGP. Approaches to alleviating micronutrient deficiencies include matching the crop removals of the micronutrients with its replenishments through their respective external carriers, supplementation through organic sources and mobilization/utilization through cultivation of micronutrient efficient crop cultivars. Identification of efficient micronutrient carriers and finding the optimum rate, mode and time of its application is important in ameliorating the micronutrient deficiencies. This article reviews the extent of micronutrient deficiency and discusses various management options available to reduce micronutrient deficiency induced crop yield reduction for rice and wheat in the Indo-Gangetic Plains.     

Irrigation but not N fertilization enhances seedhead density in plains rough fescue ( F estuca hallii)

Plains rough fescue ( F estuca hallii) is an important forage grass species in western Canada. Seed for use in pastures and ecological restoration is in high demand but supply is limited because F. hallii is an erratic seed producer. Seed producers require an understanding of the factors that influence flowering and seed set in this species. The aim of this study was to assess the effect of irrigation and nitrogen fertilization on the flowering and growth of F. hallii in a native rough fescue prairie in Alberta, Canada. Irrigation had a strong positive effect on seedhead density, whereas fertilization had limited effects on growth and reproduction of F. hallii. These results demonstrate that under field conditions, available moisture is likely to be a key factor driving flowering and seed production in F. hallii.     

Marine Drugs Regulating Apoptosis Induced by Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)

Marine biomass diversity is a tremendous source of potential anticancer compounds. Several natural marine products have been described to restore tumor cell sensitivity to TNF-related apoptosis inducing ligand (TRAIL)-induced cell death. TRAIL is involved during tumor immune surveillance. Its selectivity for cancer cells has attracted much attention in oncology. This review aims at discussing the main mechanisms by which TRAIL signaling is regulated and presenting how marine bioactive compounds have been found, so far, to overcome TRAIL resistance in tumor cells.     

Biochemical and morphological characterization of potato clones differing in their resistance to late blight

Summary Morphological and biochemical parameters that could be involved in resistance to late blight were studied in non-infected and in infected potato hybrids resulting from a cross betweenSolanum phureja, resistant toPhytophthora infestans, and a susceptibleSolanum tuberosum. Some morphological differences between resistant and susceptible hybrids, indicating a positive correlation between stem diameter and phloem thickness in the stem and resistance toP. infestans, were observed. The lignin content in the leaves of the resistant hybrid rose upon infection byP. infestans. In the leaves of the susceptible hybrid, a diminution of the lignin content could be observed upon infection byP. infestans. In the same context, peroxidasic activity raised upon infection byP. infestans in both resistant and susceptible hybrids. Further characterization of the hybrid clones based on the polymorphism of peroxidases was attempted using isoelectric focusing.     

In vitro reproduction in the annual pasture legumes subterranean clover (Trifolium subterraneum L.) and French serradella (Ornithopus sativus Brot.)

Pasture legumes are important components of both mixed farming rotations and permanent pastures in temperate climates. Breeding of two widely sown pasture legumes, subterranean clover (Trifolium subterraneum L.) and French serradella (Ornithopus sativus Brot.), is constrained by the long generation cycle, typically enabling only one generation per year. We hypothesized manipulation of culture medium and conditions would enable the development of a laboratory‐based protocol for in vitro reproduction in subterranean clover and French serradella. In vitro flowering and viable seed set was induced from both species. For subterranean clover, the most effective treatment was culturing on modified MS medium with 1 μm kinetin and 0·1 m sucrose under a 100 μmol m^?2 s^?1 light intensity and continuous photoperiod. For French serradella, culture on a hormone‐free B5 medium with 5 mm NH₄Cl and 0·1 m sucrose under a 100 μmol m^?2 s^?1 light intensity and 20 h photoperiod was optimum. It is expected this technique will have application in accelerating generation turnover within breeding programs, for the study of factors influencing flowering in pasture legumes, and for the propagation of valuable yet enfeebled plants such as embryo‐rescued hybrids.     

Applied Biotechnology to Combat Late Blight in Potato Caused by <Emphasis Type="Italic">Phytophthora Infestans</Emphasis>

Potato is an important crop, grown worldwide. It suffers from many pests and diseases among which late blight, caused by the oomycete Phytophthora infestans, is the worst. The disease is still causing major damage in many potato production areas and control is only possible by applying fungicides frequently. The knowledge on the molecular biology and genetics of the interaction between the plant and the oomycete is developing rapidly. These are relevant fields of study, currently dominated by the discovery of many resistance genes and numerous effector proteins and the analysis of their specific mode of action. These studies may yield essential information needed for the development of durable resistance. The long-term and worldwide effort to breed for resistance so far has had little effect. A novel breeding approach may change this. It is based on cisgenic modification (CM) consisting of marker-free pyramiding of several resistance genes and their spatial and temporal deployment yielding dynamic varieties that contain potato genes only. It is envisioned that this CM approach with potato’s own genes will not only prove societally acceptable but may also result in simplifications in the legislation on use of the CM approach. Various parties in the potato research arena intend to cooperate in this novel approach in a number of developing countries where potato substantially contributes to food security. The use of resources such as land, water and energy improves when the effect of late blight is markedly reduced.