作物远缘杂交育种的途径及其实质

作物远缘杂交的育种可操作性及效果多年来颇有争议,科学家对物种起源与进化的研究恰恰是指导作物远缘杂交育种的理论基础。物种形成理论研究表明生命的共同起源是远缘杂交的理论基础,生物多样性是远缘杂交的物质基础。生物种间的繁殖隔离机制是远缘杂交不亲和性障碍的根源所在,而物种形成方式又为克服远缘杂交的不亲和性提供了理论依据。其中异域性物种形成方式下的生殖隔离具有不彻底性,是克服远缘杂交受精前不亲和性的理论根据;同域性物种形成方式中多倍体化的方式对远缘杂交受精后不亲和性的克服具有较强的指导意义。本文在通过对以上方面的阐述,剖析了远缘杂交的障碍来源、克服途径及实质,为作物远缘杂交育种工作提供参考。     

作物农田蒸散计算模型的研究

农田蒸散是指田间条件下,作物棵间蒸发和蒸腾之和,它涉及土壤作物大气系统,受气象、作物和土壤等多种因素的制约。本文从田间试验出发,综合考虑影响农田蒸散的各种因素,建立了不同作物（棉花、玉米和冬小麦）农田蒸散的计算模型,为今后农业生产中的合理灌溉、节...     

Ustilago maydis populations tracked maize through domestication and cultivation in the Americas

The domestication of crops and the development of agricultural societies not only brought about major changes in human interactions with the environment but also in plants' interactions with the diseases that challenge them. We evaluated the impact of the domestication of maize from teosinte and the widespread cultivation of maize on the historical demography of Ustilago maydis, a fungal pathogen of maize. To determine the evolutionary response of the pathogen's populations, we obtained multilocus genotypes for 1088 U. maydis diploid individuals from two teosinte subspecies in Mexico and from maize in Mexico and throughout the Americas. Results identified five major U. maydis populations: two in Mexico; two in South America; and one in the United States. The two populations in Mexico diverged from the other populations at times comparable to those for the domestication of maize at 6000-10000 years before present. Maize domestication and agriculture enforced sweeping changes in U. maydis populations such that the standing variation in extant pathogen populations reflects evolution only since the time of the crop's domestication.     

在杂交作物分子育种中利用普通核雄性不育的几个可能途径

由一对隐性基因控制的普通核雄性不育性遗传方式能够满足对植物最佳雄性不育系选育的要求,是水稻等作物杂种优势利用的极好遗传工具。如果能解决其不育系繁殖问题,将优于现有的其他杂种优势利用方式。克隆出普通核雄性不育性的可育基因,通过叶绿体转化,将核雄性不育性可育基因向普通核雄性不育株细胞质转移,创造普通核雄性不育株的保持系;通过种子成熟后表达的启动子;和以位点特异性重组技术为基础的基因开关以及化学诱导启动子的利用,都可能繁殖出100％不育株率的普通核雄性不育系,创造普通核雄性不育性利用的新途径,对植物杂种优势利用产业有十分重要的意义。     

杂草与作物竞争模型研究进展

杂草的历史与人类农业史并存。最早科学报道竞争现象是在１４世纪,而开始杂草与作物竞争关系的定量研究则是在本世纪初叶［１］。杂草科学研究较农业病虫害研究起步晚,与许多发达国家相比,我国杂草科学在基础理论方面比较落后,但应用方面发展较快。从系统生态学的高度研究杂草与作物竞争关系是杂草科学研究的一个重要领域,前人为此作了许多有益的工作,并建立了有关的模型,这些模型为解决草害问题起了应有的作用。下面就杂草与作物竞争经验模型的建立、杂草与作物竞争的动态模拟研究、杂草与作物竞争研究在杂草科学管理中的应用等三个…     

Biological nitrogen fixation in mixed legume-cereal cropping systems

Cereal/legume intercropping increases dry matter production and grain yield more than their monocultures. When fertilizer N is limited, biological nitrogen fixation (BNF) is the major source of N in legume-cereal mixed cropping systems. The soil N use patterns of component crops depend on the N source and legume species. Nitrogen transfer from legume to cereal increases the cropping system's yield and efficiency of N use. The use of nitrate-tolerant legumes, whose BNF is thought to be little affected by application of combined N, may increase the quantity of N available for the cereal component. The distance between the cereal and legume root systems is important because N is transferred through the intermingling of root systems. Consequently, the most effective planting distance varies with type of legume and cereal. Mutual shading by component crops, especially the taller cereals, reduces BNF and yield of the associated legume. Light interception by the legume can be improved by selecting a suitable plant type and architecture. Planting pattern and population at which maximum yield is achieved also vary among component species and environments. Crops can be mixed in different proportions from additive to replacement or substitution mixtures. At an ideal population ratio a semi-additive mixture may produce higher gross returns.     

From Diploids to Allopolyploids: The Emergence of Efficient Pairing Control Genes in Plants

Polyploidy has played a major role in the evolution of higher plants. Precise control of chromosome pairing is vital for conferring meiotic regularity, and hence reproductive stability in allopolyploids. In this review, we examine whether strong evidence has accumulated for the presence and activity of pairing control genes in different allopolyploid species that are entirely bivalent forming and that display a strict disomic inheritance. We show that very good evidence has been adduced in Triticum species, Avena sativa, Festuca arundinacea, Brassica napus, Gossypium hirsutum, and G. barbadense, and in amphidiploids related to the diploid species Lolium perenne, L. multiflorum, and L. rigidum. More circumstantial evidence has been obtained for polyploids in the genera Aegilops, Hordeum, Nicotiana, and Coffea, which have received far less attention than the other species. Although these pairing regulators seem to control different processes operating throughout the premeiotic interphase and the meiotic prophase, little is known about their precise mode of action. We present three hypotheses that have been proposed to explain the origin and evolution of pairing control genes; none of them has been supported by direct evidence, and the origin of most pairing suppressors is still unknown. Accordingly, the study of pairing control genes is still an important task for understanding the stabilization and establishment of allopolyploid species.     

种保素对几种作物根际微生物效应的影响

熹龙种籽保生素(以下简称种保素)为复合营养功能型生物制剂,被列为九五国家级新产品(证书号:5120610060784)。经全国农业技术推广服务中心在全国多个省区几年的试验示范和推广应用,结果在玉米、小麦、棉花、油菜、甜菜、花生等多种作物上拌种施用,能提高发芽率,提早出苗,促进根系发育,叶绿素含量增加,植株生长健壮,具有显著的增产效果1)。作物生长状况与其根际微生物有着非常密切的关系。作物生长期间活跃的新陈代谢作用为根际微生物提供大量的营养物质,产生明显的根际效应,同时根际微生物对根际养分也有显著的活化作用,促进植物的生长发育…     

Natural hybrids from Saccharomyces cerevisiae, Saccharomyces bayanus and Saccharomyces kudriavzevii in wine fermentations

Several wine isolates of Saccharomyces were analysed for six molecular markers, five nuclear and one mitochondrial, and new natural interspecific hybrids were identified. The molecular characterization of these Saccharomyces hybrids was performed based on the restriction analysis of five nuclear genes (CAT8, CYR1, GSY1, MET6 and OPY1, located in different chromosomes), the ribosomal region encompassing the 5.8S rRNA gene and the two internal transcribed spacers, and sequence analysis of the mitochondrial gene COX2. This method allowed us to identify and characterize new hybrids between Saccharomyces cerevisiae and Saccharomyces kudriavzevii, between S. cerevisiae and Saccharomyces bayanus, as well as a triple hybrid S. bayanusxS. cerevisiaexS. kudriavzevii. This is the first time that S. cerevisiaexS. kudriavzevii hybrids have been described which have been involved in wine fermentation.     

In Silico Analysis of Crop Science： Report on the First China-UK Workshop on Chips, Computers and Crops

A workshop on ＂Chips, Computers and Crops＂ was held in Hangzhou, China during September 26-27, 2008. The main objective of the workshop was to bring together China and UK scientists from mathematics, bioinformatics and plant molecular biology communities to exchange ideas, enhance awareness of each others＇ fields, explore synergisms and make recommendations on fruitful future directions in crop science. Here we describe the contributions to the workshop, and examine some conceptual issues that lie at the foundations and future of crop systems biology.