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1.
Genotypic influence of both male and female parents on haploid production through interspecific crosses was studied using eight wheat and four maize genotypes. The average numbers of embryos and green haploid plantlets obtained per pollinated floret were 17.6% and 10.1%, respectively. Clear genotypic influence of the wheat genotype was detected, but heterozygosity of the wheat did not affect haploid production. Analogous response to anther culture and interspecific crossing was observed, still a wheat variety which did not respond to anther culture, produced 1.1 plantlets per pollinated spike upon maize pollination. This appears to be a major advantage of interspecific crossing compared to anther culture technique in wheat. Circumstantial evidence is presented for specific wheat × maize interaction on haploid plantlet formation. Rye chromatin enhanced haploid production but only in a complete 1B/1R substitution line. Ovaries with an embryo were found to be dispersed evenly all over the wheat spike, suggesting that within certain limits the developmental stage of ovaries and thus time of pollination within a spike are not as important as it was previously assumed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

2.
F2 populations derived from a half diallel cross between 11 spring bread wheat cultivars were classified according to segregation for heading date in a spring environment. Seventeen populations segregated very late plants, presumably of winter type, resulting from the presence of different Vrn genes in the parents. The objective of the study was to evaluate the performance of these spring x spring crosses grown in a winter wheat environment. F2 plants were selected from six populations and were simultaneously exposed for several generations to the winter wheat environment (Toluca, Mexico, winter) and spring wheat environment (Ciudad Obregon, Mexico, winter; Toluca, spring). Visual selection was conducted on F3-F5 populations for agronomic type relevant to the environment under which the segregating generations were grown. The lines grown in the spring environment performed very well and a number of them were promoted to advanced generation testing. The same lines grown in the winter environment suffered from frost and were almost entirely discarded, proving that spring × spring crosses have limited value for germplasm improvement targeted for conditions similar to the Toluca highland winter environment. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

3.
Intercropping is widely used by smallholder farmers in developing countries, and attracting attention in the context of ecological intensification of agriculture in developed countries. There is little experience with intercropping of food crops in Western Europe. Yields in intercrops depend on planting patterns of the mixed species in interaction with local growing conditions. Here we present data of two years field experimentation on yield and yield components of a wheat–maize intercrop system in different planting configurations in the Netherlands. Treatments included sole crops of wheat (SW) and maize (SM), a replacement intercrop consisting of strips of six wheat rows alternating with two maize rows (6:2WM), as well as subtractive or additive designs, based on skip-row (6:0WM, 0:2WM) and add-row (8:2WM, 6:3WM) configurations. The land equivalent ratio (LER) of intercrops varied from 1.18 to 1.30 in 2013 and from 0.97 to 1.08 in 2014. Wheat grown in the border rows of wheat strips had higher ear number per meter row, greater kernel number per ear, and greater yield per meter row than wheat in inner rows and sole wheat, indicating reduced competition. Wheat in the border rows in the intercrops had, however, reduced thousand kernel weight and harvest index, indicating that competition in border rows intensified over time. Intercropping negatively affected maize biomass and thousand kernel weight, especially in add-row treatments. This study indicates that there is a potential yield benefit for the wheat–maize intercropping system under Western European growing conditions. However, the LER was affected by yearly variation in weather conditions and significantly greater than one in only one of the two years of the study.  相似文献   

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5.
An overview of the developments of some key technics such as spread frequency communication, adaptive anti-interference and comprehensive anti-jamming technology in anti-jamming communications over the world is shown and discussed. Some suggestions to develop anti-jamming communications are also given in the paper.  相似文献   

6.
《保鲜与加工》1997,(6):116-121
A review on environment-monitoring biosensors is presented.During recent years,various environment-monitoring biosensors are fast developed.They are applied to various areas,such as aquatic environment,atmosphere environment et al.The developing trend of environment_monitoring biosensors is also discussed.  相似文献   

7.
中国已成为继美国之后的全球第二大能源消费国,能源问题已成为制约一个国家经济发展的首要因素之一。目前,中国在解决能源问题方面,所采取的措施尚不能从根本上解决这一问题。提出能源农业的概念,系统阐述了能源农业的特点以及中国在发展能源农业方面所要采取的能源作物的筛选、培育、标准化栽培管理制度的建设、加工设备和加工工艺、能源转化设备转化效率和转化机制以及区域发展规划制定等一系列的基础及基础应用研究措施。  相似文献   

8.
Development and Prospects of Activated Sludge Dynamic Model   总被引:2,自引:0,他引:2  
  相似文献   

9.
This paper introduces a basic concept of network virtual instrument and presents a solving scheme based on the .net framework for web network virtual instrument in which the component technology are used to construct UI component, data-service component, signal-processing component, DB-component, controlling component and data-acquiring component, in accordance to demand these component above can be flexibly put on the right place to realize remote test and control. In the light of the scheme, a set of network oscilloscope based on web is designed to remotely sampling data, and the technology of data base is successfully used to administer the saving and taking of signals in network virtual instrument .  相似文献   

10.
Based on the analysis of the status of building construction in China, the development of Assembled Structure System (ASS) can solve not only the problems in construction, but also is the key for realization of building industrialization. On the basis of technique innovations, a study on the structural performance, construction method and precast production of ASS should be carried out to inherit the old one and overcome its demerits. The process reengineering should be done in the construction enterprise to promote the development of building industrialization.  相似文献   

11.
Development and Build of Green Ecological Residential Guarter   总被引:1,自引:0,他引:1  
This paper, from the perspective of green ecological construction, discusses the development tendency of green ecological residential quarter, analyses the cause, implication, characteristics and practical functions of green ecological residential quarter. And it proposes some suggestions of developing and constructing green ecological residential quarter with green design, wholesale afforestation, green building materials, energy saving and water saving, green lighting, classified garbage disposal and so on. The paper then raises some new suggestions about the programme and design of green ecological residential quarter.  相似文献   

12.
Analysis and forecast for market have become important methods of making decision in most enterprises. It is the base of analysis and forecast to effectively store and make full use of the data in the distribution. Technology of data warehouse and OLAP provides the strong function of storing and integrating data, and mathematics methods provides a series of statistics and analysis tools. Combine IT and mathematics methods in the field of analysis and forecast for the data of distribution to put forward a design and implementation plan of application system in supporting decision based on data warehouse. The design exhibits the processes how to build data warehouse and multi-dimensional data, recommends the methods of analyzing and forecasting, and shows a good integration of advanced information technology and decision science.  相似文献   

13.
How plants survive and adapt to microgravity environments is highlight problem in space biology. Research progress on influences of microgravity and simulated micrograviy on plant growth and development is reviewed. The advance in studies on physiological and biochemical characteristic changes in microgravity or simulated microgravity environments is specially discussed. Experment evidence shows that calcium concentration and distribution changed under microgravity stimulate and then Ca2+ as a second message in transmission related enzyme activity. It is pointed out that further researches should focus on difference express of involved genes and mechanism and applications in such fields as germination of aging seed , accumulation of secondary metabolite and protoplasm fusion under microgravity environments.  相似文献   

14.
Cotton (Gossypium hirsutum L.) is the leading cash crop being grown across the globe including Pakistan. By the inclusion of insect resistant transgenic cotton (BT cotton), the cotton production has mounted many folds in Pakistan. BT cotton is mostly grown in Southern Punjab in cottonwheat cropping system of Pakistan; however there exists a time conflict among wheat harvest and BT cotton sowing in this system. Wheat is harvested during late April but the ideal sowing time of BT cotton is early-mid March indicating a time conflict of 46 weeks which is becoming the main concern leading to wheat exclusion from this system. Intercropping of BT cotton in standing wheat is one of the possible options to manage this overlapping period. This two year field study was, therefore, conducted at two locations (Multan, Vehari) to evaluate the economic feasibility of relay intercropping of BT cotton through different sowing methods in BT cottonwheat cropping system. BT cottonwheat cropping systems included in the study were: conventionally tilled cotton (CTC) on fallow land during early and late March, CTC during late April after harvest of flat sown wheat (FSW), bed sown wheat (BSW) + intercropped cotton during early and late March, and ridge sown wheat (RSW) + intercropped cotton during early and late March. Planting cotton in fallow land with conventional tillage during early March had more seed cotton yield; whereas planting in the same way during April after wheat harvest had minimum seed cotton yield. Likewise, FSW had more yield than ridge and bed sown wheat with intercropped BT cotton during early or late March. However, the system productivity in terms of net income, benefit: cost ratio and marginal rate of return of BSW + intercropped BT cotton during early March was the highest during both years at both locations. However, the system with sole crop of BT cotton sown on fallow land during late or early March was the least economical even than the system with CTC during late April after harvest of FSW. In conclusion, BSW + intercropped cotton during early March may be opted to manage the time conflict and improve the economic productivity of BT cottonwheat cropping system without wheat exclusion from the system.  相似文献   

15.
Aiming at the problems of ABS products tested on vehicle, a character test-bed of automobile and motorcycle ABS is studied.To provide an economic and efficient test method for vehicle anti-lock braking system(ABS) in laboratory,the idea of designing a dynamic test-bed is researched and developed,which can simulate actual working status of automobiles well and truly.The test-bed structure character,design principle and key techniques are discussed.It will provide a new method for testing ABS products of automobile and motorcycle.  相似文献   

16.
Advances in Research and Development of the Botanical fungicide   总被引:15,自引:0,他引:15  
概述了目前植物源杀菌剂植物资源、有效成分、构效关系、作用机理的研究现状。总体来讲,在具有抗菌活性植物资源筛选方面已经做了大量工作,但大多停留在植物初提物;有效成分的分离纯化、构效关系及作用机理的研究较少有待进一步深入。  相似文献   

17.
18.
The goals of our cotton research program are tounderstand fiber developmental biology andimprove fiber production using molecular andgenomic tools.In the genome mapping project,we have developed a cotton genetic map using amoderate set of AFLP,SSR,and RFLP  相似文献   

19.
20.
Crosses between hexaploid wheat and rye can only succeed when pre- and post-zygotic barriers have been overcome. A rye gene determining embryo lethality (Eml-R1), which is involved in post-zygotic isolation, has been mapped to chromosome 6R. In the present paper the mode of inheritance of Eml-R1 was studied by employing a wheat/rye chromosome 6R addition line. We show that Eml-R1 exists in at least two alternative forms, with the mutant allele Eml-R1b being dominant with respect to wild-type Eml-R1a. Furthermore, we have exploited nulli-tetrasomic lines of wheat to detect a complementary wheat gene present on chromosome 6A. This gene has been designated Eml-A1.  相似文献   

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