ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00576.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00577.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Modern agricultural technology and the introduction of new high‐yielding varieties are largely eliminating the wide range of crop genetic diversity that has evolved during the five to ten thousand years since food plants were first domesticated. Related wild species are also on the decline because of new land use policies. These gene pools (or what is left of them) are generally spoken of as genetic resources, and are vitally needed in the creation of new crop varieties by plant breeders. Wild species and land races often furnish genes conferring resistance to diseases and pests and adaptation to environmental stresses which cannot be found in the modern crop varieties.The study of genetic diversity of crops, its storage in gene banks or in natural reserves, its evaluation and enhancement, are briefly described. The genetic resources work of the Food and Agriculture Organisation of the United Nations (FAO) and other international agencies such as the International Board for Plant Genetic Resources (IBPGR) is outline

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00578.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

There has been a concerted world effort to explore, collect and conserve the genetic diversity of our crops and their wild relatives. To attain these objectives carefully planned expeditions are needed. The collecting team, the route and the timing of an expedition are discussed here. In particular, the collecting strategy, based on population sampling, the nature of the material, whether seeds (orthodox or recalcitrant) or vegetative material, and methods of storage during the expedition, arc of exceptional importance. Documentation of samples is also of particular importance as part of the overall strategy in germplasm exploration.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00579.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The safest and most economical and convenient way of preserving the genetic resources of the majority of crop plants is by long‐term seed storage. The technology is well developed, but recent research resulting from a greater understanding of behaviour at very low water potentials is leading to further improvemen

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00580.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

In‐vitro (tissue culture) techniques offer ways of overcoming serious problems in the conservation of crop genetic resources. These primarily involve the use of slow growth and cryopreservation in liquid nitrogen to store germplasm, but there are also important applications in other areas, including germplasm collecting, multiplication and exchange. Slow growth techniques for medium‐term storage of cultures are relatively well developed and in‐vitro active gene bank establishment is feasible. Cryopreservation for long‐term storage is possible for some materials but, in general, requires further research and development. Among the aspects to be examined are the behaviour of different culture systems when exposed to ultralow temperatures, crop‐specific requirements and the genetic stability of stored

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00581.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The dramatic increase in yields of agricultural crops over the last 40 years in developed countries has been attributed equally to improved genetic components and improved agronomic practices. Thesuccessof plant breeding is based partly on an increased understanding of the parameters involved, to a great extent on improved and more efficient methods of selection, to greater use of available genetic diversity and also to advances in a number of related disciplines including plant pathology, biochemistry, agronomy and genetics. Successes and problems associated with using various genetic resources in plant breeding are illustrated with examples from some of the world's major crops, including potatoes, barley and cotton.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00582.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A description is given of the Nordic Gene Bank for Agricultural and Horticultural Plants (NGB), its origins, its mandate, its organization, the scientific concepts it has adopted as a base for its activities and some of the work done during the first ten years. The new project in the South African Development Coordination Conference (SADCC) countries to establish a regional gene bank is also outlined. In both cases the aims are the improvement of crop varieties through the use of local and international genetic resources materials.The mandate of the NGB covers preservation and documentation of the genetic variation of Nordic agricultural and horticultural plants as a service institution for plant breeding and other plant research. NGB is located at Alnarp, Sweden, and is governed by a Board consisting of two members from each of the five Nordic countries, Denmark, Finland, Iceland, Norway and Sweden. The SADCC Regional Gene Bank (SRGB) is a project of the governments of the SADCC member states: Angola, Botswana, Lesotho, Malawi, Mozambique, Namibia, Swaziland, Tanzania, Zambia and Zimbabwe. The primary objective is to establish, over a 20‐year period, a Regional Plant Genetic Resources Centre to preserve, evaluate and utilize through breeding the indigenous plant genetic resources material and natural crop heritage of the region.The project is a crucial component in implementing the broader 20‐year regional programme of agricultural research, already agreed by the SADCC countries, to increase per capita agricultural output; this programme is expected to lead to a rapid improvement in cultivated plant varieties throughout the region. An essential element of the project is the training and education of plant genetic resources person

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00583.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The awareness of the importance of plant biodiversity has been considerably raised in both developed and developing countries over the last decade. Some of the debate has not been helpful in fostering collaboration or progress towards a more rational support network. The paper attempts to identify and categorize existing efforts in operation in a wide range of institutions and bodies ranging from essentially environmentally orientated to crop‐based organizations. Current funding and training initiatives are discusse

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00584.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The techniques of molecular biology will become a standard part of germplasm conservation and exploitation. They are being used to gather information very rapidly about chromosome structure and genetic variation within the major crop species. Genetic maps with hundreds of DNA sequence markers covering the whole genome have already been created for some crops, such as maize, soybean, wheat and potato. Genetic variation is being revealed by the combined use of restriction endonucleases, fractionation of DNA fragments by electrophoresis and investigation of the size of specific allelic fragments. This kind of approach offers new opportunities to assess the extent of genetic variation among accessions in germplasm collections, thereby helping to decide which accessions are essentially duplicates and which should be maintained in a core collection. I recommend that germplasm banks will in the future also contain diagnostic DNA markers for characterizing and screening germplasm.When material from germplasm banks is used in crop plant breeding programmes to transfer specific traits into the crop, the availability of a complete set of molecular markers covering the entire genome makes it straightforward to discover which segments have been transferred and which are essential to maintain, so as to preserve the introduced trait.Germplasm banks are obviously a source of new genetic variation for the molecular geneticist as well as the plant breeder. The isolation of specific alleles determining self‐incompatibility fromBrassica oleraceaaccessions for subsequent introduction into oil seed rape is described as an exampl

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00585.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY