Plant Breeding Methods Research Articles

A survey of yield differences between transgenic and non-transgenic crops

In the current survey, there was no clear evidence that GM (genetically modified) crops are higher yielding than those conventionally bred<fnoteref rid="fn1">1</fnoteref>. Furthermore, there were no trials to support valid comparisons of yield per se. This article investigates GM crop yields, introducing the importance of hybrid vigour and a non-stress environment for higher percentage heritability selection and therefore more productive conventional plant breeding and improved crops. GM technology and crops are compared with proven plant breeding methods, with respect to hybrid vigour and the economic viability of both systems. These proven methods of plant breeding are (1) traditional landrace cropping, (2) conventional Mendelian breeding and (3) Isolection Mendelian breeding, and are also considered historically.

Future directions of the Bean/Cowpea Collaborative Research Support Program

The Bean/Cowpea Collaborative Research Support Program (CRSP) has provided an opportunity for experienced US scientists to become involved in international research and development in a way that also has benefited their research for the USA. The comparative advantage of the CRSP is in plant breeding, but with a broad interdisciplinary approach that also develops compatible management and processing methods, thereby enhancing system sustainability, food quality and marketing opportunities for beans and cowpeas. The CRSP should continue to make uniquely important contributions to bean and cowpea cultivar development. In addition, it should give some emphasis to up-stream research, such as the development of improved technologies for indirect DNA-marker-assisted selection (MAS) that could lead to improved plant breeding methods. A careful approach to the development of transgenic lines is recommended that is limited to transferring important genes not currently present in the species into cowpea and possibly bean germplasm, for example those that confer resistance to specific major insect pests of cowpea. The CRSP should continue to play a major role in graduate education, and could take advantage of distance learning via the internet to enhance collaboration in education and research among universities in developing countries and the USA. CRSP scientists can and should play a key role in enhancing mutual understanding and collaboration on an international scale because this could make major contributions to world peace.

Prospects of Breeding Quinoa for Tolerance to Abiotic Stress

Aspects related to the breeding of quinoa for increased tolerance against frost, drought, and salinity are presented with special emphasis on the conditions existing in the Peruvian Andes. Evidence from the literature indicates that plants' responses to these stresses are essentially similar, and the physiological processes involved are interrelated. The evidence suggests that tolerance to abiotic stress is polygenicallyinherited, justifying the application of appropriate plant breeding methods. A compilation of meteorological studies is presented that can be used to define the specific climatic phenomena of night frosts occurring in the quinoa-growing region of the Andes and to specify the conditions for selection of tolerant varieties. A composite-bulk breeding scheme is proposed that could be useful for highly efficient breeding of quinoa varieties. Possible future application of molecular-marker-assisted selection is discussed.

Grapevine genetic engineering: tool for genome analysis or plant breeding method? Which future for transgenic vines?

Abstract Though the production of transgenic grapevines for commercial release is not conceivable for another ten or fifteen years, the current interest focused on public hostility against food products from genetically modified plants has led to a slowdown in research on grapevine transformation, at least in European grape-growing countries. The usefulness of transgenic grapevine cultivars is questioned, in spite of the benefits for health and environment that could be derived through the reduced use of chemical sprays to protect grapevines genetically modified for higher resistance to or tolerance of pathogens. However, grapevine transformation is a valuable tool to understand the genetics and mechanisms of plant growth, development and metabolism. Thus, the availability of improved and efficient techniques of transformation is needed to sustain the current development of grapevine genomics.

The impact of participatory plant breeding (PPB) on landrace diversity: A case study for high-altitude rice in Nepal

Participatory plant breeding (PPB) methods were used to develop two farmer-accepted, cold-tolerant rice varieties in Nepal — Machhapuchhre-3 (M-3) and Machhapuchhre-9 (M-9). Both were derived from the cross Fuji 102/Chhomrong Dhan. Following the introduction of these varieties, the changes in the rice landraces and varieties that farmers grew were studied in ten villages. In seven of them for which data were analysed for both 1996 and 1999, adopting farmers grew 18 landraces and four modern varieties of which three, M-3, M-9 and Lumle-2, were the products of PPB. These three varieties covered 10% of the total rice area and 33% of the rice area of the adopting farmers in the seven study villages in the 1999 survey. The adoption of the PPB varieties impacted most on the more commonly grown landraces. With the exception of two villages, the varietal richness among adopting farmers was either static or increased, and there was an overall increase in allelic diversity. However, in future, the increasing adoption of M-3 and M-9 could result in significant reductions in varietal richness, although, allelic diversity may not be greatly reduced.

Clinical risk assessment of GM foods

The main concerns about adverse effects of genetically modified (GM) foods on health are the transfer of antibiotic resistance, toxicity and allergenicity. There are two issues from an allergic standpoint. First, the transfer of a known allergen may occur from a crop into a non-allergenic target crop. The second scenario is the creation of a neo-allergen where de novo sensitisation occurs in the population. The first scenario occurred in 1996 when the 2S albumen protein from Brazil nut was transferred into soy bean (N. Engl. J. Med. 334 (1996) 688). 2S albumen was found to be a major Brazil nut allergen and the newly expressed protein in transgenic soy retained its allergenicity. Patients allergic to Brazil nuts and not to soy bean now showed an IgE mediated response towards GM soy bean. We argue that it is possible to prevent such occurrences by doing IgE-binding studies and taking into account physico-chemical characteristics of proteins and referring to known allergen databases. The second possible scenario of de novo sensitisation does not easily lend itself to risk assessment. We compare GM technology to traditional plant breeding and food processing methods. There is no evidence that the technology used for the production of GM foods poses an allergic threat per se compared to other methodologies widely accepted in the food industry. We need to proceed cautiously in the future, assessing individual GM foods on the basis of their individual merits and risks prior to introducing them into the market.

Introduction to the Special Issues on Plant GM Technology

Introduction to the Special Issues on Plant GM Technology

Identification of a microsatellite on chromosomes 6B and a STS on 7D of bread wheat showing an association with preharvest sprouting tolerance

In bread wheat, the transfer of tolerance to preharvest sprouting (PHS) that is associated with genotypes having red kernel colour to genotypes with amber kernels is difficult using conventional methods of plant breeding. The study here was undertaken to identify DNA markers linked with tolerance to PHS as these would allow indirect marker-assisted selection of PHS-tolerant genotypes with amber kernels. For this purpose, a set of 100 recombinant inbred lines (RILs) was developed using a cross between a PHS-tolerant genotype, SPR8198, with red kernels and a PHS-susceptible cultivar, ‘HD2329’, with white kernels. The two parents were analysed with 232 STMS (sequence-tagged microsatellite site) and 138 STS (sequence-tagged site) primer pairs. A total of 300 (167 STMSs and 133 STSs) primer pairs proved functional by giving scorable PCR products. Of these, 57 (34%) STMS and 30 (23%) STS primer pairs detected reproducible polymorphism between the parent genotypes. Using these primer pairs, we carried out bulked segregant analysis on two bulked DNAs, one obtained by pooling DNA from 5 PHS-tolerant RILs and the other similarly derived by pooling DNA from 5 PHS-susceptible RILs. Two molecular markers, 1 STMS primer pair for the locus wmc104 anda STS primer pair for the locus MST101, showed apparent linkage with tolerance to PHS. This was confirmed following selective genotyping of individual RILs included in the bulks. Chi-square contingency tests for independence were conducted on the cosegregation data collected on 100 RILs involving each of the two molecular markers (wmc104 and MST101) and PHS. The tests revealed a strong association between each of the markers and tolerance to PHS. Using nullisomic-tetrasomic lines, we were able to assign wmc104 and MST101 to chromosomes 6B and 7D, respectively. The results also indicated that the tolerance to PHS in SPR8198 is perhaps governed by two genes (linked with two molecular markers) exhibiting complementary interaction.

Transgenic organisms: should we use them or not?: Transgenic Organisms: Biological and Social Implications. Edited by J. Tomiuk, K. Wöhrmann and A. Sentker. Birkhauser, Basel. 1996. Price sFr. 88,-/DM 108. ISBN 3-7643-5262-0.

The production and use of transgenic organisms is controversial in western societies, and has been actively debated by various groups and in various media ever since the potential risks involved in producing transgenic organisms were first brought to general attention by a group of scientists in the early 1970s. Today it is mainly the concern of the general (consumer) public that slows down the speed of widespread introduction of transgenes in society. Meanwhile, the technical development in the scientific community and in the R & D groups of large companies proceeds rapidly, as witnessed by the regular hot news items that sweep through the public media. As usual with developments that on the one hand promise interesting economic gains for some and on the other hand have or seem to have a large impact on our society or on nature, risk assessment studies and certainly the ethical discussion tend to lag behind. One of the prerequisites for proper risk assessments as well as for a successful ethical discussion is the availability of good information. This book is meant as a contribution to the field by providing an overview of the state of the art with respect to biological and social phenomena related to the use of transgenic organisms. The book results from a meeting of scientists in 1995 in Germany and is one in a series, as is explained in one of the chapters written by the editors, where the history and progress in the study of risk assessment is discussed. A remarkable feature of the book that struck me when glancing over the contents pages is that all chapters have either a German (co)author or an author working in a German-speaking country, but this appears not to affect the general value of the book. It only shows that the topic is relatively hot in that part of Europe. Most chapters deal with the biological side. Fundamental molecular–genetic aspects are addressed in chapters on gene-silencing as a mechanism behind the often encountered instability of transgene expression, and on transposable elements as possible mechanisms of horizontal gene transmission. Mechanisms of horizontal transfer are considered further in separate chapters on the situation in bacteria (among themselves) and insects (via baculo viruses). Oddly placed between the chapters on bacteria and insects is a chapter on transgenic crop plants, which unfortunately is little more than a student course in theoretical population genetics. A similar limitation holds for a chapter on effects of transgenes on coevolutionary processes: the general set-up brings little news for the average JEB reader. Informative with respect to risk assessment aspects are the chapters on biological containment of bacteria and on possibilities for monitoring their presence in the soil, as well as a chapter on plants that uses the Weed Beet example to illustrate both the strength and the weakness of current biosafety research. Most chapters end with pointing out factors that need to be taken into account in future research. In the last part of the book attention shifts towards aspects of human health, economics and public opinion. Classical and modern plant breeding methods are compared from the point of view of the breeder, with the conclusion that they are complementary. Introduction of genetically modified food is discussed from a historical and procedural perspective. The state of the art in the HUman GenOme project is described and discussed with respect to its usefulness to human health care. Finally, the role of the media in shaping public opinion and ethical aspects is discussed. Although the chapter on ethical aspects calls for making explicit one’s assumptions and premises when discussing what to allow and what not, the book as a whole gave me no stimulus to develop my own ethical point of view. The atmosphere in the book is either scientifically neutral or implicitly positive towards the new technology. The significance of the book is not so much to inspire one to develop an individual point of view on the matter (although to my mind this is very important to do), but to provide a factual basis of knowledge. Most chapters give a good description of their respective fields, and together they cover many relevant aspects of the introduction of transgenic organisms in society. As such, the book is informative for someone who wants an introduction into the field of facts surrounding transgenic organisms.

CO 2 mitigation cost : Bioenergy systems and natural gas systems with decarbonization

In Sweden today, power production with bioenergy systems is more costly than with fossil energy systems. New technology under development, such as integrated gasification and combined cycle technology (IGCC), and reduced biomass costs would improve the competitiveness of bioenergy systems. The CO 2 mitigation costs are lower for biomass systems using IGCC technology than for natural gas systems using decarbonization. Considering the temporary reduced greenhouse gases from the soil when short-rotation forest ( Salix) replaces annual food crops on mineral soils, the CO 2 mitigation costs could be reduced further by about 10% for bioenergy systems. The cost of Salix can be reduced in the future by about 30% because of improvements in plant breeding and cultivation methods, and even more if Salix plantations are used for the treatment of municipal waste water. This would further improve the competitiveness of bioenergy systems. Several data used in the cost calculations are uncertain, especially regarding new technologies such as IGCC, decarbonization, and waste water treatment in Salix plantations, and will vary with local conditions. The results are, however, most sensitive to changes in the fuel costs and particularly so in the case of natural gas systems.

Foliar calcium concentration of potato and its relation to genotype lateness and tolerance of cyst nematodes

In field trials during three years respectively 18, 22 and 57 potato genotypes were grown on soils moderately or heavily infested with potato cyst nematodes (Globodera pallida) after soils were fumigated or not. Nematode infection increased leaf calcium contents but genotypes that were relatively tolerant of potato cyst nematodes (Globodera pallida) had lower leaf calcium concentrations on a particular sampling date. Tolerance of potato cyst nematodes was closely linked to genotype lateness and may be related to tolerance of drought. When using the method in plant breeding and screening for genotypes with tolerance, plants may be planted in infected or in uninfected soils, without influencing the outcome. The relationship between tolerance and calcium contents was clearest when sampling took place towards the end of the growing season when the variability was at it highest with a good distinction between newly formed leaves in late maturing genotypes and aged leaves in early maturing cultivars.

Plant Proteins: Engineering for Improved Quality

Plant protein is the primary source of all dietary protein for humans and livestock. In 1992, world protein production was 137 million metric tons, of which 65% was obtained from plants directly and 35% through animal protein production.' In comparison to meat protein, plant protein is more economic to produce and convenient to transport and store. However, when used as a source of dietary protein for human and monogastric animals, most plant proteins are nutritionally incomplete because of their deficiency in certain essential amino acids. In general, cereal proteins are low in lysine (Lys) and tryptophan (Trp), and legume and most vegetable proteins are deficient in the sulfur amino acids methionine (Met) and cysteine (CYS).~ Amino acid deficiencies can be corrected in at least three ways, namely, supplementation with synthetic amino acids, supplementation with small amounts of protein which are a rich source of the deficient amino acid(s), or complementation with other protein(s) so that the combined protein sources will balance each other's deficiencies or excesses. The American animal feed industry annually spends 150 and 70 million dollars on synthetic Met and Lys, respectively, to supplement the protein base feeds. Conventional plant breeding methods have made some progress in identifying mutations with improved seed protein quality, such as high-Lys corn and barley.3 However, the undesirable traits associated with these mutations, such as lower yields and greater susceptibility to pests and diseases, have prevented their agronomic uti l i~ation.~ Because of a lack of genetic variability in Met content, efforts to breed legumes with increased levels of Met have not had significant success. Recent advances in biotechnology offer alternative approaches to improving the nutritional quality of plant proteins. These include sequence modifications, synthetic genes, overexpression of homologous genes, and transfer and expression of heterologous genes. Progress in this area of research and development was reviewed r e ~ e n t l y . ~ , ~

The ALFALFA CATALOG Software Package

AbstractDue to modern plant breeding methods, agricultural producers have many cultivars available for many different species. Consequently, it is often difficult to recommend a cultivar for a particular growing area. A list of alfalfa cultivars, germplasms, and breeding lines available was published. However, due to the large number of entries in these publications finding pertinent information about a cultivar, breeding line, or germplasm was tedious. The objectives of this project were to (i) develop a computer program to access the alfalfa information in the original database, and (ii) update the database to include those alfalfa cultivars, breeding lines, and germplasms released through late 1992. A computer program was written using Microsoft QuickBasic, ver. 4.5. The original alfalfa database was converted to ASCII format. The resulting software package is entitled the ALFALFA CATALOG ver. 1.0. Three program files and four data files comprise the ALFALFA CATALOG software package. Users may rapidly search the database and retrieve entries by cultivar name, experimental designation, or germ‐plasm. We also wrote a routine to print a list of all cultivars or germplasms that have a specific combination of traits. These search capabilities will allow plant breeders, extension agents, and consultants rapid access to pertinent alfalfa data. Currently, the ALFALFA CATALOG has 752 entries for cultivars and breeding lines, and 144 entries for germplasms. The database will be updated yearly. In its present form, the ALFALFA CATALOG is probably the most complete compilation of alfalfa cultivars, breeding lines, and germplasms available.

Plant genetics: out with the old, in with the new?

Plant breeding represents an evolving technology based largely on genetic principles. Approximately one-half of the increased yields of major crop plants can be attributed to the genetic improvement of the crop. Although the breeding technology and undergirding science are sound, additional information on the biochemical pathways underlying agronomic and quality traits and their genetic control would allow new genetic technologies to be used more fully. Current developments in molecular biology, plant cell and tissue culture, genetic engineering, and use of molecular genetics will facilitate the selection of complex traits. Genetic improvement of plants in the future will be based on an integration of modern plant-breeding methods and the new genetic technologies. Thus, the new genetic approaches do not represent a replacement technology but will add to the arsenal of tools available for improving crops.

IMPUTING CHARACTERISTIC VALUES OF AGRICULTURAL "SEED-STOCK"

Statistical methods of regression and mathematical (linear) programming are employed to combine principles of economics and genetics in a conceptual, multi-step, model of valuation for biotechnical change. The resulting model has the capacity to estimate the value of changes in specific characteristics for specific production environments, whether those changes are accomplished by traditional plant and animal breeding methods or by genetic engineering. The application of the model is illustrated with an example of commercial cow-calf production under conditions typical of the Texas Panhandle using a total of 32 breed groups.

Regeneration from protoplasts-a supplementary literature review

Protoplast technology is important in, on the one hand, the application of various cellular methods in plant breeding (i.e. somatic hybridization, cybridization, direct DNA transfer via polyethylene glycol (PEG), electroporation, micro-injection), and various fundamental studies (e.g. on membrane transport, cell compartmentation, the cytoskeleton in relation to the cell cycle and cell division) on the other hand. For practical applications, plant regeneration from protoplasts is a prerequisite. In 1989, regeneration from protoplasts was listed (Roest & Gilissen 1989) for 214 higher plant species (Spermatophyta), representing 97 genera and 31 families. Since then, regeneration procedures for more than 100 higher plant species have been reported. These include many economically important agricultural and horticultural crops, as well as woody plant species. In this paper these new species are listed, supplemented with specific information on the donor tissue used, the culture technique applied, and the type of development of the regenerants. In addition, recent achievements in fundamental aspects of protoplast research, which gradually provide further insight into the genetical, physiological and ultrastructural background of the phenomenon of totipotency of plant cells, will be briefly reviewed.

Breeding tall fescue for establishment vigour

Tall fescue (Festuca arundinacea Schreb.) has been shown to have great potential to supply quality forage through the summer in environments where the water regime limits performance of perennial ryegrass (Loliumperenne L.). The use of tall fescue seed in NZ has risen from almost none 15 years ago to about 200 tonnes today. However the further use of tall fescue is limited by the difficulty some farmers have in establishing it, particularly when performance is compared with perennial ryegrass. Experience is generally that the widely used imported cultivar AU Triumph establishes more vigorously than the NZ cultivar Grasslands Roa. Tall fescue breeding at AgResearch Grasslands has in the past 10 years concentrated on improving the vigour at establishment, while maintaining the excellent standard of forage quality achieved with Roa. Data are presented indicating substantial progress, with breeding line families outperforming all control cultivars. However, further data suggest a strong effect of conditions of seed ripening and harvest on the vigour of seed when sown. Data comparing different field multiplications and comparing breeding families harvested in the field and in the glasshouse confirm this. Field sowings and more controlled nursery box experiments are described. The paper discusses implications for plant breeding method and for seed production

Genetics and conservation

The basic sciences of genetics and ecology have long played a vital role in agriculture. New technologies spawning a gene revolution promise to revolutionize agricultural genetics. The opportunities to utilize these new techniques, along with standard methods of animal and plant breeding, are great for agriculture, conservation biology, and their synergism. Biological diversity is inextricably linked to human welfare. Genetic engineering is viewed as having both promise and risk to agricultural and natural biological systems, suggesting that its application must be evaluated on a case-by-case basis. In order to adequately manage genetic resources, patterns of genetic variation must be documented and their relationship to the life-histories of species and the functioning of ecosystems understood. To achieve this goal, species to receive attention must be prioritized, possibly based on their usefulness as indicator species in defining genetic management strategies for biological groups of species. Particular attention should be given to invasive species, to the phenotypic plasticity of species, and the organizational complexity of populations, communities, and ecosystems. A return to greater scientific emphasis at the organismal and ecosystem level obviously is essential.

Book Review: Advanced Methods in Plant Breeding and Biotechnology.

Book Review: Advanced Methods in Plant Breeding and Biotechnology.

Biotechnology and plant breeding: relevance of cell genetics in potato improvement

SynopsisThe adoption of emerging biotechnological methods in plant breeding is presented discussing specifically the relevance of cell genetics to potato improvement. The finding and use of efficient anther plant producing strains of potato (EAPP clones) is first discussed. This is followed by the presentation of recent progress toward the obtaining of diploid potato strains producing a high percentage of monohaploids from anthers. The selection of homozygous diploid regenerants (potato ‘pure lines’) by using an RFLP approach is also presented. A summary chart is presented, containing the description of an integrated breeding procedure that may be considered for future breeding of this species.