Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Plant Breeding”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed2006

Mixed-model QTL mapping for kernel hardness and dough strength in bread wheat.

Plant breeding data comprise unbalanced phenotypic data for inbreds with complex pedigrees. As traditional methods to map quantitative trait loci (QTL) cannot exploit plant breeding data, an alternative approach is QTL mapping via a mixed-model procedure. Our objective was to validate mixed-model QTL mapping for self-pollinated crops by detecting QTL for kernel hardness and dough strength from data in a bread wheat (Triticum aestivum L.) breeding program. We studied 80 parental and 373 experimental inbreds genotyped for 65 simple sequence repeat (SSR) markers and three candidate loci. The methodology involved three steps: variance component estimation, single-marker analyses, and a final multiple-marker analysis with marker effects treated as fixed effects. Two QTLs for kernel hardness were detected on chromosomes 1A (close to candidate locus GluA3) and 5D (close to candidate locus Ha). Four QTLs were detected for dough strength on chromosomes 1A, 1B, 1D, and 5B. Candidate gene GluA1, which was associated with dough strength, was the only candidate locus found significant. Results were consistent with previously reported markers and QTLs associated with kernel hardness and dough strength. Unlike previous studies that have assumed QTL effects as random, the assumption of fixed marker effects identified the favorable marker alleles to select for. We conclude that the detection of previously mapped QTL validates the usefulness of mixed-model QTL mapping in the context of a plant-breeding program.

Alleles↗
PubMed2001

Influence of genetic background and heterozygosity on meiotic recombination in Arabidopsis thaliana.

Plant breeding relies on genetic variability generated by meiotic recombination. Control of recombination frequencies is not yet possible, but would significantly extend the options for plant-breeding strategies. A prerequisite would be variability of recombination frequencies. In this study, 15 transgenic kanamycin (KR) and hygromycin (HR) resistance gene insertions mapping to the five Arabidopsis thaliana chromosomes were used as genetic markers. Recombination frequencies were determined from the frequencies of resistance phenotypes within populations segregating for linked KR and HR markers. Recombination frequencies of marker pairs were compared among these four ecotypes, among F1s in both reciprocal forms derived from these ecotypes, and between F1s and their parent lines. On average, the recombination frequencies in F1 crosses were substantially higher (up to 2-fold) than in the homozygous parental ecotypes. A strong negative correlation between genetic similarities of ecotypes and recombination frequencies was detected for two adjacent marker pairs located on the long arm of chromosome 3, but not for marker pairs in other genomic regions. Our results suggest that heterozygosity influences recombination in plant breeding, and cannot be ignored in genetic mapping of genomes.

Arabidopsis↗
PubMed2026

From feasibility to predictability: prime editing redefines precision breeding in plants.

Originally developed in mammalian systems as a genome editing strategy without double-strand breaks, prime editing (PE) has been adapted for precise genome modifications. However, its deployment revealed key limitations, including reduced efficiency, strong locus dependency, low germline transmission, and somatic chimerism. Consequently, diverse PE variants have emerged, resulting in fragmented landscape of architectures with context-dependent and inconsistent performance. This review consolidates these advances and outlines emerging design principles behind plant PE systems. It evaluates optimization strategies at multiple levels, discusses their applications in monocots and eudicots, and highlights persistent bottlenecks and future directions, including AI-guided protein engineering and improved delivery strategies. These advances position PE as a rapidly evolving platform toward enabling precision breeding in plants.

cis-regulatory engineering↗
PubMed2004

Breeding for micronutrients in staple food crops from a human nutrition perspective.

Over three billion people are currently micronutrient (i.e. micronutrient elements and vitamins) malnourished, resulting in egregious societal costs including learning disabilities among children, increased morbidity and mortality rates, lower worker productivity, and high healthcare costs, all factors diminishing human potential, felicity, and national economic development. Nutritional deficiencies (e.g. iron, zinc, vitamin A) account for almost two-thirds of the childhood death worldwide. Most of those afflicted are dependent on staple crops for their sustenance. Importantly, these crops can be enriched (i.e. 'biofortified') with micronutrients using plant breeding and/or transgenic strategies, because micronutrient enrichment traits exist within their genomes that can to used for substantially increasing micronutrient levels in these foods without negatively impacting crop productivity. Furthermore, 'proof of concept' studies have been published using transgenic approaches to biofortify staple crops (e.g. high beta-carotene 'golden rice' grain, high ferritin-Fe rice grain, etc). In addition, micronutrient element enrichment of seeds can increase crop yields when sowed to micronutrient-poor soils, assuring their adoption by farmers. Bioavailability issues must be addressed when employing plant breeding and/or transgenic approaches to reduce micronutrient malnutrition. Enhancing substances (e.g. ascorbic acid, S-containing amino acids, etc) that promote micronutrient bioavailability or decreasing antinutrient substances (e.g. phytate, polyphenolics, etc) that inhibit micronutrient bioavailability, are both options that could be pursued, but the latter approach should be used with caution. The world's agricultural community should adopt plant breeding and other genetic technologies to improve human health, and the world's nutrition and health communities should support these efforts. Sustainable solutions to this enormous global problem of 'hidden hunger' will not come without employing agricultural approaches.

Biological Availability↗
PubMedDate not supplied

The implausibility of Mendel's theory before 1900.

Attention is paid to the category of the plausibility of Mendel's terminology in formulating the research problem, in describing experimental model and research method and in explaining his theory in the historical context of the long lasting enigma of generation, hybridization and heredity. The new research problem of heredity derived from the enigma of generation was plausible for the sheep breeders in Brno in 1836-1837 who also formulated the research question: what and how is inherited? But they did not find an approach to the experimental investigation. Later in 1852 the research problem of heredity was formulated by the physiologist of the Göttingen University, R. Wagner, who also outlined the method of crossing animals or artifical fertilization of plants for the investigation of the enigma of generation and heredity. But he could not carry out the recommended experiments at the University. His proposal remained without echo. Mendel first mentioned the motivation for his research arising from plant breeding experience and then from the experiments with plant crossing by botanists. He delivered his lectures in Brno to the community of naturalists, who paid attention to the appearance of hybrids in nature, but were not interested in plant breeding. After describing research model and experimental method Mendel presented the sequence of hypotheses proved in experiments and explained the origin and development of hybrids and at the same time also the mechanism of fertilization and of transmission of traits, what was heredity without using the term. The listeners of his lectures and later the readers of his paper did not understand his explanation. ...

Austria↗
PubMed1996

Comparative genetic and QTL mapping in sorghum and maize.

DNA markers and genetic maps will be important tools for direct investigations of several facets of crop improvement and will provide vital links between plant breeding and basic plant biology. The markers and maps will become more important for increased crop production because plant genetics will be required to extend or replace extant management practices such as chemical fertilizers, pesticides, and irrigation (Lee, 1995). Despite the importance of the sorghum crop, comprehensive genetic characterization has been limited. Therefore, the primary goal of this research program was to develop basic genetic tools to facilitate research in the genetics and breeding of sorghum. The first phase of this project consisted of constructing a genetic map based on restriction fragment length polymorphisms (RFLPs). The ISU sorghum map was created through linkage analysis of 78 F2 plants of an intraspecific cross between inbred CK60 and accession P1229828 (Pereira et al., 1994). The map consists of 201 loci distributed among 10 linkage groups covering 1,299 cM. Comparison of sorghum and maize RFLP maps on the basis of common sets of DNA probes revealed a high degree of conservation as reflected by homology, copy number, and collinearity. Examples of conserved and rearranged locus orders were observed. The same sorghum population was used to map genetic factors (mutants and QTL) for several traits including vegetative and reproductive morphology, maturity, insect, and disease resistance. This presentation will emphasize analysis of genetic factors affecting plant height, an important character for sorghum adaptation in temperate latitudes for grain production. Four QTL for plant height were identified in a sample of 152 F2 plants (Pereira and Lee, 1995) whereas 6 QTL were detected among their F3 progeny. These observations and assessments of other traits at 4 QTL common to F2 plants and their F3 progeny indicate some of these regions correspond to loci (dw) previously identified on the basis of alleles with highly qualitative effects. Four of the six sorghum plant height QTL seem to be orthologous to plant height QTL in maize. Other possible instances of orthologous QTL included regions for maturity and tillering. These observations suggest that the conservation of the maize and sorghum genomes encompasses sequence homology, collinearity, and function. The genetic information and technology developed on the basis of DNA markers could be used in several facets of breeding, genetics, and other basic biological investigations. In addition, DNA markers have been used to survey large collections of elite sorghum germ plasm to determine the degree of genetic relationships and genetic diversity (Ahnert et al., 1996). RFLP data seem to portray genetic relationships more accurately than the methods based exclusively on the coancestry coefficient. This information provides the basis for more accurate perceptions of genetic relationships and diversity.

Adaptation, Physiological↗
PubMed2003

Plant biotechnology and breeding: allied for years to come.

Plant metabolic engineering is lagging behind other kinds of genetic manipulation of plants. Creating metabolic pathways or improving their yields requires a better understanding of plant metabolism and of its regulation. Metabolic Control Analysis provides an interpretation of experimental failures and a guide for manipulators. It suggests also that there might be intrinsic limits to raising yields in already abundant products. At present, these limits can be dealt with more effectively by plant breeding.

Biotechnology↗
PubMed2007

Patch aging and the S-Allee effect: breeding system effects on the demographic response of plants to habitat fragmentation.

We used empirical and modeling approaches to examine effects of plant breeding systems on demographic responses to habitat fragmentation. Empirically, we investigated effects of local flowering plant density on pollination and of population size on mate availability in a common, self-incompatible purple coneflower, Echinacea angustifolia, growing in fragmented prairie habitat. Pollination and recruitment increased with weighted local density around individual flowering plants. This positive density dependence is an Allee effect. In addition, mean mate compatibility between pairs of plants increased with population size. Based on this empirical study, we developed an individual-based, spatially explicit demographic model that incorporates autosomal loci and an S locus. We simulated habitat fragmentation in populations identical except for their breeding system, self-incompatible (SI) or self-compatible (SC). Both populations suffered reduced reproduction in small patches because of scarcity of plants within pollination distance (potential mates) and inbreeding depression. But SI species experienced an additional, genetic contribution to the Allee effect (S-Allee effect) caused by allele loss at the S locus, which reduces mate availability, thereby decreasing reproduction. The strength of the S-Allee effect increases through time (i.e., patches age) because random genetic drift reduces S-allele richness. We investigate how patch aging influences extinction and discuss how the S-Allee effect influences communities in fragmented habitat.

Breeding↗
PubMed2000

Transgenic hairy roots. recent trends and applications.

Agrobacterium rhizogenes causes hairy root disease in plants. The neoplastic roots produced by A. rhizogenes infection is characterized by high growth rate and genetic stability. These genetically transformed root cultures can produce higher levels of secondary metabolites or amounts comparable to that of intact plants. Hairy root cultures offer promise for production of valuable secondary metabolites in many plants. The main constraint for commercial exploitation of hairy root cultures is their scaling up, as there is a need for developing a specially designed bioreactor that permits the growth of interconnected tissues unevenly distributed throughout the vessel. Rheological characteristics of heterogeneous system should also be taken into consideration during mass scale culturing of hairy roots. Development of bioreactor models for hairy root cultures is still a recent phenomenon. It is also necessary to develop computer-aided models for different parameters such as oxygen consumption and excretion of product to the medium. Further, transformed roots are able to regenerate genetically stable plants as transgenics or clones. This property of rapid growth and high plantlet regeneration frequency allows clonal propagation of elite plants. In addition, the altered phenotype of hairy root regenerants (hairy root syndrome) is useful in plant breeding programs with plants of ornamental interest. In vitro transformation and regeneration from hairy roots facilitates application of biotechnology to tree species. The ability to manipulate trees at a cellular and molecular level shows great potential for clonal propagation and genetic improvement. Transgenic root system offers tremendous potential for introducing additional genes along with the Ri T-DNA genes for alteration of metabolic pathways and production of useful metabolites or compounds of interest. This article discusses various applications and perspectives of hairy root cultures and the recent progress achieved with respect to transformation of plants using A. rhizogenes.

Journal Article↗
PubMed2002

Transgenic, transplastomic and other genetically modified plants: a Canadian perspective.

Since the mid 1990s, genetically modified (GM) crops have been grown commercially in Canada on a scale that has increased steadily over the years. An intense debate ensued, as elsewhere, and many fears were expressed regarding not only the technology itself but some of the main GM crops being grown. It would seem appropriate at this time to examine how these novel crops compare to crops bred by more traditional means and what impacts these GM crops have had based on experience and not merely on conjecture. To begin, we will put things in a historical perspective and recall how domestication and conventional plant breeding have shaped the crops of today. Then, we will describe briefly the distinctive features of GM plants (obtained so far mainly by nuclear transgenesis) and how these novel crops are regulated in Canada. We will then give two examples of widely grown GM crops in Canada (insect-resistant corn and herbicide-tolerant canola) and examine the main questions that were raised as well as the actual impacts these crops have had on the farm. These examples will help us outline some of the limitations of the current generation of GM plants and, finally, we will try to get a glimpse of the future by examining some recent technical developments in the field of recombinant DNA technologies applied to plant breeding.

Agriculture↗
PubMed2005

Iron-biofortified rice improves the iron stores of nonanemic Filipino women.

Iron deficiency is endemic in much of the world, and food system-based approaches to eradication may be viable with new plant breeding approaches to increase the micronutrient content in staple crops. It is thought that conventional plant breeding approaches provide varieties of rice that have 400-500% higher iron contents than varieties commonly consumed in much of Asia. The efficacy of consuming high-iron rice was tested during a 9-mo feeding trial with a double-blind dietary intervention in 192 religious sisters living in 10 convents around metro Manila, the Philippines. Subjects were randomly assigned to consume either high-iron rice (3.21 mg/kg Fe) or a local variety of control rice (0.57 mg/kg Fe), and daily food consumption was monitored. The high-iron rice contributed 1.79 mg Fe/d to the diet in contrast to 0.37 mg Fe/d from the control rice. The 17% difference in total dietary iron consumption compared with controls (10.16 +/- 1.06 vs. 8.44 +/- 1.82 mg/d) resulted in a modest increase in serum ferritin (P = 0.10) and total body iron (P = 0.06) and no increase in hemoglobin (P = 0.59). However, the response was greater in nonanemic subjects for ferritin (P = 0.02) and body iron (P = 0.05), representing a 20% increase after controlling for baseline values and daily rice consumption. The greatest improvements in iron status were seen in those nonanemic women who had the lowest baseline iron status and in those who consumed the most iron from rice. Consumption of biofortified rice, without any other changes in diet, is efficacious in improving iron stores of women with iron-poor diets in the developing world.

Adult↗
PubMed1991

Restriction fragment length polymorphism in plants and its implications.

In the last decade RFLP analysis has evolved from an idea that seemed promising to a well-established tool that has led to fundamental advances in several fields. Construction of genetic maps has now become feasible in many organisms where it would previously have been impractical. Since genetic maps are of general utility for many sorts of biological research, they cannot fail to have a significant impact in the immediate future. As genetic maps become reconciled with physical maps in several plants, it will become possible to clone virtually any gene. For a plant breeder this will have the effect of broadening the gene pool available for plant improvement to include virtually all organisms, including animals and microorganisms. Much remains to be done, however. We need basic studies of the biochemistry, physiology, and genetics of plants and the insects and pathogens infesting them to be able to identify target genes for cloning. We need basic studies of transformation and gene expression to be able to have introduced genes expressed in transformed plants in the proper amounts and in the desired tissues. It must also be kept in mind that the best of our present technologies only suffice to clone and transform single genes. We will have to make another large jump in capabilities to be able to transfer QTL between plants. Since the most important agronomic traits are controlled by QTL, this effort will have to be undertaken. However, the future looks promising for plant breeding and RFLP analysis. The molecular genetic revolution now has every indication of being transferrable to practical problems such as plant breeding, and the first steps in this transferral have already occurred through the medium of RFLP analysis.

Breeding↗
PubMedDate not supplied

[Seed proteins as markers in resolving the problems of genetic plant resources, selection and seed production].

The article discusses the main directions and prospects of usage of protein and DNA markers in decision applied and theoretical problems of plant genetic resources (gene banks), plant breeding, seed production and seed testing. The examples of usage of protein and DNA markers for solving important problems of applied botany, genetics and plant breeding were considered.

Crops, Agricultural↗
PubMed2006

AOX--a functional marker for efficient cell reprogramming under stress?

Functional markers for stress tolerance can be used in plant breeding to identify genotypes with high yield stabilities under various conditions. Thus, a good marker should show a strong correlation with favourable adaptive plant behaviour. The efficient reprogramming of target cells for yield determination is currently considered to be the most important step towards defining abiotic stress tolerance. In this Opinion article, we propose a role for the alternative oxidase (AOX) gene as a marker for genetic variation in cell reprogramming and yield stability. Evidence to support this idea comes from the metabolic role of alternative respiration under stress, the link between AOX activity and differential growth, and the single nucleotide polymorphism recently observed in AOX genes. We propose an innovative, interdisciplinary and global research strategy for future experimentation on AOX genes that could have an application in plant breeding.

Arabidopsis Proteins↗
PubMed2000

Defined nuclear changes accompany the reprogramming of the microspore to embryogenesis.

The switch of the gametophytic developmental program toward pollen embryogenesis to form a haploid plant represents an important alternative for plant breeding. In the present study, the switch of the gametophytic developmental program toward a sporophytic pathway, "embryogenesis," has been studied in three different plant species, Brassica, tobacco, and pepper. The switch has been induced by stress (heat shock) at the very responsive stage of the microspore, which is the vacuolate period. As a result, the cell nucleus undergoes striking structural changes with regard to late gametophytic development, including alterations of biosynthetic activities and proliferative activity. An enrichment in HSP70 heat-shock protein and in the presence of Ntf6-MAP kinase was observed after inductive treatment in the nuclei during early embryogenesis. This apparently reflected the possible roles of these proteins, specifically the protective role of HSP70 for the nuclear machinery, and signal transduction of Ntf6-MAPK for the entry of cells into proliferation. Importantly, the observed nuclear changes were similar in the three species investigated and represented convenient markers for early monitoring of embryogenesis and selection purposes for obtaining double-haploid plants in plant breeding.

Brassica↗
PubMed1991

Rapid identification of markers linked to a Pseudomonas resistance gene in tomato by using random primers and near-isogenic lines.

An approach to isolating DNA sequences that are linked to important plant genes is described. The strategy is based upon a recent modification of the polymerase chain reaction in which synthetic primers are used to amplify random sequences from genomic DNA. This technique, used in conjunction with near-isogenic lines (which differ only by the presence or absence of the target gene and a small region of surrounding DNA), leads to the rapid identification of sequences linked to the gene of interest. The feasibility of this method has been demonstrated by analyzing a pair of tomato near-isogenic lines that differ for a region on chromosome 5 that contains a gene (Pto) conferring resistance to Pseudomonas syringae pv. tomato. One hundred forty-four random primers were screened on these lines, and seven amplified products were identified that were present in one but not the other line. Of four products that were further investigated, three were confirmed by segregation analysis to be tightly linked to the Pto gene. Linked sequences identified by this method are useful for detecting the presence of the target gene in plant populations (e.g., in plant breeding) and, if very tightly linked, as starting points for a chromosome walk to isolate the gene. Since near-isogenic lines are a typical product of plant breeding and classical genetic studies, this method is applicable to a wide variety of species.

Base Sequence↗