Crop Improvement (crop + improvement)

Distribution by Scientific Domains


Selected Abstracts


Drought Stress and Preharvest Aflatoxin Contamination in Agricultural Commodity: Genetics, Genomics and Proteomics

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 10 2008
Baozhu Guo
Abstract Throughout the world, aflatoxin contamination is considered one of the most serious food safety issues concerning health. Chronic problems with preharvest aflatoxin contamination occur in the southern US, and are particularly troublesome in corn, peanut, cottonseed, and tree nuts. Drought stress is a major factor to contribute to preharvest aflatoxin contamination. Recent studies have demonstrated higher concentration of defense or stress-related proteins in corn kernels of resistant genotypes compared with susceptible genotypes, suggesting that preharvest field condition (drought or not drought) influences gene expression differently in different genotypes resulting in different levels of "end products": PR(pathogenesis-related) proteins in the mature kernels. Because of the complexity of Aspergillus -plant interactions, better understanding of the mechanisms of genetic resistance will be needed using genomics and proteomics for crop improvement. Genetic improvement of crop resistance to drought stress is one component and will provide a good perspective on the efficacy of control strategy. Proteomic comparisons of corn kernel proteins between resistant or susceptible genotypes to Aspergillus flavus infection have identified stress-related proteins along with antifungal proteins as associated with kernel resistance. Gene expression studies in developing corn kernels are in agreement with the proteomic studies that defense-related genes could be upregulated or downregulated by abiotic stresses. [source]


Brachypodium: a new monocot model plant system emerges

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2007
David F Garvin
Abstract The small grass species Brachypodium distachyon (purple false brome) is potentially an ideal model plant system for grass crop research. To realise this potential, a range of genetic and genomic resources have been developed in a very short period of time, and more still are in the pipeline. David Garvin explains how these resources will establish B. distachyon as the newest model plant system and will fill a long-empty void in genomics resources for grass crop improvement. Copyright © 2007 Society of Chemical Industry [source]


Extreme breeding: Leveraging genomics for crop improvement

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2007
Siobhan M Brady
Abstract The genomic revolution has led to dramatic increases in our understanding of plant biology in the past 10 years, especially in model plant species such as Arabidopsis. The technologies associated with this revolution, such as tilling, array mapping, and association mapping, will see widespread application to crop improvement in the near future. The genes for desirable traits identified through such efforts may be introgressed at an accelerated rate into elite germplasm by marker-assisted breeding. Copyright © 2007 Society of Chemical Industry [source]


Kernel texture differences among US soft wheat cultivars,,

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2005
Dr Craig F Morris
Abstract Kernel texture is a key factor in the quality and utilization of soft wheat (Triticum aestivum L), yet the variation in kernel texture among US soft wheat cultivars is largely unknown. This study evaluated the following hypothesis: soft wheat cultivars differ in kernel texture due to minor genetic factor(s). Once identified, selected contrasting cultivars could serve as candidates for crop improvement and future genetic studies. To test the hypothesis, kernel texture (SKCS, Single Kernel Characterization System), NIR (near-infrared reflectance) and Quadrumat break flour yield were evaluated for 30 cultivars drawn from the four major US soft wheat regions and sub-classes (eastern and western soft white winter, soft red winter and Club). Cultivars were grown in replicated trials over 6 site-years in Washington state. The results clearly indicated that relatively large, consistent genetic differences in kernel texture exist among US soft wheat cultivars. SKCS and NIR were fairly well correlated (r = 0.85) and tended to rank cultivars in the same order. However, individual cultivars deviated from this linear relationship and occasionally rankings changed substantially. Trends were observed among the geographical regions and sub-classes, eg the first 13 hardest-ranked positions (SKCS) were held by western cultivars (13 of the 16 total western cultivars). Quadrumat break flour yield provided an independent assessment of kernel texture and was not correlated with SKCS or NIR hardness. Four distinct cultivar groupings were made based on analysis of variance and two-dimensional graphical assessment. Each group represented contrasting levels of kernel texture (SKCS or NIR) and break flour yield. Identification of the specific underlying gene(s) conferring kernel texture variation among US soft wheats awaits the next phase of research. Copyright © 2005 Society of Chemical Industry [source]


Population structure and phylogeography of Solanum pimpinellifolium inferred from a nuclear gene

MOLECULAR ECOLOGY, Issue 7 2004
Ana Lucía Caicedo
Abstract Phylogeographical studies are emerging as a powerful tool for understanding the population structure and evolution of wild relatives of crop species. Because of their value as genetic resources, there is great interest in exploring the distribution of variation in wild relatives of cultivated plants. In this study, we use sequence variation from the nuclear gene, fruit vacuolar invertase (Vac), to investigate the population history of Solanum pimpinellifolium. Solanum pimpinellifolium is a close relative of the cultivated tomato and has repeatedly served as a source of valuable traits for crop improvement. We sequenced the second intron of the Vac gene in 129 individuals, representing 16 populations from the northern half of Peru. Patterns of haplotype sharing among populations indicate that there is isolation by distance. However, there is no congruence between the geographical distribution of haplotypes and their genealogical relationships. Levels of outcrossing decrease towards the southernmost populations, as previously observed in an allozyme study. The geographical pattern of Vac variation supports a centre of origin in northern Peru for S. pimpinellifolium and a gradual colonization along the Pacific coast. This implies that inbreeding populations are derived from outcrossing ones and that variation present at the Vac locus predates the spread of S. pimpinellifolium. The expansion of cities and human agricultural activity in the habitat of S. pimpinellifolium currently pose a threat to the species. [source]


Applying modelling experiences from the past to shape crop systems biology: the need to converge crop physiology and functional genomics

NEW PHYTOLOGIST, Issue 3 2008
Xinyou Yin
Summary Functional genomics has been driven greatly by emerging experimental technologies. Its development as a scientific discipline will be enhanced by systems biology, which generates novel, quantitative hypotheses via modelling. However, in order to better assist crop improvement, the impact of developing functional genomics needs to be assessed at the crop level, given a projected diminishing effect of genetic alteration on phenotypes from the molecule to crop levels. This review illustrates a recently proposed research field, crop systems biology, which is located at the crossroads of crop physiology and functional genomics, and intends to promote communications between the two. Past experiences with modelling whole-crop physiology indicate that the layered structure of biological systems should be taken into account. Moreover, modelling not only plays a role in data synthesis and quantitative prediction, but certainly also in heuristics and system design. These roles of modelling can be applied to crop systems biology to enhance its contribution to our understanding of complex crop phenotypes and subsequently to crop improvement. The success of crop systems biology needs commitments from scientists along the entire knowledge chain of plant biology, from molecule or gene to crop and agro-ecosystem. [source]


Plant genome sequencing: applications for crop improvement

PLANT BIOTECHNOLOGY JOURNAL, Issue 1 2010
David Edwards
Summary DNA sequencing technology is undergoing a revolution with the commercialization of second generation technologies capable of sequencing thousands of millions of nucleotide bases in each run. The data explosion resulting from this technology is likely to continue to increase with the further development of second generation sequencing and the introduction of third generation single-molecule sequencing methods over the coming years. The question is no longer whether we can sequence crop genomes which are often large and complex, but how soon can we sequence them? Even cereal genomes such as wheat and barley which were once considered intractable are coming under the spotlight of the new sequencing technologies and an array of new projects and approaches are being established. The increasing availability of DNA sequence information enables the discovery of genes and molecular markers associated with diverse agronomic traits creating new opportunities for crop improvement. However, the challenge remains to convert this mass of data into knowledge that can be applied in crop breeding programs. [source]


Carbon metabolite sensing and signalling

PLANT BIOTECHNOLOGY JOURNAL, Issue 6 2003
Nigel G. Halford
Abstract The regulation of carbon metabolism in plant cells responds sensitively to the levels of carbon metabolites that are available. The sensing and signalling systems that are involved in this process form a complex web that comprises metabolites, transporters, enzymes, transcription factors and hormones. Exactly which metabolites are sensed is not yet known, but candidates include sucrose, glucose and other hexoses, glucose-6-phosphate, trehalose-6-phosphate, trehalose and adenosine monophosphate. Important components of the signalling pathways include sucrose non-fermenting-1-related protein kinase-1 (SnRK1) and hexokinase; sugar transporters are also implicated. A battery of genes and enzymes involved in carbohydrate metabolism, secondary metabolism, nitrogen assimilation and photosynthesis are under the control of these pathways and fundamental developmental processes such as germination, sprouting, pollen development and senescence are affected by them. Here we review the current knowledge of carbon metabolite sensing and signalling in plants, drawing comparisons with homologous and analogous systems in animals and fungi. We also review the evidence for cross-talk between carbon metabolite and other major signalling systems in plant cells and the prospects for manipulating this fundamentally important aspect of metabolic regulation for crop improvement. [source]


Next generation of elevated [CO2] experiments with crops: a critical investment for feeding the future world

PLANT CELL & ENVIRONMENT, Issue 9 2008
ELIZABETH A. AINSWORTH
ABSTRACT A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO2] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO2] provides a unique opportunity to increase the productivity of C3 crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity. However, only a fraction of available germplasm of crops has been tested for CO2 responsiveness. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment. Selection of promising genotypes and characterization of response mechanisms will only be effective if crop improvement and systems biology approaches are closely linked to production environments, that is, on the farm within major growing regions. Free air CO2 enrichment (FACE) experiments can provide the platform upon which to conduct genetic screening and elucidate the inheritance and mechanisms that underlie genotypic differences in productivity under elevated [CO2]. We propose a new generation of large-scale, low-cost per unit area FACE experiments to identify the most CO2 -responsive genotypes and provide starting lines for future breeding programmes. This is necessary if we are to realize the potential for yield gains in the future. [source]