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At least 217 records · Page 12Linked to original sources
PubMed2003

[Temporal and spatial distribution characteristics of the crop root in intercropping system].

The ecological mechanism of competition and compensation between the crop root systems of two different intercropping patterns, wheat-soybean and corn-cabbage, was studied by field experiment. The results showed that the annual growth peak of wheat-soybean roots in intercropping was interlacing, the growth of root weight and length expressed synchronism, and the peak of root weight was appeared earlier than that of root length. The vertical distribution of the two crops' root system in two intercroppings was reduced gradually along with soil depths, which also showed that the multiple growth waves moved progressively. The root system distributed horizontally in intercropping system also showed a clearly unbalanced distribution. The root system distribution of out-row for corn elongated 20.4-40.8 cm to cabbage rows, but that of cabbage elongated only 8.5-12.6 cm to corn. The cross extent of root systems in corn-cabbage intercropping was decreased from 40.2 cm to 20.1 cm by fertilization, and the place of cross point for root concentrated region was changed from 20.5 cm to 12.4 cm below soil surface by fertilizer supply. The place of cross point for root concentrated region was an important index to decide the degrees of competition.

Brassica↗
PubMed2026

ClearDepthIAS enables automated high-throughput quantification of roots in soil-grown taproot crops.

Understanding root system architecture is critical for improving crop productivity and resilience, yet phenotyping root traits such as root growth angle and rooting depth remains technically challenging, especially at high throughput. Here, we present ClearDepthIAS, a high-throughput imaging and analysis platform that enables nondestructive, automated quantification of root architecture traits in taproot system crops. By capturing and stitching 360° images of roots growing along the transparent walls of pots and applying deep learning-based segmentation (ClearDepth-WRT), we measured wall root shallowness (WRS)-a proxy for root growth angle-with high precision. We demonstrated for the tap root systems of soybean and canola that the system accurately detects root tips, quantifies their vertical distribution, and extracts biologically meaningful traits such as root area, distribution indices, and growth angles. Validation experiments in canola and soybean demonstrated that WRS can correlate with root crown architecture in mature plants, both in greenhouse and field settings. Furthermore, WRS and root distribution indices derived from ClearDepthIAS are predictors of early root architecture and can be correlated with root biomass distribution across soil depths under field conditions; however, environmental interactions may influence these relationships and weaken or even negate such correlations, as observed when comparing field to field variation in root system architecture. Our system enables efficient phenotyping of genetically diverse populations, with medium to high trait heritability, supporting its utility for genome-wide association studies and breeding. ClearDepthIAS accelerates the development of root ideotypes for improved resource acquisition and carbon sequestration, offering a scalable tool for supporting climate-resilient agriculture.

Plant Roots↗
PubMed2005

The International Rice Information System. A platform for meta-analysis of rice crop data.

Ambiguous germplasm identification; difficulty in tracing pedigree information; and lack of integration between genetic resources, characterization, breeding, evaluation, and utilization data are constraints in developing knowledge-intensive crop improvement programs. To address these constraints, the International Crop Information System (www.icis.cgiar.org), a database system for the management and integration of global information on genetic resources and crop improvement for any crop, was developed by genetic resource specialists, crop scientists, and information technicians associated with the Consultative Group for International Agricultural Research and collaborative partners. The International Rice Information System (www.iris.irri.org) is the rice (Oryza species) implementation of the International Crop Information System. New components are now being added to the International Rice Information System to handle the diversity of rice functional genomics data including genomic sequence data, molecular genetic data, expression data, and proteomic information. Users access information in the database through stand-alone programs and Web interfaces, which offer specialized applications and customized views to researchers with different interests.

Breeding↗
PubMed2002

Carbon and nitrogen assimilation in relation to yield: mechanisms are the key to understanding production systems.

Improved understanding of crop production systems in relation to N-supply has come from a knowledge of basic plant biochemistry and physiology. Gene expression leads to protein synthesis and the formation of metabolic systems; the ensuing metabolism determines the capacity for growth, development and yield production. This constitutes the genetic potential. These processes set the requirements for the supply of resources. The interactions between carbon dioxide (CO(2)) and nitrate () assimilation and their dynamics are of key importance for crop production. In particular, an adequate supply of, its assimilation to amino acids (for which photosynthesized carbon compounds are required) and their availability for protein synthesis, are essential for metabolism. An adequate supply of stimulates leaf growth and photosynthesis, the former via cell growth and division, the latter by larger contents of components of the light reactions, and those of CO(2) assimilation and related processes. If the supply of resources exceeds the demand set by the genetic potential then production is maximal, but if it is less then potential is not reached; matching resources to potential is the aim of agriculture. However, the connection between metabolism and yield is poorly quantified. Biochemical characteristics and simulation models must be better used and combined to improve fertilizer-N application, efficiency of N-use, and yields. Increasing N-uptake at inadequate N-supply by increasing rooting volume and density is feasible, increasing affinity is less so. It would increase biomass and N/C ratio. With adequate N, at full genetic potential, more C-assimilation per unit N would increase biomass, but energy would be limiting at full canopy. Increasing C-assimilation per unit N would increase biomass but decrease N/C at both large and small N-supply. Increasing production of all biochemical components would increase biomass and demand for N, and maintain N/C ratio. Changing C- or N-assimilation requires modifications to many processes to effect improvements in the whole system; genetic engineering/molecular biological alterations to single steps in the central metabolism are unlikely to achieve this, because targets are unclear, and also because of the complex interactions between processes and environment. Achievement of the long-term objectives of improving crop N-use and yield with fewer inputs and less pollution, by agronomy, breeding or genetic engineering, requires a better understanding of the whole system, from genes via metabolism to yield.

Agriculture↗
PubMed2006

Ranking the magnitude of crop and farming system effects on soil microbial biomass and genetic structure of bacterial communities.

Biological soil characteristics such as microbial biomass, community structures, activities, and functions may provide important information on environmental and anthropogenic influences on agricultural soils. Diagnostic tools and detailed statistical approaches need to be developed for a reliable evaluation of these parameters, in order to allow classification and quantification of the magnitude of such effects. The DOK long-term agricultural field experiment was initiated in 1978 in Switzerland for the evaluation of organic and conventional farming practices. It includes three representative Swiss farming systems with biodynamic, bio-organic and conventional fertilization and plant protection schemes along with minerally fertilized and unfertilized controls. Effects on microbial soil characteristics induced by the long-term management at two different stages in the crop rotation, i.e. winter wheat after potato or corn, were investigated by analyzing soil bacterial community structures using analysis of PCR-amplified rRNA genes by terminal restriction fragment length polymorphism and ribosomal intergenic spacer analysis. Application of farmyard manure consistently revealed the strongest influence on bacterial community structures and biomass contents. Effects of management and plant protection regimes occurred on an intermediate level, while the two stages in the crop rotation had a marginal influence that was not significant.

Agriculture↗
PubMed2000

A multiple chamber, semicontinuous, crop carbon dioxide exchange system: design, calibration, and data interpretation.

Long-term, whole crop CO2 exchange measurements can be used to study factors affecting crop growth. These factors include daily carbon gain, cumulative carbon gain, and carbon use efficiency, which cannot be determined from short-term measurements. We describe a system that measures semicontinuously crop CO2 exchange in 10 chambers over a period of weeks or months. Exchange of CO2 in every chamber can be measured at 5 min intervals. The system was designed to be placed inside a growth chamber, with additional environmental control provided by the individual gas exchange chambers. The system was calibrated by generating CO2 from NaHCO3 inside the chambers, which indicated that accuracy of the measurements was good (102% and 98% recovery for two separate photosynthesis systems). Since the systems measure net photosynthesis (P-net, positive) and dark respiration(R-dark, negative), the data can be used to estimate gross photosynthesis, daily carbon gain, cumulative carbon gain, and carbon use efficiency. Continuous whole-crop measurements are a valuable tool that complements leaf photosynthesis measurements. Multiple chambers allow for replication and comparison among several environmental or cultural treatments that may affect crop growth. Example data from a 2 week study with petunia (Petunia x hybrida Hort. Vilm.-Andr.) are presented to illustrate some of the capabilities of this system.

Calibration↗
PubMed2006

A low cost decision support tool for the diagnosis of endemic bovine infectious diseases in the mixed crop-livestock production system of sub-Saharan Africa.

Diagnosis and treatment of endemic infectious disease is crucial for productivity of cattle in rural sub-Saharan Africa, but shortages of trained veterinary professionals necessitate support for less well-trained cadres of animal health worker. A Delphi survey of veterinary experts provided quantitative information on key clinical signs associated with eight endemic bovine diseases, then heuristics and dendrogram analysis identified a reduced sign set to be incorporated in a diagnostic decision support tool implemented as a simple colour-banded card. One hundred and seventy disease-sign questionnaire returns were obtained from 32 veterinary research scientists and 14 veterinary practitioners. Preliminary validation of the decision support tool for 16 prototypical cases resulted in 'correct' diagnosis over 90% of the time. The card potentially serves as a training aid and aide-mémoire, and could improve the diagnostic competence of animal healthcare providers.

Africa South of the Sahara↗
PubMed2003

Correlates of children's cognitive skills in an Agrarian community with mixed crop-livestock production systems, Ghinchi, central Ethiopia.

A cross-sectional survey was carried out in Ghinchi farming community, central Ethiopia during October and November 2001 to assess the level of association between children's nutritional status, families' socio-economic gradient, and degree of maternal attention and cognitive development. Ninety children were enrolled in the study, and assessment for cognitive performance was carried out using Bailey Infant Development Scale II. A pilot tested questionnaire was used to collect data on socio-economic status, mothers' care behavior, sanitary conditions of households and feeding pattern, and anthropometry of children. Chronic malnutrition expressed as height for age < -2Z-score of standard was prevalent beginning from the second birthday. Poor cognitive performance was comparatively common in the age group where chronic malnutrition is proportionately prevalent. Logistic regression analysis for variables that demonstrated significant association in correlation study revealed height for age, household possession of consumable durables, maternal care time, type and frequency of feeding and birth order of the child to be significant determinants for cognitive performance of children. Findings implicate a need for comprehensive approach, which incorporates, programs in nutrition, environmental sanitation, family planning, and strategies to reduce maternal workload, to ensure adequate physical and mental development of children.

Agriculture↗
PubMed2003

Engineering central metabolism in crop species: learning the system.

Over many centuries much effort has been expended on crop improvement, most recently by use of molecular genetic technologies. Although genome sequence information for crop species is not yet available in the public domain, most of the genes of central metabolism have already been cloned and the corresponding transgenic plants generated. Although these plants have often confirmed the hypotheses based on more indirect methodologies, they have also produced unexpected challenges to the metabolic engineer in outlining the enormous flexibility and complexity inherent in plant metabolism. Intriguingly, comparison of transcript and metabolite levels of the TCA cycle revealed strong correlations in expression levels but little coordination in the levels of metabolic intermediates. These factors explain why many attempts to engineer central metabolism have proven unsuccessful to date and suggest that a greater understanding of the regulatory circuits and networks controlling metabolism is required before engineering can become routine. In this article we intend to illustrate these challenges by reviewing attempts to manipulate the central metabolic pathways of Solanaceae (sps.) as well as demonstrating the role for systems biology approaches in metabolic engineering in crops.

Agriculture↗
PubMed2005

Quantification of imidacloprid uptake in maize crops.

The systemic imidacloprid is one of the most used insecticides in the world for field and horticultural crops. This neurotoxicant is often used as seed-dressing, especially for maize, sunflower, and rape. Using a LC/MS/MS technique (LOQ = 1 microg/kg and LOD = 0.1 microg/kg), the presence of imidacloprid has been measured in maize from field samples at the time of pollen shed, from less than 0.1 microg/kg up to 33.6 microg/kg. Numerous random samples were collected throughout France from 2000 to 2003. The average levels of imidacloprid measured are 4.1 microg/kg in stems and leaves, 6.6 microg/kg in male flowers (panicles), and 2.1 microg/kg in pollen. These values are similar to those found previously in sunflower and rape. These results permit evaluation of the risk to honeybees by using the PEC/PNEC ratios (probable exposition concentrations/predicted no effect concentration). PEC/PNEC risk ratios were determined and ranged between 500 and 600 for honeybees foraging on maize treated with imidacloprid by seed dressing. Such a high risk factor can be related to one of the main causes of honeybee colony losses.

Flowers↗
PubMed2002

Ethanol vapor is an efficient inducer of the alc gene expression system in model and crop plant species.

We have demonstrated that low concentrations of ethanol vapor efficiently induce the alc gene expression system in tobacco (Nicotiana tabacum cv Samsun NN), potato (Solanum tuberosum cv Solara), and oilseed rape (Brassica napus cv Westar). For many situations, this may be the preferred method of induction because it avoids direct application of comparatively high concentrations of an ethanol solution. Although induction was seen with less than 0.4 microM ethanol vapor, maximal induction of the chloramphenicol acetyl transferase gene was achieved after 48 h in leaves of tobacco plants enclosed with 4.5 microM ethanol vapor. In the absence of ethanol, there is no detectable gene expression. Treatment of potato tubers with ethanol vapor results in uniform beta-glucoronidase (GUS) expression. Vapor treatment of a single oilseed rape leaf resulted in induction of GUS in the treated leaf only and (14)C-ethanol labeling in tobacco confirmed that the inducer was not translocated. In contrast, enclosure of the roots, aerial parts, or whole plant with ethanol vapor resulted in induction of GUS activity in leaves and roots. The data reported here broaden the utility of the alc system for research and crop biotechnology.

Brassica napus↗
PubMed2003

Carbon balance in bioregenerative life support systems: some effects of system closure, waste management, and crop harvest index.

In Advanced Life Support (ALS) systems with bioregenerative components, plant photosynthesis would be used to produce O2 and food, while removing CO2. Much of the plant biomass would be inedible and hence must be considered in waste management. This waste could be oxidized (e.g., incinerated or aerobically digested) to resupply CO2 to the plants, but this would not be needed unless the system were highly closed with regard to food. For example, in a partially closed system where some of the food is grown and some is imported, CO2 from oxidized waste when combined with crew and microbial respiration could exceed the CO2 removal capability of the plants. Moreover, it would consume some O2 produced from photosynthesis that could have been used by the crew. For partially closed systems it would be more appropriate to store or find other uses for the inedible biomass and excess carbon, such as generating soils or growing woody plants (e.g., dwarf fruit trees). Regardless of system closure, high harvest crops (i.e., crops with a high edible to total biomass ratio) would increase food production per unit area and O2 yields for systems where waste biomass is oxidized to recycle CO2. Such interlinking effects between the plants and waste treatment strategies point out the importance of oxidizing only that amount of waste needed to optimize system performance.

Biomass↗
PubMed1997

Incineration of biomass and utilization of product gas as a CO2 source for crop production in closed systems: gas quality and phytotoxicity.

This study addressed the recycle of carbon from inedible biomass to CO2 for utilization in crop production. Earlier work identified incineration as an attractive approach to resource recovery from solid wastes because the products are well segregated. Given the effective separation of carbon into the gaseous product stream from the incinerator in the form of CO2 we captured the gaseous stream produced during incineration of wheat inedible biomass and utilized it as the CO2 source for crop production. Injection rate was based on maintenance of CO2 concentration in the growing environment. The crop grown in the closed system was lettuce. Carbon was primarily in the form of CO2 in the incinerator product gas with less than 8% of carbon compounds appearing as CO. Nitrogen oxides and organic compounds such as toluene, xylene, and benzene were present in the product gas at lower concentrations (< 4 micromol mol-1); sulfur containing compounds were below the detection limits. Direct utilization of the gaseous product of the incinerator as the CO2 source was toxic to lettuce grown in a closed chamber. Net photosynthetic rates of the crop was suppressed more than 50% and visual injury symptoms were visible within 3 days of the introduction of the incinerator gas. Even the removal of the incinerator gas alter two days of crop exposure and replacement with pure CO2 did not eliminate the toxic effects. Both organic and inorganic components of the incinerator gas are candidates for the toxin.

Air Pollutants↗
PubMed2001

An optimal control strategy for crop growth in advanced life support systems.

A feedback control method for regulating crop growth in advanced life support systems is presented. Two models for crop growth are considered, one developed by the agricultural industry and used by the Ames Research Center, and a mechanistic model, termed the Energy Cascade model. Proportional and pointwise-optimal control laws are applied to both models using wheat as the crop and light intensity as the control input. The control is particularly sensitive to errors in measurement of crop dry mass. However, it is shown that the proposed approach is a potentially viable way of controlling crop growth as it compensates for model errors and problems associated with applying the desired control input due to environmental disturbances. Grant numbers: NGT5-50229.

Biomass↗
PubMedDate not supplied

Transgenic foods as a tool for malnutrition elimination and their impact on agricultural systems.

GMO crops were introduced for commercial production in 1996. Since then, their use has increased rapidly. GMOs have primarily benefited large farms and multinational companies in Industrialised Countries and now is more and more debating their utilisation in Developing World. The objective of the present review is an analysis of this subject from a comprehensive point of view; in addition to that, the changes related to the nutritional content of transgenic foods will be treated. Despite the progress that has been made, the world food situation is still marked by mass hunger and chronic malnutrition. In particular micronutrient malnutrition, that means vitamin and mineral deficiencies, represents an important public health problem in several areas of the world. The "golden rice" bioengineered to contain beta-carotene, as a source of vitamin A is the most famous example of GM food used for reduction (or even to solve) of a public health problem. The expected results of this approach have presently not been achieved. Further studies are necessary to increase the general knowledge about GMOs and their long-term effects on human health. Collaborative attitude of different research sectors (private and public) and involvement of different sectors of society will be an added value for comprehension of the real impact of the application of modern biotechnology to food and agriculture systems.

Agriculture↗
PubMed2000

Increasing expression of P450 and P450-reductase proteins from monocots in heterologous systems.

Monocotyledonous crop plants are usually more resistant to herbicides than grass weeds and most dicots. Their resistance to herbicides is mediated in many cases by P450 oxygenases. Monocots thus constitute an appealing source of P450 enzymes for manipulating herbicide resistance and recombinant forms of the major xenobiotic metabolizing mooxygenases are potential tools for the optimization of new active molecules. We report here the isolation and functional characterization of the first P450 and P450 reductase coding sequences from wheat. The first attempts at expressing these cDNAs in yeast and tobacco led to levels of protein, which were extremely low, often not even detectable. The wheat P450 cDNAs were efficiently transcribed, but no protein or activity was found. Wheat coding sequences, like those of other monocots, are characterized by a high GC content and by a related strong bias of codon usage, different from that observed in yeast or dicots. Complete recoding of genes being costly, the reengineering their 5'-end using a single PCR megaprimer designed to comply with codon usage of the host was attempted. It was sufficient to relieve translation inhibition and to obtain good levels of protein expression. The same strategy also resulted in a dramatic increase in protein expression in tobacco. A basis for the success of such a partial recoding strategy, much easier and cheaper than complete recoding of the cDNA, is proposed.

Amino Acid Sequence↗