Glyphosate-resistant crops: history, status and future

The commercial launch of glyphosate-resistant soybeans in 1996 signaled the beginning of a new era in weed management in row crops. Today, over 80% of the soybeans grown in the USA are glyphosate resistant. Since that time, many crops have been transformed that have allowed crop applications of many classes of herbicide chemistries. Crops currently under production include maize, soybean, cotton and canola. Transformation technology and selection methods have improved and the rate of development as well as the breadth of crops being considered as commercial targets has increased. On the basis of recent adoption rates by growers around the world, it appears that glyphosate-resistant crops will continue to grow in number and in hectares planted. However, global public acceptance of biotechnology-derived products will continue to impact the rate of adoption of this and other new innovations derived from transformation technology.     

Influence of herbicide-resistant canola on the environmental impact of weed management

The growth of herbicide-resistant canola varieties increased from 10% of the canola area in Canada in 1996, when the technology was first introduced, to 80% in 2000. From 1995 to 2000, the amount of herbicide active ingredient applied per hectare of canola declined by 42.8% and the Environmental Impact (EI) per hectare, calculated using the Environmental Impact Quotient for individual herbicides and the amounts of active ingredients applied, declined 36.8%. The amount of herbicide active ingredient per hectare applied to conventional canola was consistently higher than that applied to herbicide-resistant canola each year between 1996 and 2000. Similarly, the EI of herbicide use per hectare in conventional canola was higher than that of herbicide-resistant canola during the same time period. Since 1996, herbicide use has shifted from broadcast applications of soil-active herbicides to post-emergence applications of herbicides with broad-spectrum foliar activity. The decline in herbicide use and EI since the introduction of herbicide-resistant varieties was due to increased use of chemicals with lower application rates, a reduced number of applications and a decreased need for herbicide combinations.     

The toxicities of some analogues of dieldrin,endosulfan and isobenzan to bloodsucking diptera,especially tsetse flies

The dieldrin analogue, 1, 8, 9, 10, 11, 11-hexachloro-4, 5-exo-epoxy-2, 3-7, 6-endo-tricyclo-[6.2.1.0^{2, 7}]undec-9-ene (HEOM), and the isomeric 3, 4-exo-epoxy-and 3, 6-endo-epoxy compounds (HCE and ODA, respectively), incorporating structural modifications of the non-chlorinated ring system, were tested against adult mosquitoes (mainly Anopheles stephensi List.), tsetse flies (mainly Glossina austeni Newst.) and stable flies, Stomoxys calcitrans (L.). The order of toxicity was ODA > HCE > HEOM. In further tests of residual activity against A. stephensi, ODA was better than HCE but neither was sufficiently persistent to be a promising mosquito toxicant. Analogues of dieldrin (HEOD), endosulfan and isobenzan with reduced numbers of chlorine atoms were tested against G. austeni. In the pentachloro-analogues of dieldrin and α-endosulfan, the anti-bridge chlorine was more important than the syn-chlorine for toxicity. The general effect of reductive dechlorination was to reduce toxicity, but the effect was small for some endosulfan analogues and in one case there was an increase in toxicity. In the main, toxicities of the endosulfan analogues compared favourably with those of the dieldrin analogues. However, toxicity fell drastically following replacement of the second ethylenic chlorine in isobenzan. The effect of these structural changes on toxicity evidently varied from one series to another and was influenced in an unpredictable manner by the rest of the molecule.     

Solar input and energy storage in a five-year-old American sycamore plantation

Energy stored in a 5-year-old American sycamore plantation grown in Mississippi was determined by bomb calorimetry of component parts of selected trees randomly sampled in autumn and spring. The results indicated significant differences among tree components. The caloric values were 4675.81 cal g^?1 for leaves, 4631.76 cal g^?1 for branch bark, 4489.12 cal g^?1 for branch wood, 4753.85 cal g^?1 for stem bark, and 4488.76 cal g^?1 for stem wood. Based on these caloric values, the total energy yeild for a 1-ha plantation, containing 1200 trees with a total above-ground biomass of 20.3 t, was computed at 9.22 × 10¹⁰ calories. The storage efficiency of the forest stand, which was calculated by dividing total energy yields by available photosynthetic solar radiation received during the growing season (168,462 × 10⁸ cal), was 0.55%. The biomass yield of this 5-year-old sycamore plantation is sufficient to supply the electrical energy needs of an average household for nearly 3 years.     

EMPHYSEMATOUS CHOLECYSTITIS IN THE NONDIABETIC DOG: THREE CASE HISTORIES

Emphysematous cholecystitis not associated with diabetes mellitus was diagnosed in three dogs. All three dogs were examined because of vomiting. Neutrophilia, elevated serum alkaline phosphatase, and normal serum glucose were present in each animal. A gas-filled gallbladder and pericholecystic gas were seen radiographically in all three dogs; a cholecystolith was present in one dog. A cholecystectomy was performed on two dogs. Cultures of bacteria from these two bladders revealed Clostridium sp. One of these dogs was euthanized because of acute renal tubular necrosis that was diagnosed after ten days of treatment with gentamicin. The second dog recovered without incident. The third dog was treated successfully with antibiotics.     

Soybean shoot metabolism of isopropyl-3-chlorocarbanilate: Ortho and para aryl hydroxylation

This laboratory reported that isopropyl-3-chlorocarbanilate-phenyl-U-¹⁴C (chlorpropham-phenyl-¹⁴C) was absorbed, translocated, and metabolized by soybean plants. Both polar metabolites and insoluble residues were found in roots, whereas only polar metabolites were found in shoot tissues. In both roots and shoots the polar metabolites were shown to be the O-glucoside of isopropyl-2-hydroxy-5-chlorocarbanilate (2-hydroxy-chlorpropham). In shoot tissue there were other polar metabolites that were not identified. The experiments with soybeans have been repeated, but with new isolation and purification procedures. The plants were root treated with both chlorpropham-phenyl-¹⁴C and isopropyl-3-chlorocarbanilate-2-isopropyl-¹⁴C. The roots and shoots were extracted and separated into the polar, nonpolar, and insoluble metabolic components, using the Bligh-Dyer extraction method. The polar metabolites were separated by gel permeation chromatography. Further purification was accomplished on Amberlite XAD-2. The polar metabolites from the shoot and root tissues were hydrolyzed either by β-glucosidase or hesperidinase. The enzyme liberated aglycones were derivatized and separated by gas-liquid chromatography, and the components were characterized by mass spectrometry or NMR. The results of this study showed that the polar metabolites of soybean shoots were 2-hydroxy-chlorpropham and isopropyl-4-hydroxy-3-chlorocarbanilate (4-hydroxy-chlorpropham). These two hydroxy-chlorpropham metabolites were found in soybean shoots at a ratio of approximately 1:1. The only aglycone found in root tissue was 2-hydroxy-chlorpropham. Using the new procedures, no evidence was obtained for the presence of the unidentified polar metabolites that were previously observed in shoot tissues.     

Mapping Grain Sorghum Yield Variability Using Airborne Digital Videography

Mapping crop yield variability is one important aspect of precision agriculture. Combine-mounted yield monitors are becoming widely available for measuring and mapping yields for different crops. This study was designed to assess airborne digital videography as a tool for mapping grain sorghum yields for precision farming. Color-infrared (CIR) imagery was acquired with a three-camera digital video imaging system from two grain sorghum fields in south Texas over the 1995 and 1996 growing seasons. The multispectral video data obtained during the bloom to soft dough stages of plant development were related to hand-harvested grain yields at sampling sites determined from unsupervised image classification maps of the two fields. Significant correlations were found between grain yields and the red band, the green band, and the normalized difference vegetation index (NDVI). Regression equations were developed to describe the relations between grain yields and each of the three significant spectral variables using an exponential model and two segmented models. Multiple linear regression equations were also determined to relate grain yields to the three bands and NDVI. These equations were then used to estimate grain yields at each video image pixel within each field and to generate grain yield maps. Comparisons of the estimated average yields from the regression equations with the actual yields indicated that yield estimation errors from the equations ranged from 0.0 to 10.0% in 1995 and from 0.2 to 7.3% in 1996 for field 1, and from 4.0 to 11.2% in 1995 and 6.3 to 12.5% in 1996 for field 2. Although the equations developed for one field in a given year may not apply to the same field in any other year, the practical value of these relationships is for mapping within-field grain yield variations. The results from this study showed that airborne digital videography, combined with ground sampling, regression analysis, and image processing, could be a useful approach for mapping spatial crop yield variability within fields.     

Suharto's Fall and Afterwards: Medititations Provoked by Four Recent Analyses

Books reviewed in this article: Edward Aspinall, et al, (eds) The last days of President Suharto Richard W. Baker, et al, (eds) Indonesia: The Challenge of Change Arief Budiman, et al, (eds) Reformasi: Crisis and change in Indonesia Geoff Forester, (ed) Post‐Soeharto Indonesia: Renewal or Chaos?     

A review: The beneficial effects and possible mechanisms of aluminum on plant growth in acidic soil

Aluminum(Al) is the third most abundant element in the earth's crust and a major factor inhibiting plant growth and reducing crop yield in acidic soil. Although there is substantial research on the phytotoxic effects and the underlying mechanisms of Al by applying Al alone hydroponically, soil is a complex medium containing numerous mineral elements that can interact with Al and other elements and their bioavailability in plants. In this review, we describe the roles of Al in promoting plant growth, enhancing phosphorus availability and efficient use in plants, and alleviating H+, iron, and manganese toxicity in acidic conditions. Furthermore, we discuss the possible mechanisms of enhanced abiotic stress tolerance induced by Al. We also elucidate the role of Al in attracting plant growth promoting rhizo-bacteria(PGPR) and their interactions with plants by increasing organic exudates.     

Strategies for empowering the local people to participate in forest restoration

Within various parts of the tropics and temperate regions, there are increasingly more efforts towards reforestation or restoration. Interventions in the tropics however, have not adequately addressed the needs of local people compelling them to degrade forests. We conducted a study in and around Mabira Forest Reserve in Uganda with the aim of assessing locally proposed restoration techniques and conditions for empowering local people to raise their willingness to participate in forest restoration practices. We specifically set out to; (i) identify proposed techniques to restore the degraded forests, and (ii) determine the pre-conditions for supporting local people’s participation in restoration activities. Data were collected using individual semi-structured interviews, focus group discussions and participatory forest surveys. The findings show that the local people mainly engaged in practices that address their needs concurrently. The most reported practices include: planting trees on farm, enrichment tree planting in the forest, control of soil erosion, and control of invasive alien species. The main pre-conditions for their participation in forest restoration is assurance for more access to forest resources. The efficiency of local people in restoration will be enhanced by strengthening their capacity for collaborative forest management, raising their awareness on restoration, building their capacity, as well as continuous monitoring by forest managers.