The chemical weed control of maize culture in the Danube meadow

In the world, maize covers about 150 million hectares, following close to rice and wheat. (Balteanu 2000) In Romania, maize culture covers an area of more than 3,500,000 hectares from the overall arable soil, being cultivated in all Romanian districts. Chemical weed control took the greatest extension in the world, at the same time with the synthesis of Atrazine, in 1956, in the laboratories of J.R. Geigy Company, as a super-selective herbicide for the maize culture. This is why many researchers from all continents studied weed control of maize culture, using Atrazine together with other 50 herbicides synthesized until 2004. In the embanked meadow of the Danube, from the 500,000 hectares of arable soil, the maize covers the greatest area. For this reasons, the chemical weed control was granted a great attention by using different herbicides based on Atrazine, Alachlor, Acetochlor, Butilat, Pendimethalin, Dicamba, 2,4-D. At the same time, in the experiments from the Danube Meadow, the authors also studied the efficiency of some combined herbicides: Butizin, Magnific, Guardian Extra is Tazastomp.     

Weed control in sunflower (helianthus annuus L.) with post-emergent herbicides

Sunflower is the most important oil crop in Hungary, is the base of the production of cooking oil and moreover takes an important part in production of margarine too. Extracted sunflower groats as a secondary product origining from the mentioned procedure can be used in forage successfully. The amount of harvested sunflower reaches the 20-25% of the EU's yield. The sowing area approaches 500 thousand hectares. The essential condition of successful crop production is the perfect weed control. Sowing areas are infected with monocotyledon and dicotyledonous weeds too. Annual dicotyledonous weeds are the most troublesome. The worst species is the Ambrosia artemisiifolia L. Many other weed species as Abutilon theophrasti MEDIC., Datura stramonium L. and Xanthium strumarium L. can cause serious damages. In our model experiments we examined the herbicide sensibility of two commercial sunflower cultivars as "Iregi szürke csikos", "Marica II" and a sulfonylurea-urea tolerant new hybrid "PR63E82". The experiment was set up under greenhouse conditions with the use of four important weed and different post-emergent herbicide as Modown 4F (bifenox), Pledge 50 WP (flumioxazin) and Granstar 75 DF (tribenuron-methyl). We applied normal and double doses too. Sunflower was cultivated to 4-6 leaf stage. Post-emergent herbicides were sprayed out when weeds were in 2, 2-4 and 4-6 leaf stage. Weed killer and phytotoxic effects of post-emergent herbicides were examined. We declared that development of weeds had significally effect on the effectiveness of different herbicides.     

The chemical control of Shorgum halepense (Johnson grass) in soybean culture in the Danube meadow

Soybean cultures, especially those from the Danube Meadow, are very strongly infested with Johnson grass, which causes big damages, by the reduction of production with 40-85%, depending on the infestation degree. Before the synthesis of special herbicides for Johnson grass control, this species was controlled by practicing deep tilling, repeated operations with the disk, and, after the sprouting of soy plants, by mechanical and manual hoeings. In the Danube Waterside, the lack of labour force for the manual hoeing is very sharp. For this reason, it was generalized the enlarged use of herbicides for annual weed control (monocotyledonous and dicotyledonous), including Johnson grass. For the control of Johnson grass species, in the conditions of the Danube Meadow, the best results were obtained with the herbicides Fusilade Super, Targa Super, Agil and Select, and for the control of annual dicotyledonous species, with the herbicide Pivot 100LC.     

No-tillage system applied to the sunflower (hybrid pioneer PR64E83) resistant to the tribenuron-methyl in the conditions from Romania

In the year 2006, the first experience with the NO-TILLAGE system for sunflower crops was organized in Romania, using the Pioneer PR64E83 sunflower hybrid resistant to the tribenuron-methyl herbicide. The experience took place in the Danube river flood plain, on an alluvial soil with a content between 3.1-4.5% and a content of clay of 34-40%. In the conventional system, in the fall of the year 2005, autumn ploughing was carried out, along with harrowing, and in spring the land was tilled two more times, using both the disk and the harrow. Before sowing, the land was prepared by using the combiner-machine. After the sunflower sprouted, three-time mechanical hoeing between the rows, as well as three-time manual hoeing on the sunflower row were performed. In the no-tillage system, no autumn ploughing, nor any other soil work were performed, and the sunflower was sowed directly, by using the Gaspardo seeder. Before sowing, the soil was covered in proportion of 70% by species of weeds of the Cirsum, Sonchus and Polygonum amphibium type. To destroy these species of weeds, 3 days before sowing, the soil was treated with the Roundup herbicide in a dose of 7 litres/ha. After the sunflower sprouted, when the plants had 4-5 leaves, the following sulphonylurea herbicides were applied post-emergently. (1) Express 50SG--which contains tribenuron-methyl (2) Granstar 75DF--which contains 75% tribenuron-methyl (3) Titus 25DF--which contains 25% rimsulfuron (4) Mistral--which contains 40 g/L nicosulfuron (5) Lintur 70WG--which contains 4.1% triasulfuron + 65.9% dicamba (6) Peak 75WG--which contains 75% prosulfuron The Express 50SG and Granstar 75DF herbicides were selective for the sunflower hybrid PR64E83, and the other herbicides although belonging o the same sulphonylurea group, they proved to have a very phytotoxic effect upon the sunflower crop. In the report, selectivity is presented depending on the dose of herbicide, weed control and sunflower production.     

Weed control using allelopathic sunflowers and herbicide

Summary Field studies were conducted to determine if season long weed control could be achieved by combining the use of an herbicide with the natural allelochemicals produced by cultivated sunflower (Helianthus annuus L.). The weed biomass was reduced equally in plots planted with sunflowers, whether or not the herbicide was applied in each of 4 years. Weed control diminished the second year in all plots that received the same treatments as had been applied the previous year. This diminished efficacy was attributed to reduced emergence of sunflower (13.5 to 45.2 percent) in second-year plots, as a result of autotoxicity from sunflower crop residues remaining after the first-year harvest.     

Overview of the current status of genetically modified plants in Europe as compared to the USA

Genetically modified crops have been tested in 1,726 experimental releases in the EU member states and in 7,815 experimental releases in the USA. The global commercial cultivation area of genetically modified crops is likely to reach 50 million hectares in 2001, however, the commercial production of genetically modified crops in the EU amounts to only a few thousand hectares and accounts for only some 0.03% of the world production. A significant gap exists between the more than fifty genetically modified crop species already permitted to be cultivated and to be placed on the market in the USA, Canada and other countries and the five genetically modified crop species permitted for the same use in the EU member states, which are still pending inclusion in the Common Catalogue of agricultural plant species. The further development of the "green gene technology" in the EU will be a matter of public acceptance and administrative legislation.     

The economic dimension of directing treated wastewater to the production of green fodder in Saudi Arabia

This study aimed to identify the economic dimension of directing treated wastewater to the production of green fodder. To achieve its objectives, the study relied on economic equations, the method of using multiple criteria, and a scoring technique for prioritization. The study showed that green fodder is a crop that depletes water, as it consumes about 67.27% of the water used for agricultural purposes. In determining the priority of regions intending to use treated wastewater, the ranking put Riyadh region first, followed by the eastern region, the Qassim region, Hail, Makkah Al-Mukarramah, Tabuk, Asir, Al-Jawf, Jizan, Madinah, Najran, the northern borders, and Al-Baha, in this order. The area that can be cultivated with forage crops is estimated to be about 53.05 thousand hectares, with a production of 953.75 thousand tons. The cost of treating wastewater to make it usable amounts to 2126.22 million riyals, while the value of the benefits gained from its use is 2508.95 million riyals; thus, the Saudi agricultural economy achieves a net gain estimated at about 382.73 million riyals annually. Therefore, this study recommends the use of treated wastewater in the production of green fodder.     

The biology and host specificity of the stem-boring weevilListronotus setosipennis [Col.: Curculionidae] A potential biocontrol agent forParthenium hysterophorus [Asteraceae]

The stem-boring weevilListronotus setosipennis (Hustache) is widespread and damaging to its hostParthenium hysterophorus L. in northern Argentina and southern Brazil. In detailed host-testing it was shown to have a restricted host-range and, despite some feeding and development on sunflower in tests, to be a safe biological control agent againstP. hysterophorus. Field releases in Queensland, Australia took place from 1982 to 1986 and the weevil has established over several thousand hectares at numerous sites. Spread is however slow and the effect on the plant still negligible.      

An evaluation of the role of ethylene in herbicidal injury induced by picloram or clopyralid in rapeseed and sunflower plants

The role of ethylene in herbicidal injury induced by 4-amino-3,5,6-trichloropicolinic acid (picloram) or 3,6-dichloropicolinic acid (clopyralid) was investigated in sunflower (Helianthus annuus L.) and rapeseed (Brassica napus L. cv Altex). Picloram induces herbicide injury in both species, whereas clopyralid induces injury only in sunflower. Picloram applied to the third leaf of a rapeseed plant increased ethylene evolution several-fold. Clopyralid had no effect on ethylene production in rapeseed. In sunflower, both picloram and clopyralid elevated ethylene production. Ethylene biosynthesis induced by the herbicide treatment was not restricted to treated areas. When clopyralid was applied only to the lower stem and cotyledons of sunflower, the herbicide treatment resulted in an increase in the rate of ethylene production from the true leaves. Increased ethylene production preceded or coincided with the onset of morphological responses induced by a herbicide application to a susceptible species. The contrast in ethylene production by these two plant species cannot be accounted for by differences in absorption and translocation of clopyralid and picloram.

Treatment with aminoethoxyvinylglycine (AVG) before picloram or clopyralid application prevented an increase in ethylene production. Pretreatment with AVG also delayed the development of morphological changes induced by picloram or clopyralid. It appears that enhanced ethylene biosynthesis after application of picloram or clopyralid to the susceptible plant species was a factor involved in resulting morphological changes.

     

Callus formation from isolated sunflower (Helianthus annuus) mesophyll protoplasts

Mesophyll protoplasts of the cultivated sunflower,Helianthus annuus, have been consistently found not to divide or regenerate calli, despite the efforts of several groups. In the present report, we describe the conditions for donor plant culture, protoplast isolation, and their culture that were suitable for repeated regeneration of green, nodular, vigorously growing calli from isolated sunflower mesophyll protoplasts. The best conditions for protoplast isolation employed the use of both CAYLA cellulase and CAYLA pectinase. Culture conditions were not much different from those established earlier for sunflower hypocotyl protoplasts. The most startling observation was the great variability of division frequencies between experiments even under strictly controlled, identical experimental conditions. This finding points to an important influence of a variable in the physiological state of the donor plant which is difficult to control.     

Assessment of the bacterial community structure in a Brazilian clay soil treated with atrazine

In the present paper, the bacterial communities in two soils, one from an agricultural sugarcane cropped field and the other from an unperturbed soil with similar geopedological characteristics, were characterized using the Fluorescence In Situ Hybridization (FISH) method. FISH consists of in situ identification of bacteria using fluorescent labeled 16S rRNA targeted oligonucleotide probes visualizable under epifluorescence microscope. In the cultivated soil, in line with agricultural practice, the pre-emergence herbicide atrazine had been regularly applied each year at a concentration of 5 L/ha. The Shannon Diversity and Evenness Indices were also calculated using the phylogenetic data obtained from the FISH analysis. Although, at the sampling time (6 months after soil atrazine treatment), no residual herbicide concentration was found, the overall bacterial community results show a lower diversity and evenness in the agricultural soil than in the unperturbed one, demonstrating how microbiological indicators are sensitive to anthropogenic disturbance. In the natural soil, the dominant groups were α-Proteobacteria, β-Proteobacteria, and γ-Proteobacteria (representing more than 50 % of the bacteria), but in the agricultural soil, their abundance decreased significantly and represented just 31 % of the bacteria domain.     

Adaptation to high temperature mitigates the impact of water deficit during combined heat and drought stress in C3 sunflower and C4 maize varieties with contrasting drought tolerance

Heat and drought stress frequently occur together, however, their impact on plant growth and photosynthesis (P_N) is unclear. The frequency, duration and severity of heat and drought stress events are predicted to increase in the future, having severe implications for agricultural productivity and food security. To assess the impact on plant gas exchange, physiology and morphology we grew drought tolerant and sensitive varieties of C3 sunflower (Helianthus annuus) and C4 maize (Zea mays) under conditions of elevated temperature for 4 weeks prior to the imposition of water deficit. The negative impact of temperature on P_N was most apparent in sunflower. The drought tolerant sunflower retained ribulose‐1,5‐bisphosphate carboxylase/oxygenase (RubisCO) activity under heat stress to a greater extent than its drought sensitive counterpart. Maize exhibited no varietal difference in response to increased temperature. In contrast to previous studies, where a sudden rise in temperature induced an increase in stomatal conductance (G_s), we observed no change or a reduction in G_s with elevated temperature, which alongside lower leaf area mitigated the impact of drought at the higher temperature. The drought tolerant sunflower and maize varieties exhibited greater investment in root‐systems, allowing greater uptake of the available soil water. Elevated temperatures associated with heat‐waves will have profound negative impacts on crop growth in both sunflower and maize, but the deleterious effect on P_N was less apparent in the drought tolerant sunflower and both maize varieties. As C4 plants generally exhibit water use efficiency (WUE) and resistance to heat stress, selection on the basis of tolerance to heat and drought stress would be more beneficial to the yields of C3 crops cultivated in drought prone semi‐arid regions.     

Genetic diversity and population structure in cultivated sunflower and a comparison to its wild progenitor, <Emphasis Type="Italic">Helianthus annuus</Emphasis> L

Crop germplasm collections are valuable resources for ongoing plant breeding efforts. To fully utilize such collections, however, researchers need detailed information about the amount and distribution of genetic diversity present within collections. Here, we report the results of a population genetic analysis of the primary gene pool of sunflower (Helianthus annuus L.) based on a broad sampling of 433 cultivated accessions from North America and Europe, as well as a range-wide collection of 24 wild sunflower populations. Gene diversity across the cultivars was 0.47, as compared with 0.70 in the wilds, indicating that cultivated sunflower harbors roughly two-thirds of the total genetic diversity present in wild sunflower. Population structure analyses revealed that wild sunflower can be subdivided into four genetically distinct population clusters throughout its North American range, whereas the cultivated sunflower gene pool could be split into two main clusters separating restorer lines from the balance of the gene pool. Use of a maximum likelihood method to estimate the contribution of the wild gene pool to the cultivated sunflower germplasm revealed that the bulk of the cultivar diversity is derived from two wild sunflower population genetic clusters that are primarily composed of individuals from the east-central United States, the same general region in which sunflower domestication is believed to have occurred. We also identified a nested subset of accessions that capture as much of the allelic diversity present within the sampled cultivated sunflower germplasm collection as possible. At the high end, a core set of 288 captured nearly 90% of the alleles present in the full set of 433, whereas a core set of just 12 accessions was sufficient to capture nearly 50% of the total allelic diversity present within this sample of cultivated sunflower.     

向日葵分子生物学研究进展

向日葵是一种营养价值极高的资源植物,向日葵的研究和生产在当前我国中西部大开发的战略中具有重要的意义。本文对近年来国内外向日葵分子生物学研究的最新进展,在蛋白质、酶、基因及基因工程、分子标记等方面进行了综述。特别对生化标记、分子标记技术在向日葵研究上的应用及所取得的成果作了重点介绍,并对今后向日葵研究工作进行了展望。     

Translocation and Complex Formation of Picloram and 2,4-D in Rape and Sunflower

Uptake, translocation and complex formation of ¹⁴C-labelled 4-amino-3,5,6-trichloropicolinic acid (picloram) and 2,4-dichlorophenoxyacetic acid (2,4-D) in seedlings of rape (Brassica napus L. cv. Nilla) and sunflower (Helianthus annuus L. var. uniflorus) were studied. Sunflower is susceptible both to 2,4-D and picloram, while rape is susceptible to 2,4-D but more tolerant to picloram. The uptake of the herbicides through the leaves was almost complete in both species. Translocation of 2,4-D into the roots took place more readily than that of picloram. In sunflower about 50 per cent of the applied 2,4-D was extruded through the roots into the nutrient solution after 9 days. In the picloram-treated sunflower most of the activity was found in the aerial parts, while in picloram-treated rape most of the activity still occurred in the treated leaf after 9 days. No activity at all was found in the roots or in the nutrient solution of the picloram-treated rape seedlings. While the major part of 2,4-D always was found in the state of free herbicide, a large fraction of picloram was rapidly bound into water-soluble complexes. This binding was especially pronounced in rape. Separation by paper chromatography showed that different radioactive compounds were formed. Most of these could be hydrolyzed, thereby releasing free herbicide. The results support the hypotheses that complex formation could counteract herbicide translocation and toxicity of auxin herbicides.     

向日葵分子生物学研究进展

向日葵是一种营养价值极高的资源植物,向日葵的研究和生产在当前我国中西部大开发的战略中具有重要的意义。本文对近年来国内外向日葵分子生物学研究的最新进展,在蛋白质、酶、基因及基因工程、分子标记等方面进行了综述。特别对生化标记、分子标记技术在向日葵研究上的应用及所取得的成果作了重点介绍,并对今后向日葵研究工作进行了展望。     

Phytotoxic effect of oxadiargyl on germination and early growth of sunflower (Helianthus annuus L.) and maize (Zea mays L.)

An attempt was made to assess the phytotoxicity of oxadiargyl on two crop plants, viz. sunflower and maize. The seed germination and early growth studies were carried out in hydroponic conditions with each variety of two crop plants, viz. sunflower (Morden) and maize (NAC-6004) supplemented with five concentrations of oxadiargyl. Seed germination and early growth of both the crop plants were significantly affected with increased concentration of oxadiargyl. The length of radicle and plumule was severely reduced along with increase in herbicidal concentration. Similarly, the calculated value of tolerance index and vigour index decreased drastically with increase in concentration of oxadiargyl. On the contrary, the per cent phytotoxicity also increased with increase in oxadiargyl concentration. Further, the pigment system of both the crop seedlings was severely affected by the herbicide oxadiargyl. These studies clearly indicate that oxadiargyl is phototoxic in nature.     

Stable Expression of Adalimumab in <Emphasis Type="Italic">Nicotiana tabacum</Emphasis>

Production of monoclonal antibodies and pharmaceutical proteins in transgenic plants has been the focus of many research efforts for close to 30 years. Use of plants as bioreactors reduces large-scale production costs and minimizes risk for human pathogens contamination. Stable nuclear transformation of the plant genome offers a clear advantage in agricultural protein production platforms, limited only by the number of hectares that can be cultivated. We report here, for the first time, successful and stable expression of adalimumab in transgenic Nicotiana tabacum plants. The plant-derived adalimumab proved fully active and was shown to rescue L929 cells from the in vitro lethal effect of rhTNFα just as effectively as commercially available CHO-derived adalimumab (Humira). These results indicate that agricultural biopharming is an efficient alternative to mammalian cell-based expression platforms for the large-scale production of recombinant antibodies.     

Genotype peculiarities of crossability of cultivated sunflower with wild species and the use of embryo culture in interspecific hybridization

Peculiarities of the genotype effect of cultivated and wild sunflower species on crossability indices and in vitro hybrid embryonic development have been investigated. It was shown that selection of initial material can considerably influence seed-setting and in vitro embryonic development in the cross group of cultivated sunflower with annual and perennial wild species. The range of plant hybrids obtained through somatic embryogenesis and induction of adventitious shoots was higher in comparison with direct growth of embryos in in vitro culture.