Quick Test for Detecting Glyphosate-Resistant Ryegrass Seeds

ABSTRACT: The commercialization of ryegrass seeds with the presence of resistant biotypes is a serious issue that increses the dispersion of resistance to new areas without this problem. Therefore, this study aimed to develop a quick test to detect susceptible and resistant seeds to the glyphosate herbicide in order to identify contaminated seed lots with glyphosate resistance. Three experiments were carried out, one in greenhouse and the other two in the seed laboratory. First, the resistance factor (RF) was determined by a dose-response curve experiment in biotypes suspected to be resistant and susceptible to glyphosate. Then, the germination test was conducted with the selected biotypes under increasing glyphosate rates (0, 3.5, 6.9, 13.9, 27.8, 55.5, 111, 222, 445, 890, and 1,780 mg a.e. L-1), as the second experiment. The third experiment was made to verify the methodological efficiency of the germination test with glyphosate to identify different contamination ratios (0, 4, 12, 36, and 100%) of the resistant biotype in the seed lot. The different levels of susceptibility of the biotypes to glyphosate were confirmed by the RF of 154.7 based on C50. Germination of the susceptible biotype was inhibited more than 99% by the rate of 127 mg a.e. L-1, while the resistant biotype was a little affected. The germination test with 127 mg a.e. L-1 of glyphosate showed contaminations of 2, 5, 19, 39, and 86% in lots with 0, 4, 12, 36, and 100% of contaminated seeds, respectively. This methodology can detect glyphosate susceptible and resistant seeds and identify contaminated seed lots with resistant glyphosate biotypes.

Fibre-Concrete Tubes in Pure Shear Mode

Fibre-concrete is rapidly developing material, which becomes more widely often used. Strong feature of fibre-concrete is its ability of carrying stress after reaching the ultimate strength. In order to fully understand this material it is necessary to observe its performance in different types of failure. The aim was to create experiment in which the conditions of pure torsion are realized without accompanying by other stress. During testing there will be observed not only the ultimate strength, but also the torque-twist diagram and stress variation on the descending post-peak curve. Experiment of this new character will give results of great importance and will contribute to full understanding of performance of material fibre-concrete.

Design of Labview Based Equipment for Measuring Thermally Stimulated Current

In this paper, we improved the home-made EL experimental set-up, have increased the function of TSC, enable the joint measurement of EL and TSC to measure the trap of shallow and deep. It is significant to study material properties. through the Labview8.6 software programming, the data of temperature and current could be collected, then we can get the curve that the current changes with temperature, it is the TSC curve. Experiment result proved the reliability of laboratory equipment.