Bulgarian common wheat cultivars released in the period 1925-2003 were studied using the gibberellic acid (GA) test and microsatellite analysis of the Xgwm261 locus on chromosome 2DS to identify the semi-dwarfing (Rht) genes. The old cultivars, isolated through selection from landraces, carried rare alleles (211-and 215-bp) at Xgwm261 locus, and those developed by hybridisation to foreign cultivars, carried the 165-and 174-bp alleles. Forty-two (55.3%) of 76 modern cultivars were GA-responsive. The 192-bp allele, diagnostic for Rht8, was observed in 64 (84.2%) modern cultivars, of which 37 carry Rht8 alone, and 27 possess a combination of Rht8 and a GA-insensitive allele viz. Rht-B1d (17); Rht-D1b (6) and Rht-B1b (4). The 174-bp allele is present in seven cultivars, only one of which is photoperiod-sensitive, and the rest are day-length insensitive. The 203-bp allele was found in six modern cultivars. Cultivars carrying the Rht8 allele are the most widespread and some of them have been cultivated for a long period. Cultivars with the 'Saitama 27' allele (Rht-B1d) are the most productive and are second in distribution in the country. The recently observed trend for increasing the proportion of cultivars with GA-insensitive Rht genes is probably due to their combination with the 192-bp allele of Xgwm261 locus tightly linked to the Ppd-D1, to the break of the link between the 174-bp allele and ppd-D1, and to the introduction of other genes influencing flowering time.

A capacitive radiofrequency (RF) discharge at atmospheric pressure is studied by means of a time-dependent, two-dimensional fluid model. The plasma is created in a stationary argon gas flow guided through two perforated electrodes, hence resembling a shower. The inner electrode, the electrode facing the flow entrance, is powered with a frequency of 13.56 MHz, and the outer electrode is grounded. The model solves the mass balance equations for the relevant active species and the electron energy balance equation in conjunction with the Poisson equation for the field sustaining the plasma. The mass balance equations of the active species are calculated using the drift–diffusion–convection approach, thus taking the bulk velocity into account. The velocity field is calculated with the Navier–Stokes module of the Plasimo toolkit. The plasma dynamics is studied in three connected regions; the space between the electrodes, the regions before the powered electrode and the extended region behind the grounded electrode. The effect of the shower holes and the recirculation gas flow on the plasma is examined.

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Surface-wave-sustained discharges (SWDs) can operate across a wide range of discharge conditions. From low to atmospheric pressure, plasma sustained by travelling electromagnetic wave is strongly non-equilibrium: the electron energy distribution function (EEDF) is non-Maxwellian; the gas temperature T g (the translational temperature of the heavy particles) is much lower than the electron temperature T e , i.e. T g T e . In this paper, kinetic models of surfacewave-sustained argon plasma based on the Boltzmann equation and its momenta are presented for various discharge conditions (intermediate and high gas pressure and various discharge tube radii). The difference between the models is in the energy level diagrams and the elementary processes taken into account for the various conditions. The models give the EEDF, transport and rate coefficients, mean electron energy, electron-neutral collision frequency for momentum transfer, mean power required to sustain an electron-ion pair in the discharge, and densities of considered atomic and molecular species as a function of the electron density n e . Since the surface-wave plasma is spatially inhomogeneous, all these plasma characteristics change along the plasma column in the axial direction as the wave power absorbed by the electrons and electron density change. The goal is to compare the results obtained from the models with the experimental data and to determine their applicability depending on the SWD conditions.

This paper resolves a long standing discrepancy between theoretical modeling of atmospheric microwave plasma jets and their diagnostics by Thomson scattering. The discrepancy is found to be created by the filamentary behavior of the plasma.