[en] Tests with the lucerne varieties Pleven 1, Dounavka and Du Puits are carried out in 1967-1973 at the Forage Institute, Pleven. Air dried seeds of the above varieties were irradiared at 500 - 2000 R. Under the experimental conditions the doses Co⁶⁰ and Cs¹³⁷ did not substantially affect the seed germination, rate of growth, initiation of more important phenophases, dry matter yield and its protein content. Some stimulating effect was observed regarding the seed yield. The same is expressed as a complex interaction between the radiation source, irradiation dose, variety, duration of irradiated seed storage and weather conditions during the growing season of the lucerne crop. The gamma rays Co⁶⁰ and Cs¹³⁷ exert a strongest stimulating effect on the number of flowers and pods per plant and number of seed per pod. A quantitative change of these indices corresponds to the seed yield. A stimulating effect is more strongly manifested on crops grown from seeds stored for three years and in growing seasons with more favourable conditions for seed production. A dose of 1000 R shows highest stimulating effect at irradiation of previous year seeds of the Dounavka variety (most widely distributed in Bulgaria) with Cs¹³⁷. The gamma-rays doses studied did not show a stimulating effect at pre-sowing treatment of previous year seeds of the Du Puits lucerne variety. (author)

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[en] The study was carried out at the experimental base of the Fodder Institute of Feeds, Pleven, with alfalfa cv. Pleven 6 in three field trials. The effect of pre-sowing gamma-irradiation (Cs-137) of air dry seeds at rates of 1000, 1300 and 1600 R on the yield produced was studied in the first trial (1980-1982). The effect of pre-sowing gamma-irradiation (Cs-137) of the seeds on seed production was studied in the second trial. Gamma-ray doses of 500, 1000 and 1500 R and three sowing rates (3, 5 and 10 kg/ha) were tested. The after effect of gamma-irradiation on the progeny was studied in the first trial (1981-1982). It was found that the treatment tested had a stimulating effect on seed production yields. Highest stimulating effect for the period of investigation, on the average, was observed with the 1500 R dose and the 3 kg/ha sowing rate. The same treatment produced highest net income. The gamma-ray doses tested had no radiation after-effect on the plant progeny. Sowing rates had a considerable effect on seed yield. In this respect the 3 kg/ha rate surpasses the 5 and 10 kg/ha rates by 6.00 and 19.64%, on the average. The 1000, 1300 and 1600 R gamma-ray doses had no stimulating effect on fodder yield

[en] The 20-cm radio continuum fluxes of 91 HII regions in a previously compiled catalog have been determined. The spectral types of the ionizing stars in 42 regions with known distances are estimated. These spectral types range from B0.5 to O7, corresponding to effective temperatures of 29 000–37 000 K. The dependences of the infrared (IR) fluxes at 8, 24, and 160 μm on the 20-cm flux are considered. The IR fluxes are used as a diagnostic of heating of the matter, and the radio fluxes as measurements of the number of ionizing photons. It is established that the IR fluxes grow approximately linearly with the radio flux. This growth of the IR fluxes probably indicates a growth of the mass of heated material in the envelope surrounding the HII region with increasing effective temperature of the star.