IMPACT OF THE PRE-SOWING IRRADIATION OF SEEDS BY HELIUM-NEON LASER ON THE DYNAMICS OF DEVELOPMENT OF SOME COTTON VARIETIES

The experiment was carried out at the experimental field of the Agricultural University - Plovdiv, Department of Crop Production in 2002-2004 with cultivars Bely izvor, Chirpan 539 and Avangard. The seeds were irradiated using helium-neon laser of 623.8 nm wavelength and power 20 mW. The average duration of seed treatment in the irradiation zone was 1x10(-3) s and the mean single irradiation doze - 3x10(-7) s. The seeds were irradiated 4, 6, 8 and 10 times. Untreated seed were used as control (C). The randomised complete block design at 4 replications and 25 m(2) plot size was used. The aim of the study was to determine the influence of pre-sowing cotton seeds irradiation by helium-neon laser on the development and flowering of plants. Helium-neon laser pre-sowing irradiation of cotton seeds did not influence the proceeding of plant development stages. A stimulation effect has been found on the rate of growth of high stem of plants and flowering dynamic of testing cultivars. Highest stimulating effect of the three-year experiments was obtained by 8 times treated seeds. The rate of growth of high stem of plants and flowering dynamic of testing cultivars was highest of irradiated variants.