Investigation on The Effect of Some Plant Growth Regulators on Sunflower (Helianthus Annuus L.)

With a view to establish the effect of some plant growth regulators on sunflower (Helianthus annuus L.) production and oil content was made an experiment. The agricultural test was carried out in the experimental base of Agricultural University of Plovdiv, Bulgaria in 2001-2003. The investigation was pulled out by block design with four replications with crop plot size 20 m(2), previously sowed with wheat. The tested chemicals are as follows plant growth regulators: "H-40'' (alfanaftilvinegar acid), "M-2'' (amid of dicarbonovy acids of benzolovid number), "31''(derivate of naphthalene with auxin efficacy), "XP'' (ftalaminova acid) content micro and macro elements, synthesised in Research Institute of Cryobiology and Food Technology, Sofia in dose 1 cm(3) / l water and Agat 25 EK-2.5 g/da (Too bio biz Ltd.). The investigation was made on Bulgarian sunflower hybrid Super Start, treated during pinhead and flowering. The effect of the tested plant growth regulators on the quantity of yield and some structural elements (sunflower heads number, seeds number, seeds mass, mass/1000 seeds, oil content and oil yield) was reported in the process of investigation. The effect grade of growth regulators is fixed due to non-treated control. By the dispersal analysis method, it is made a mathematics processing of the values of received data. The results of investigation showed that there is no significantly difference between the seed yield kg/da and oil content l/da in pinhead period by the use of plant growth regulators - "31'' (1cm(3)/l water) and "Agat 25 EK'' (2.5 g/da). In the flowering period when treated with the same plant growth regulators, the seed yield is increased as of 15.3 % and the oil content increased as of 16.4% (with Agat 25 EK) but it is decreased as of 18.6% by the application of "31".