G. Georgiev*, V. Encheva, N. Nenova, Y. Encheva, D. Valkova, P. Peevska, G. Georgiev

Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria

Abstract. The new Bulgarian sunflower hybrid Vokil was developed at Dobrudzha Agricultural Institute (DAI), General Toshevo, Bulgaria by the method of inter linear hybridization. It is a male fertile two-linear hybrid, a cross between line 217 as the mother component possessing cytoplasmic male sterility, and line 340 R, the father fertility restorer component. The two parental lines have very good general and specific combining ability. Hybrid Vokil is early maturing, with growing period of 122 – 125 days, plant height 150 – 160 cm, and head diameter 18 – 21 cm. Seed oil is of linoleic type, and its content is 49 – 51%. Thousand seed weight is 53 – 58 g, the number of seeds per inflorescence is 1180 – 1360, and their weight per plant is 81 – 91 g. The percent of kernel in seed is 72 – 75%. The duration of flowering is 11 – 13 days. The flowering times of the mother and father lines coincide after simultaneous planting, which is a great advantage in the production of hybrid seeds. The planting scheme is 10:2 (mother to father rows) allowing maximum utilization of the area. The father line is taller than the mother line, strongly branched and rich in pollen. Hybrid Vokil went through full approved testing in the breeding fields of DAI. The cross was under control testing for two years, then it was submitted to one-year competitive varietal trial. During the three years of testing the hybrid exceeded the mean standard with 104.9 – 114.9%, the maximum obtained yield being 4570 kg/ha, with oil yield 2344 kg/ha. Oil content in seed reached 51.7%. The official testing of hybrid Vokil was done in Romania for three years, at 10 locations. Averaged for the three years, the seed yield per ha exceeded the mean standard with 3%. Seed yield was within1943–4515kg/haatalllocationsduringthethreeyears,highestresultsaccordingtothisindexbeingobtained inthelastyearoftheofficialtesting– 3635 kg/ha. The mean seed yield from all locations during the entire testing was 3417 kg/ha. In 2013 hybrid Vokil was officially registered in Romania with certificate No 5428/07.08.2013 and was enlisted in the European catalogue of field and vegetable crop varieties.