YIELD COMPONENTS AT SOME HYBRIDS OF SUNFLOWER (Helianthus annuus L.) UNDER DROUGHT CONDITIONS FROM SOUTH ROMANIA

Sunflower (Helianthus annuus L.) is the most important oil crop in Romania. The grain yield is determined by the yield components, respectively those elements participating to the yield formation, such as: plant population (number of plants per hectare), head diameter (cm), number of grains per head, grain weight per head (g), weight of thousand seeds (g). Water deficit is considered to be an important yield-limiting factor of sunflower. However, sunflower is considered to be a crop well adapted to drought conditions, better adapted than maize. The aim of the paper was to present the results regarding yield components and grain yield obtained at an assortment of Romanian sunflower hybrids studied under drought conditions from South Romania. Also, it was aimed to evaluate the impact of drought on the sunflower yield components and grain yield compared to those values obtained under favourable conditions. The study was realised under field conditions in the year 2012, which was characterised as being a drought year. Researches were performed at an assortment of ten sunflower hybrids created in Romania, respectively: PRO 112, PRO 111, PF 100, PRO 229, PRO 121, PRO 122, PRO 131, PRO 132, PRO 141, and PRO 142. The study was implemented in three different locations in South Romania. Under drought conditions of 2012, the most affected yield component at the studied sunflower hybrids was head diameter. Compared to values obtained in favourable climatic conditions, in average for the studied sunflower hybrids the grain yield represented 70.0%. Under the same conditions, in average for ten maize hybrids, the grain yield represented only 37.8% from the values obtained under favourable climatic conditions. This is showing that sunflower is a better adapted crop to water stress than maize.