YIELD AND ADAPTIVE CAPACITY SUNFLOWER VARIETIES AND HYBRIDS
According to the analyzed complex of adaptive properties of sunflower in the conditions of the Bryansk region the varieties under study Skormas, P 453 and the hybrids Sprint, Avangard and Fakel were characterized with a various spectrum of adaptive reactions. Of all the varieties and hybrids studied, the hybrid Sprint showed the highest responsiveness to the changes in the yield due to the external cultivation conditions (b<sub>i</sub>=6.809). The variety Skormas weakly responds to the changes in growing conditions. There was a close correspondence between the change in growing conditions and the yield shifts of the hybrid Avangard (b<sub>i</sub>=-0.024) and the variety P 453 (b<sub>i</sub>=-0.055). The hybrids Fakel (Ca=1.54) and Sprint (Ca=1.03) had the uppermost adaptability coefficient (Ca), while the values of the varieties P 453 (Ca=0.85), Skormas (Ca=0.82), and the hybrid Avangard (Ca=0.75) were not high. Over the research years the middle-early hybrid Fakel was distinguished with the highest yield (5.28 t/ha), adaptability and stress resistance. It is characterized with an average-sized tilted head, a black-coloured achene with a fat content of 43.8-44.6% on average. As for the production conditions, the middle-early variety Skormas is of interest, with the growing season being 115-120 days, the thousand-seed weight - 45.5 g, the yield - 2.81 t/ha with a seed fat content of 47.7%. The variety is resistant to white rot and mildew. In the field it was slightly affected by gray and dry rot and rust, middling - by phomopsis. Like Skormas, the early-maturing, non-branching variety P 453 has got a seed yield of 2.91 t/ha with a fat content of 47.5%. The plant of an early-maturing single-cross hybrid Sprint is characterized with an average height. The sunflower head, from medium to large in size, is turned downwards with a heavily curved stem, the shape of the seed disc is flat. The yield is 3.57 t/ha with a fat content of 43.5%. Sprint is moderately resistant to mildew and white rot. In the field it is weakly affected by gray rot, phomopsis and rust, and middling - by broomrape. The three-cross early-ripening hybrid Avangard showed an average yield of 2.58 t/ha with a fat content of 54.5%.