Evaluation of the sunflower samples collection of the All-Russian Institute of Plant Genetic Resources (VIR) by economically valuable traits in the Azov zone of the Rostov region

An all-round overcrowding of a crop rotation with sunflower sowings caused the accumulation of infectious matters of many diseases affecting this crop in agrocoenoses and the appearance of the more virulent races of the pathogens. There are reports on infestation of sunflower sowings by a rust pathogen Puccinia helianthi Schwein. The studying of the race composition showed the presence of more aggressive races. This required for the development of sunflower breeding material resistant to the wide spread races of this pathogen. The sunflower collection of the All-Russian Institute of Plant Genetic Resources (VIR) contains samples being the sources of resistance to rust. We studied valuable for breeding traits of 57 sunflower samples. The works were conducted on fields of the Don experimental station according to the methods developed in the V.S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK). A level of susceptibility to rust was determined due to the 5-point scale by Melchers and Parker. The samples belonged to four maturity groups, among them the early maturing samples prevailed. A plant height varied from 80 to 240 cm depending on a genotype. These data certifies the studied samples can be used in crosses to develop new parent material. Excessive precipitations at the end of July and at mid-August conditions the huge spreading of rust pathogen in sunflower sowings. A level of infection was maximal in July - August. The sunflower samples from the collection divided by susceptibility to rust pathogen as following: five ones had maximal level of infection of 4 points, eight samples - 3 points, five ones - 2 points, 29 ones - 1 point, ten samples were not infected. The samples from the collection with had no symptoms of disease can be used in breeding to develop parent material resistant to rust pathogen on sunflower.