Resistance of sunflower lines and hybrids to major pathogenes in the Northern Steppe of Ukraine

Abstract

The purpose was to establish the manifestation peculiarities of sunflower diseases and their combination with valuable economic traits depending on the genotype, as well as to select the best lines and hybrids for further use in production. To complete this purpose, the following objectives were achieved: to create a stationary infectious background for sunflower; to investigate the manifestation of major diseases of sunflower depending on the year conditions; to assess lines and hybrids for valuable economic characteristics and resistance to several pathogens; to select the best lines and hybrids.

Materials and methods. The phytopathological studies were conducted on a long-term (2005–2020) sunflower monocrop, against artificial field infectious backgrounds, for the creation of which we used parts of naturally infected plants and laboratory infectious material. We studied resistance of sunflower lines and hybrids to pathogens widespread in the Northern Steppe of Ukraine: downy mildew (Plasmopara helianthi Novot.), dry head rot (Rhizopus nigricans Ehrend) and embellisia blotch (Embellisia helianthi (Hansf.) Pidolp). The infectious background level was determined by calculating the percentage of sunflower plants affected by pathogens related to the total number of sown achenes of an accession. The valuable economic characteristics of the genotypes were determined in accordance with the competitive trial methods. A total of 60 accessions, sunflower lines and hybrids bred by IOC NAAS and PPP nd a V.Ya. Yuriev NAAS, were studied.

results and discussion. The infectious background level, defined as the percentage of infected plants, fluctuated over the study years. The variability ranges were as follows: for downy mildew in 2005–2020 – 7.2–27.3%; for dry head rot in 2012–2020 – 47.1–82.2%; for embellisia blotch in 2012–2020 – 11.0–88.8%. A line – sterile analogue (ZL70A), a line – pollen fertility restorer (Kh 114 V) and hybrids (Khazar, Koliada, Pervistok and Pryz) with high (score 7 points) or very high (score 9 points) resistance to the three studied pathogens have been identified. High resistance to downy mildew and dry head rot was recorded in line Kh 720 V and simple sterile hybrid KhZ 1701 A. Lines Skh 1008 A, ZL72A, ZL42A, and ZL260V as well as hybrid Haichur were distinguished due to their high resistance to downy mildew.

During the years of studying valuable economic characteristics (2017–2020), high levels of the infectious backgrounds of the major pathogens of sunflower were observed, which made it possible to identify the best accessions combining high resistance (resistance score 7 and 9 points) with high yield, high 1000-seed weight (up to 58.6 g), high oil content in seeds (up to 52.12%) and low huskness (£ 24.6%). The ‘germination – physiological ripeness’ period in the best resistant hybrids was 95–105 days and, in the lines, it lasted 85–105 days. Hybrid Koliada jointly bred by PPI nd a V.Ya. Yuriev NAAS and IOC NAAS was the best in terms of yield (3.61 t/ha). Since 2020, Koliada has been the State Register of Plant Varieties Suitable for Dissemination in Ukraine.

Conclusions. A possibility of identifying genotypes (lines and hybrids) with group resistance to the major sunflower pathogens, which are common in the Northern Steppe of Ukraine, has been proven. Lines and their hybrids combining high resistance to the major pathogens with high levels of economic characteristics have been identified.