Methodology for forming a special collection of sunflower lines by adaptability in resistance to diseases

Abstract

The aim and tasks of the study. Theoretical justification of the methodology for forming a collection of sunflower lines by adaptability in resistance diseases to augment the collection fund of the NCPGRU.Results and discussion. The article presents the results of the theoretical justification and expediency of practical application of interval estimates as criteria of a dynamic system for evaluation of immunological characteristics of genotypes in terms of resistance to pathogens of downy mildew (Plasmopara helianthi Novot. f. helianthi), stem canker (Phomopsis / Diaporthe helianthi Munt. –Cvet. et al.) and gray mold (Botrytis cinerea Pers.) on the basis of the year-by-year prevalence of disease, taking into account the influence of weather conditions. A scheme for creating starting material of disease-resistant sunflower was developed as a result of practical application of this system in 2007–2013. Twenty-six sunflower lines - pollen fertility restorers with different combinations of resistance to major diseases were created. The type of adaptability of these lines was determined in relation to the stem canker development intensity. Fifteen lines combining homeostaticity or medium plasticity with a high or medium level of the genotypic effect with respect to stem canker were identified;5 of them (BI 54 V, BI 71 V, BI 77 V, BI 113 V, and BI 131 V) combine homeostaticity (biwithin -0.55 --0.39) and a high level of the genotypic effect (Еіwithin -11,13 - -5,22); 3 lines (BI 11 V, BI 66 V, and BI 127 V) have an medium plasticity (bi = 0,61–1,04) and a high level of the genotypic effect (Eiwithin -18,30--4,13); 6 lines (BI 43 V, BI 47 B, BI 55 V, BI 61 V, BI 72 V, and BI 78 V) are homeostatic (bi within -0,73 - 0,53) with a medium level of the genotypic effect (Eiwithin -2,30-1,22); and 1 line (BI 83 V) is mid-plastic (bi = 1.07) with a medium level of the genotypic effect (Ei = -0.47). Line- pollen fertility restorer BI 20 V is characterized by high resistance to downy mildew and gray mold, high oil content in seeds (31,86 %) and 1000-seed weight of 62,0 g; it is early ripening and multi-calathidium. Line- pollen fertility restorer BI131 V combines high resistance (0,0 % of affected plants) to downy mildew and gray mold, Septoria blight (8 points), and stem canker (22,0 % of affected stemarea), homeostaticity (bi = 0,37), a high genotypic effect (Ei = -9,13) manifested as weak intensity of stem canker development, a large calathidium (22,5 cm), high oil content in seeds (31,87 %) and 1000-seed weight of 87,5 g; it is early ripening and mono-calathidium.Conclusions. Thus, this paper presents the results of the theoretical justification of the methodology for forming of a collection of sunflower lines byadaptatbility in disease resistance. Starting material of sunflower that is resistant to the major diseases was created. Of the lines created, 15 were distinguished, since they combinehomeostaticity, a high genotypic effect manifested as weak intensity of stem canker development and a set of economically valuable traits.The lines were submitted for pre-registration examination at the NCPGRU for subsequent formation of a specific collection of sunflower lines by adaptability in resistance to Phomopsis helianthi.