RESULTS OF ANALYSIS OF COLLECTION SAMPLES AND HYBRIDS F1 OF WINTER WHEAT FOR RESISTANCE TO LEAF RUST

Abstract

 Winter bread wheat is a precious cereal crop whose grain production is one of the strategic directions of strengthening the Ukrainian economy. However, the yield and quality of cultivated products are significantly influencing by mushroom diseases. Leaf rust (pathogen Puccinia recondita Rob. et Desm. f. sp. tritici) is one of the most common and harmful diseases of wheat, the harmfulness of which is reducing the assimilation surface of plants and increasing their transpiration. This leads to disturbance of water balance, premature death of leaves, decrease of winter resistance and drought-tolerance of plants. Lack of crop due to the strong development of the disease can be 15-20%. The most efficient, cost-effective and environmentally safe method of combating the disease is creating of resistant varieties. Breeding against disease resistance is a very complicated process that requires regular screening of the gene pool, the search for new effective genes of resistance, as well as sources and donors of the indication. Because the races and biotypes of the pathogen are constantly adapting and lead to the loss of resistance to varieties.

The purpose and tasks of the research included the investigation of the genetic diversity of the collection samples of winter bread wheat for the resistance to the pathogen of leaf rust in conditions of artificial inoculation by the causative agent, the formation of a working collection of genotypes for the creation of a new breeding material, as well as the identification of the inheritance characteristics of resistance to the investigated pathogen by the first generation hybrids using a measure of the degree of phenotype domination.

The research was conducted during 2013-2016 in the field infectious nursery of the Plant Protection Department of the V.M. Remeslo Myronivka institute of wheat National academy of agrarian sciences of Ukraine. The collection samples of winter bread wheat were investigated to identifying effective and stable sources of resistance to the leaf rust pathogen and determined the degree of phenotypic dominance in 39 first-generation hybrids based on resistance to this pathogen.

Phenological observations, records and assessments of the stability of collection samples and hybrids were carried out in accordance with generally accepted methods. The indicator of the degree of phenotype domination of the signs of resistance by first-generation hybrids was determined by the formula B. Griffing. Results were grouped according to the classification of G. M. Beil, R. E. Atkins.

Weather conditions of years of research varied according to temperature indices, amount and intensity of precipitation and humidity of air. It influenced the development of plants, and the emergence and spread of wheat brown rust causative agent. Variety - standard of susceptibility Myronivska 10 was affected during the years of research by 10 to 60%

The results of three years of investigation on the artificial infectious background, sources of resistance to the pathogen of leaf rust (Puccinia triticina f.p. tritici Erikss) were identified: Beres (Hungary), IPS-520 (Bulgaria), Tudda 81 (Romania), MV-17 (Hungary), OK 91 P 605, HBE 0425-156, HBE 0140-119, HBE 0303-156, HBE 208-120, Tх91v4511, Tх92v4511, Rochy (USA), Zhitnytsia, Mironivska 30 and Khersonska ostista (Ukraine).

In the forest-steppe area of Ukraine, a high level of stability is protected by known effective genes it has been established: Arthur 71 (Lr9), McNair 2203 (Lr9), Flex (Lr19), Agrus (Lr19), Century (Lr24 + Lr42), TAM-200 (Lr24 + Lr43), Rendezvous (Lr37) and others.

A different nature of the inheritance of this feature was established according to the results of the analysis of F1 hybrids with the use of resistant samples tо leaf rust: overdomination was found in 10.3% hybrid combinations, partial positive dominance – 25.6%, intermediate inheritance – 51.3%, partial negative domination – 10.3% and depression – 2.5% of combinations. The overdominance, in combination with the best manifestation of the sign of resistance to leaf rust, is found in the combinations: НВЕ 0140-119/НВЕ 0303-156, НВЕ 0303 156/НВЕ 208-120, Тх91v4511/НВЕ 0140-119 and NEE 0140-119 / Mironіvska 65.