Métodos de obtenção de novas fontes de resistência à brusone foliar por meio da cultura de tecidos em arroz (oryza sativa)

• Ano de defesa: 2018
• Autor(a) principal: Alves, Lays Lohanne
• Orientador(a): Araújo, Leila Garcês
• Banca de defesa: Araújo, Leila Garcês, Lobo, Válacia Lemes da Silva, Castro, Adriano Pereira de, Guedes, Márcio Lisboa
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Genética e Melhoramento de Plantas (EA)
• Departamento: Escola de Agronomia - EA (RG)
• País: Brasil
• Palavras-chave em Português: Cultura de anteras; Variação somaclonal; Resistência genética; Magnaporthe
• Palavras-chave em Inglês: Anthers culture; Somaclonal variation; Genetic resistance; Magnaporthe oryzae
• Área do conhecimento CNPq: FITOTECNIA::MELHORAMENTO VEGETAL
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/9870

Rice (Oryza sativa L.) is the staple food of more than half of world's population. The productivity in all cropping systems is affected by the blast (Magnaporthe oryzae), the main rice disease, can cause losses of up to 100% depending on climatic conditions and the virulence of the pathogen. Obtaining new sources of blast resistance is very important for the management of this disease. Double haploid populations allow acceleration of lineage fixation as allows homozygotes to be achieved in just one generation. Somaclonal variation is another tissue culture technique successfully used for the induction of blunt mutations. The objective of the present work is to obtain new sources of resistance to leaf blast in populations of double haploids and somaclones. For this, callus induction and plant regeneration were performed from the anthers of BRS Primavera x CNA 923 and immature panicles of the cross between the cultivars Metica-1 and Cica- 8.In a greenhouse, R2 plants were inoculated with the IB-1 and IB-45 pathotypes of Magnaporthe oryzae, from the cultivars Metica-1 and Cica-8, respectively. For each pathotype a population of 800 plants was used. On the seventh day after inoculation, leaf blast severity was evaluated using the scale of scores ranging from 0 to 9, with a score of 0 to 3, representing resistance reactions and 4 to 9, susceptibility reactions. The severity of the blast was evaluated in a population of 50 plants on generation R2 somaclones with each parent (Metica-1 and Cica-8) and their respective M. oryzae races (IB-1 and IB-45). For severity, four evaluations were performed at 48-hour intervals to calculate the area below the disease progress curve (AACPD). The data were submitted to the T test in the SPSS program. Of a total of 800 plants inoculated with the IB-45 breed, 644 plants were resistant and 156 showed susceptibility reactions. For the IB-1 breed, 664 resistant and 136 susceptible R2 plants were obtained, indicating the induction of genetic variation in relation to leaf blast resistance in the initial generations. The T-test showed a significant difference in the severity of blast between the parents and the somaclones, with a mean of 32.96% for the Metica-1 cultivar and 3.36% for the somaclones inoculated with the IB-1 breed, and 34,24 % for the cultivar Cica-8, in contrast whit 7.59% for the somaclones inoculated with the IB-45 breed. There was a significant reduction of the AACPD, with a mean of 56.76% for Metica-1 and 6.22 for the somaclones inoculated with the IB-1 race and 66.83% for the Cica-8 and 12.1 for the somaclones inoculated with the IB -45. There was a significant the somaclones inoculated with the two races, demonstrating that somaclonal variation produces sources of resistance to the pathogen. The R2 plants that presented resistance reaction to the two races were selected and transplanted for generation advance aiming at new sources of blast resistance, thus contributing to the rice breeding program.