Métodos de obtenção de novas fontes de resistência à brusone foliar por meio da cultura de tecidos em arroz (oryza sativa)
Nenhuma Miniatura disponível
Data
2018-12-10
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
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.
Descrição
Palavras-chave
Citação
ALVES, L. L. Métodos de obtenção de novas fontes de resistência à brusone foliar por meio da cultura de tecidos em arroz (oryza sativa). 2018. 51 f. Dissertação (Mestrado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2018.