Evaluation of genetic resistance to brusone in wheat grown in Brazil

Maria Luiza De Grandi, journalist from Ciência Rural, Santa Maria RS, Brazil.

João Nunes Maciel, research of Empresa Brasileira de Pesquisa Agropecuária, Passo Fundo, Rio Grande do Sul, Brazil.

Wheat blast is a disease caused by the fungus Pyricularia oryzae Triticum (PoT) and its most common symptom is the bleaching of part of the ear from the point of infection. The first report of wheat blast in the world was in Brazil, in 1986. Since then, a great effort has been made with a view to developing wheat cultivars resistant to this disease.

Researchers from the Brazilian Agricultural Research Corporation (Embrapa), in partnership with the Federal University of Santa Maria (UFSM) and the University of Passo Fundo (UPF), evaluated the resistance of wheat genotypes to blast and verified the correlation between disease severity in spikes and PoT sporulation rate in spike rachis. The article Resistance of Brazilian wheat cultivars to blast under controlled conditions was published in Ciência Rural (vol. 52, no. 7).

The research gathered more than 40 Brazilian wheat cultivars grown in pots, at the flowering stage (stage 65 on the Zadoks scale). The methodology used to reach the objectives was the evaluation of the reaction of wheat cultivars to the infection of the fungus PoT, under controlled conditions. Temperature, humidity and photoperiod were controlled during the process of plant infection by the fungus. After 5 and 7 days of inoculation of the pathogen in the plants, the severity of the disease was evaluated in the ears, and then, the ears were harvested and the spikelets removed. Subsequently, the pathogen sporulation rate was measured in the rachis in the phytopathology laboratory at Embrapa Trigo.

Image: Pixabay.

According to Embrapa Wheat researcher João Leodato Nunes Maciel, the research pointed to two important results: the updated characterization of the reaction to blast of wheat cultivars that are currently frequently used in Brazil and the evaluation of a new parameter as a criterion to characterize wheat genotypes. wheat for reaction to blast, which is the determination of the rate of sporulation of PoT in rachis of ears of wheat.

“The lack of correlation between blast severity on ears and the production of PoT conidia, as observed in the study, should not be considered as a definitive result that there is no connection between these two types of variables in the wheat pathosystem – PoT.”, emphasizes the researcher. This is the first report on the use of the sporulation rate of this fungus in wheat plants as a criterion to evaluate and compare the reaction of wheat cultivars to blast.

In practice, the research results can be used as a source of information for rural producers who grow wheat in Brazil. “It will be useful for them when deciding which cultivar to adopt in their crops, considering that they are interested in cultivars that are more resistant to blast”, explains João.

References

TORRES, G.A.M., et al. Blast disease and wheat production in Brazil. Pesq. agropec. [online]. 2022, vol. 57, e02487 [viewed 13 February 2023]. https://doi.org/10.1590/S1678-3921.pab2022.v57.02487. Available from: https://www.scielo.br/j/pab/a/GfBqSnSYY6L3dGwjVBj98cD/

To read the article, access

MACIEL, J.L.N., et al. Resistance of Brazilian wheat cultivars to blast under controlled condition. Cienc. Rural [online]. 2022, vol. 52, no. 7, e20210417 [viewed 13 February 2023]. https://doi.org/10.1590/0103-8478cr20210417. Available from: https://www.scielo.br/j/cr/a/ZPScp6gT4Yk8bvKZDQGLm4p/

External links

Ciência Rural – CR: https://www.scielo.br/cr/

Ciência Rural – site: http://coral.ufsm.br/ccr/cienciarural/

Redes Sociais: Twitter | Facebook | Instagram