Resistance to stem canker, frogeye leaf spot and powdery mildew of soybean lines lacking lipoxigenases in the seeds

Autor: Martins Carlos Alberto Osório, Sediyama Carlos Sigueyuki, Oliveira Maria Goreti de Almeida, Reis Múcio Silva, Rocha Valterley Soares, Moreira Maurílio Alves, Gomes José Luiz Lopes
Jazyk: English<br />Spanish; Castilian<br />Portuguese
Rok vydání: 2002
Předmět:
Zdroj: Scientia Agricola, Vol 59, Iss 4, Pp 701-705 (2002)
Druh dokumentu: article
ISSN: 0103-9016
1678-992X
Popis: The soybean [Glycine max (L.) Merrill] crop holds a prominent position in the Brazilian economy because of the extension of the planted area and volume of grain production, but the beany flavor has been a limiting factor for soybean derivatives consumption by western population. This flavor is produced mainly by action of lipoxygenase enzymes (Lox1, Lox2 and Lox3), present in some commercial varieties. The genetic elimination of the alleles that codify these enzymes is the most appropriate way to avoid problems associated to this deleterious flavor. To elucidate the effect of seed lipoxygenase elimination on the resistance to plant pathogens, normal varieties of soybean (FT-Cristalina RCH, Doko RC and IAC-12) and their backcross-derived lines, both with the three lipoxygenases present in their seeds (triple-positive, TP) and without the three lipoxygenases (triple-null, TN), were tested for their resistance to stem canker (Diaporthe phaseolorum f.sp. meridionalis), frogeye leaf spot (Cercospora sojina Hara), and powdery mildew (Microsphaera diffusa Cke. & Pk.). All genetic materials studied were resistant to stem canker. FT-Cristalina RCH and Doko-RC and their TP and TN lines were resistant to frogeye leaf spot. IAC-12 and its derived lines not only presented a higher disease index, but also the derived lines, TP and TN, were more susceptible, indicating the loss of genes for disease resistance in the backcrosses. There was no association between the elimination of lipoxygenases from the seeds with the resistance to frogeye leaf spot. In relation to the powdery mildew, TP or TN lines presented similar or higher resistance than their respective recurrent parents whose susceptibility appeared in the following order: IAC-12, less susceptible, Doko-RC, intermediate and FT-Cristalina RCH, more susceptible.
Databáze: Directory of Open Access Journals
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