Reação de variedades de maracujazeiro amarelo (Passiflora edulis Sims f. flavicarpa Deg) a bacteriose causada por Xanthomonas campestris pv. passiflorae. / Reaction of varieties of yellow passion fruit (Passiflora edulis Sims f. flavicarpa Deg.) to bacterial spot caused by Xanthomonas campestris pv. passiflorae.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

This study aimed to evaluate the reaction of eight populations of commercial yellow passion fruit and two of wild passion fruit (P.edulis Sims f. flavicarpa) to Xanthomonas campestris pv. passiflorae and elaborate a diagrammatic scale of symptoms for the evaluation of the severity of the disease. This scale was developed based on 100 leaves with different levels of disease. Out of this sample, five levels of severity were depicted in the scale (2%, 5%, 11%, 26%, and 59%). The scale was used by seven evaluators to assess the symptoms of 48 leaves with different degrees of severity. The evaluators showed high precision judging by the high correlation coefficients (R2) which ranged from 0.86 to 0.95. Most evaluators showed a tendency to super-estimate the severity of the disease. Notwimstanding, the scale allowed precise and accurate evaluations. Two experiments were performed in the greenhouse to determine the level of resistance of ten populations (eight commercial and two wild) of yellow passion fruit to X. campestris pv passiflorae. The first trial was conducted between September and December 2002, and the second between January and March 2003. The experimental design consisted of random blocks, with nine treatments and four replicates in both experiments. The experimental plot consisted of 30 and 25 plants of each variety, respectively in the first and second trials. Disease severity was evaluated 7, 14, and 21 days after inoculation using the diagrammatic scale. With the data of the three evaluations, the area under the disease progress curve (AUDPC) for each material was estimated and used in the analysis of variance. The results detected different levels of resistance among populations. The most resistant materials were the varieties Sul Brasil and IAC- serie 270, while the varieties IAC-277, Maguary e Flora were the most susceptible.

ASSUNTO(S)

mancha bacteriana resistência genética vegetal genetic resistance maracujá amarelo passion fruit bacterial spot bacterial disease xanthomonas xanthomonas bacteriose vegetal

ACESSO AO ARTIGO

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