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The influence of the grafting height (5, 10, 20 and 30 cm above the root collar) of P. edulis on P. gibertii was evaluated on the incidence of Fusarium wilt and horticultural performance. Plants of P. gibertii grafted on P. edulis and non-grafted plants of both species were also studied. In addition, histopathological studies were also performed on the roots of non-grafted P. edulis collected at three severity stages of Fusarium wilt. In greenhouse, the graft take was inversely related to the grafting height in general. In the field conditions, the plant growth of P. gibertii grafted on P. edulis was superior to its reciprocal grafting, even though the former combination was susceptible to Fop. Plants of P. edulis grafted on P. gibertii at all grafting heights did not present symptoms of Fop, and the number of fruit yield and quality were equivalent, but plant growth was decreased in relation to the non-grafted plants. Starch depletion in the root system of P. edulis was directly related to the severity of the Fusarium wilt. P. gibertii was confirmed as a Fusarium wilt resistant rootstock of P. edulis, with minimal influence of the grafting height for the control of the disease.

ABSTRACT:The passion fruit woodiness disease, induced by Cowpea aphid borne mosaic virus (CABMV), is considered the most economically important factor limiting passion fruit production in many countries. This study aimed to assess the progression of symptoms caused by CABMV in different Passiflora species. Eighty genotypes belonging 12 species were evaluated in experiments carried out in a completely randomized block design with treatments arranged in a factorial scheme (80 genotypes x 7 evaluation intervals) considering each inoculated plant as a repetition. The disease severity was estimated by the disease index (DI). The evaluations were performed at 20, 27, 34, 41, 48, 55 and 62 days after inoculation (DAI). The average DI values were used to describe the disease progress at each evaluation interval. The shortest time from evaluation to stabilization of CABMV progress was considered to cluster the genotypes by the ScottKnott test (p≤0.05) and to classify the genotypes as resistant (R), moderately resistant (MR), moderately susceptible (MS), susceptible (S) or highly susceptible (HS). The mean severity gradually increased in the intervals from 20 to 55 DAI and reached a maximum at 62 DAI. The five classes (R, MR, MS, S and HS) contained about 19, 24, 36, 10 and 11% of the germplasm accessions, respectively. The disease temporal progress was quite variable within and among groups, although no difference in DI was observed in the genotypes after 55 DAI, indicating genotype symptom stabilization at this time, regardless of the genotype resistance level.

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O Brasil se destaca entre os cinco maiores produtores de mandioca do mundo, contudo, a produtividade varia no território nacional, devido, dentre outros fatores, a utilização de variedades inadequadas para região, nesse sentido, objetivou-se selecionar cultivares de mandioca nas condições do Recôncavo baiano, em época de colheita com 12 meses. No trabalho foram utilizadas 15 cultivares distribuídas em blocos casualizados com três repetições, avaliando-se sete características agronômicas e a qualidade da farinha. Os dados foram submetidos a análise de variância e multivariada. Pela análise de variância foi observada variação para todas as características com exceção do comprimento da raiz. Produtividade acima de 35,00 t. ha-1 foi registrada para todas as cultivares, com destaque para a cultivar Irará que atingiu 47,00 t. ha-1 e médias superiores para as características agronômicas e de qualidade de farinha, contrariamente às cultivares BRS Tianguá e BRS Jarina. Correlações positivas de alta magnitude foram registradas entre as características de qualidade da farinha, com destaque para as cultivares BRS Amansa burro e 9783/13. As cultivares Irará, BRS Amanso burro e 9783/13 se destacaram para as condições desse estudo, podendo ser utilizadas pelos produtores de mandioca do Recôncavo da Bahia.

The passion fruit woodiness disease (Cowpea aphid-borne mosaic virus – CABMV) causes socioeconomic problems for Brazilian passion fruit crop. Understanding the temporal progress of the disease and identifying resistance sources to CABMV are essential steps to develop resistant varieties. The objective of the study was to evaluate temporal progress of passion fruit woodiness disease, identify Passiflora genotypes with CABMV resistance and to detect virus infection in asymptomatic plants by qPCR. The experiment was conducted in a greenhouse using 128 genotypes belonging to 12 species and three hybrids (inter and intraspecific) of Passiflora evaluated in five periods after inoculation. The symptoms severity was quantified from the disease index (DI%). The CABMV infection in symptomatic plants was confirmed by RT-PCR and in asymptomatic plants by qPCR. Progress rates and disease severity were lower in the species P. cincinnata, P. gibertii, P. miersii e P. mucronata compared to P. edulis, P. alata, Passiflora sp. and hybrids. Of the evaluated genotypes, 20.31% were resistant, with emphasis on the accessions of P. suberosa, P. malacophylla, P. setacea, P. pohlii e P. bahiensis that did not show symptoms of virus. The absence of symptoms does not imply immunity of plants to the virus, as the qPCR analysis confirmed infection by the virus in asymptomatic plants of P. cincinnata, P. gibertii, P. miersii, P. mucronata, P. setacea, P. malacophylla e P. suberosa. Even after four inoculations, the virus was not detected by qPCR in the upper leaves in plants of P. pohlii and P. bahiensis indicating that these species are immune to CABMV.

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