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Piracicaba, Brazil

Oliveira I.T.,Federal University of Vales do Jequitinhonha and Mucuri | Lopes C.A.,Embrapa Hortalicas | Moura A.B.,C. Postal
Horticultura Brasileira | Year: 2014

Fruit yield and bacterial wilt symptoms of eggplant genotypes CNPH006, CNPH171, CNPH658, CNPH778, CNPH783, and CNPH785 were quantified in soil naturally infested with Ralstonia solanacearum (race 1, biovar 3) in Brasília, Brazil. Except for CNPH778, all genotypes developed at least one typical wilted plant. Besides wilt, other symptoms considered for assessing levels of tolerance/resistance among genotypes were plant death (CNPH006, CNPH171, CNPH658 and CNPH783), leaf chlorosis (CNPH785) and plant dwarfing (all genotypes). The occurrence of bacterial ooze on cut stems was observed in all plants grown in infested beds, including those that did not exhibit wilt symptoms. Plants grown simultaneously in noninfested beds of the same dimensions and soil characteristics allowed the comparison of yield losses due to the pathogen. The genotypes were grouped according to their ability to maintain fruit production in the infested area. CNPH785 was the most tolerant genotype, with no significant loss due to the disease, followed by CNPH783, CNPH778 and CNPH171, with mean losses of 19.3%, 11.4%, and 10.1%, respectively. The genotypes CNPH658 and CNPH006 were the most susceptible, with average losses of 99.53 and 99.32%, respectively. © 2014 Sociedade de Olericultura do Brasil. All rights reserved.

Ribeiro H.B.,C. Postal | Ribeiro R.C.F.,C. Postal | Xavier A.A.,C. Postal | Campos V.P.,Federal University of Lavras | And 2 more authors.
Horticultura Brasileira | Year: 2012

The exocarp and external mesocarp of pequi fruit are discarded during the extraction of internal mesocarp which is the commercial part used as food. The objective of this research was to study the use of aqueous extract and of pequi ground-powder to the control of root-knot nematode (Meloidogyne javanica). From ground pequi fruit exocarp and external mesocarp were obtained the aquaeous extract and powder. Five doses of aquaeous extract (0.0; 2.5; 5; 10 or 20%) were evaluated on root-knot nematode J2 (second stage juvenile) hatching and mortality. The assays were carried out in entirely randomized design with 10 replications. The hatching assay was set in Petri plates with 800 nematode eggs and 10 mL of different doses of extract. During 14 days we counted the number of hatched juveniles under optical microscope. The mortality assay of root-knot nematode was evaluated putting 100 μL of each dose of extract plus 20 μL of supension containing 20 J2 in each cell Elisa plate. After 24 h was counted the number of live and dead juveniles. The pequi powder was tested in tomato plants in greenhouse in four doses (0; 7.5; 15 or 30 g/4 kg of soil) in randomized blocks design with 10 replications per treatment. The pequi powder was incorporated to the soil seven days before transplanting and nematode eggs inoculation was carried out after transplanting. After 40 days we evaluated the number of galls, egg masses, eggs/root and J2 per 200 cm 3 soil and the tomato shoot dry weight and height. The aquaeous extract reduced J2 hatching and increased J2 mortality. The increased application of powder doses reduced the number of galls, egg masses and eggs of root-knot nematodes per root system and the tomato shoot dry weight being a good indication of phytotoxicity.

Silva P.P.,Embrapa Hortalicas | Freitas R.A.,Embrapa Hortalicas | Cicero S.M.,C. Postal | Marcos-Filho J.,C. Postal | Nascimento W.M.,Embrapa Hortalicas
Horticultura Brasileira | Year: 2014

Obtain pumpkin seeds with high physiological quality is critical for the domestic seed production in terms of competitiveness with imported seeds. One technique that has recently been used to elucidate the various aspects of seed performance is the analysis of images, including those obtained through X-ray. This technique involves X-ray images of seeds to evaluate the internal morphology and to establish the relationship with the seed performance. Thus, the objective of this study was to determine whether the X-ray technique may help to detect internal abnormalities and to assess the quality of pumpkin seeds. 'Brasileirinha' pumpkin fruits were harvested at different maturation stages (30, 40, 50 and 60 days after anthesis). In each stage, seeds were extracted either immediately after harvesting or after 15 days of fruit storage. In the X-ray test, seeds were subjected to an intensity of 25 kV for 40 seconds and then a germination test was carried out at alternate temperatures (20-30°C). The first count was held after four days and the last reading after eight days, computing the percentages of normal and abnormal seedlings and dead seeds. After obtaining the results of the germination test, a comparison of results was done with the images of the internal morphology of each seed, obtained by means of X-ray. The use of X-ray technique is effective in detecting malformed and empty pumpkin seeds and these negatively affect germination.

de Medeiros D.C.,C. Postal | de Medeiros J.F.,C. Postal | de L Pereira F.A.,C. Postal | de M Silva S.C.,C. Postal | das Gracas Amancio M.,C. Postal
Horticultura Brasileira | Year: 2011

Among the problems faced by the melon crop in the state of Rio Grande do Norte, northeastern Brazil, the effect of water and soil salinity is considered one of the key factors to limit fruit production and quality. The aim of this work was to study the effects of using irrigation waters with different salinity levels on yield and quality of fruits of the yellow melon hybrid Mandacaru. A randomized complete block design was used with five treatments (irrigation water salt concentrations: 0.54, 1.48, 2.02, 3.03, 3.9 dS m -1) and four replications. The effects of these concentrations were evaluated through, number of marketable fruits per plant, marketable and total fruit yield, average marketable fruit mass, soluble solids content and pulp firmness. Increment in water salinity level negatively influenced crop yield. The 3.9 dS m -1 salinity level caused yield losses of 20.31%, due to the reduction of fruit number per plant. The highest soluble solid content and the highest pulp firmness values were estimated to occur at salinity levels 2.09 and 3.5 dS m -1, respectively.

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