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Search Results: 1 - 10 of 84652 matches for " PEIXOTO JOSé RICARDO "
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Incidência de injúrias mecanicas em raízes de mandioquinha-salsa na cadeia de pós-colheita
Souza, Roberto Marques;Henz, Gilmar Paulo;Peixoto, José Ricardo;
Horticultura Brasileira , 2003, DOI: 10.1590/S0102-05362003000400029
Abstract: size and appearance are the most important quality characteristics of arracacha roots. the aim of this experiment was to determine the main types and the incidence of mechanical injuries in arracacha roots and evaluate its incidence at the different stages of the postharvest handling system used in brazil. evalution was carried out during five steps of the postharvest handling system (after harvest; packinghouse, before and after washing; wholesale and retail markets) were verified. at each step, 110 roots were taken at random in ten samples (replications) at different places during march 2000 to june 2001. four main types of mechanical damage were identified in arracacha roots: abrasion; partial rupture; splitting; and break. superficial lesions caused by abrasion were the predominant mechanical injury and showed great variation, so an abrasion rating scale (1=no lesion; 5=>40% of lesions) was used. increasing levels of abrasion were recorded as the arracacha roots flowed through the postharvest chain, reaching 13.3% of the roots at the farm; 19.7% before washing and 24.9% after washing at the packinghouse; 47.2% at the wholesale market; and 78.9% at the retail market. the incidence of other types of mechanical damage was higher at the wholesale market (7.6% of rupture, 4.2% of spliting, 10.6% of broken roots). the critical point for the incidence of mechanical damage at the postharvest chain occurred between the packinghouse and the wholesale market, probably due to inadequate packing in wooden boxes and rough handling.
Avalia??o de linhagens, híbridos F1 e cultivares de piment?o quanto à resistência a Meloidogyne spp.
Peixoto, José Ricardo;Maluf, Wilson Roberto;Campos, Vicente Paulo;
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999001200013
Abstract: with the purposes of evaluating f1 hybrids of sweet pepper, together with their parents, for resistance to meloidogyne incognita (races 1, 2, 3 and 4) and m. javanica nematodes, an experiment was conducted in glasshouse conditions in the facilities of pioneer sementes ltda, in ijaci, mg, brazil. a randomized block in split-plot design was used with five plots, composed of four races of m. incognita and one isolate of m. javanica, and 48 subplots, composed of 47 genotypes of sweet pepper and one cultivar of tomato (angela gigante i-5100) as a standard check. five replicates and eight plants in each subplot were used. inoculation was done with 60 eggs/ml of substrate mixture of vermiculite, pinus sp. bark and carbonized rice husk. after 60 days following inoculation, the evaluations were performed. all the cultivars and standard-lines (line 004 and line 006) were susceptible to the races 1, 2, 3 and 4 of m. incognita. all the genotypes of sweet pepper were resistant to m. javanica. almost all of the experimental lines were proved to be resistant to all of the four races of m. incognita. the same occurred to most of the experimental hybrids f1, although the degree of resistance of the hybrids in general was lower than that of their respective resistant parents. it is thus proven to be feasible to utilize f1 hybrids by crossing resistant to susceptible sweet pepper lines to control the nematodes m. incognita and m. javanica through varietal resistance.
Incidência de injúrias mecanicas em raízes de mandioquinha-salsa na cadeia de pós-colheita
Souza Roberto Marques,Henz Gilmar Paulo,Peixoto José Ricardo
Horticultura Brasileira , 2003,
Abstract: O tamanho e a aparência das raízes de mandioquinha-salsa s o os principais atributos de qualidade na comercializa o, e os danos mecanicos diminuem sua durabilidade e valor como mercadoria. O objetivo deste trabalho foi caracterizar e avaliar a incidência de injúrias mecanicas em raízes de mandioquinha-salsa em cinco etapas do manuseio pós-colheita, dividido em colheita, beneficiamento (antes e após a lava o), atacado e varejo. A etapa da colheita foi avaliada em Castro(PR), o beneficiamento nas lavouras de Tapiraí(SP), atacado na CEAGESP(SP) e o varejo em supermercados da grande S o Paulo. Em cada etapa foram selecionadas ao acaso 110 raízes, em dez amostragens (repeti es) em locais e épocas diferentes, entre mar o/2000 e junho/2001. As injúrias mecanicas foram categorizadas em quatro tipos principais: abras o, ruptura parcial, rachadura e quebra das raízes. Como as les es superficiais causadas pela abras o apresentaram grande varia o na extens o dos danos, foi elaborada uma escala de cinco notas (1=sem les o; 5=>40% superfície lesionada) para facilitar a avalia o. As les es superficiais causadas por abras o foram o tipo de injúria mecanica com maior incidência em todas as etapas do manuseio, sendo 13,3% no produtor, 19,7% nas raízes sem lavar, 24,9% nas raízes lavadas, 47,2% no atacado, chegando a 78,9% no varejo. O atacado foi a etapa em que constatou-se a maior incidência de outros tipos de injúrias (ruptura, 7,6%; rachadura, 4,2%; quebra, 10,6%). O ponto crítico para a incidência de injúrias mecanicas ocorreu entre as etapas beneficiamento-atacadista, provavelmente devido à embalagem (caixa de madeira do tipo "K") e ao transporte inadequados.
Herdabilidade e correla??es genotípicas entre caracteres de folhagem e sistema radicular em famílias de cenoura, cultivar Brasília
Alves, José Carlos da S;Peixoto, José Ricardo;Vieira, Jairo V;Boiteux, Leonardo S;
Horticultura Brasileira , 2006, DOI: 10.1590/S0102-05362006000300019
Abstract: the present work was conducted aiming to estimate genetic parameters associated with traits of importance to carrot breeding, including: number of leaves per plant (nl), length of the longest leaf in the plant (ll), root length (rl), root weight (rw), root diameter (rd), and xylem diameter (xd). this experiment was carried out during the rainy summer season (1999/2000) using 69 half-sib families derived from cultivar brasília. progenies were evaluated using a complete randomized block design with two replications and 2 m2 plots, with four 20-plant rows. the broad-sense heritability (ha2) values ranged from 29.9% (for rd) to 77.6% (for ll). genotypic, phenotypic, and environmental correlations displayed a large variation in magnitude with the highest genotypic correlation (0.85) being observed between the traits rw and rd. negative genotypic correlation was observed between rl and xd, which indicates that the development of new cultivars suitable for processing as baby-carrots is feasible using populations derived from cultivar brasilia. high negative environmental correlation values were obtained between the traits rw and xd, as well as between rd and xd. this information would be of extreme importance aiming to optimize the selection process when using segregating populations derived from the tropical-adapted cultivar brasilia.
Danos causados pelo impacto de queda na qualidade pós-colheita de raízes de mandioquinha-salsa
Henz, Gilmar Paulo;Souza, Roberto M.;Peixoto, José Ricardo;Blumer, Lucimara;
Horticultura Brasileira , 2005, DOI: 10.1590/S0102-05362005000400004
Abstract: arracacha roots are very fragile and susceptible to mechanical damage. the postharvest handling system may cause many lesions, mainly by impacts and drops. the effect of drop impact on arracacha roots was simulated in two drop heights (45 and 90 cm) and three release positions of the roots (horizontal, vertical distal and vertical proximal). the experiment was carried out in a randomized block design, with three replicates (40 roots per and three release positions of the roots (horizontal, vertical distal and vertical proximal). the experiment was carried out in a randomized block design, with three replicates (40 roots per parcel). after the drop, roots were examined individually and the resulting mechanical damage was categorized in four types of lesions (broken, fracture, rupture and abrasion) compared to those apparently undamaged. drop height affected directly the incidence of more serious mechanical damage, such as broken roots and ruptures. the root position also affected the resulting mechanical damage: roots released from the proximal position at 90cm drop height had significantly higher fractures incidence (40.7%), ruptures (19.2%) and superficial lesions (22.3%) than other treatments. at the 90 cm drop height, roots released from the proximal position had 40.7% of fractures, 19.2% of ruptures and 22.3% of superficial lesions; roots released from the distal position caused 45.8% of ruptures and 23.3% of broken roots. the respiration rates and deterioration of arracacha roots submitted to mechanical damage (90 cm height fall impact) and storage (5oc and 24oc) during four days showed that at the same temperature, mechanically damaged roots had higher respiration rates when compared to sound roots, ranging from 15.3 ml co2 kg-1 h-1 (unbruised) to 34.4 ml co2 kg-1 h-1 (damaged) at 24oc. injured roots kept at 24oc had 84% of deterioration after four days, while those kept at 5oc were completely sound.
Utiliza??o de compostos organicos como substratos na produ??o de mudas de hortali?as
Leal, Marco Antonio de A;Guerra, José Guilherme M;Peixoto, Ricardo TG;Almeida, Dejair L de;
Horticultura Brasileira , 2007, DOI: 10.1590/S0102-05362007000300014
Abstract: the viability of the organic compost utilization as a substrate for vegetable seedlings production, obtained from crotalaria juncea l. and napier grass (pennisetum purpureum schum.), was determined. the research was developed with lettuce (leaf vegetable), beetroot (root vegetable) and tomato (fruit vegetable). the organic composts were produced from: 100% crotalaria juncea; 66% crotalaria juncea + 33% napier; 33% crotalaria juncea + 66% napier; 100% napier; 33% crotalaria juncea + 66% napier, inoculated with 5% of the mass with cattle manure; 33% crotalaria juncea + 66% napier, inoculated with 100 l of 5% diluted agrobio; 100% napier, inoculated with 100 l of 5% diluted agrobio. we evaluated the height, leaf number, aerial green weight and aerial dry weight. a commercial substrate plantmax ht? was used as control. the compost produced from the mixture of 66% crotalaria juncea and 33% napier presented the best results, being adequate for the production of lettuce, beetroot and tomato seedlings.
Cultivo de brócolos de inflorescência única no ver?o em plantio direto
Melo, Raphael Augusto de C e;Madeira, Nuno R;Peixoto, José Ricardo;
Horticultura Brasileira , 2010, DOI: 10.1590/S0102-05362010000100005
Abstract: the objective of this work was to evaluate single head broccoli cultivars production in summer under no-tillage (nt). the experimental design was randomized blocks with a split-plot design and three replicates. the plots were constituted by the cover crops: pearl millet (pennisetum glaucum), corn (zea mays), a mix of corn and black velvet-bean (estilozobium aterrimum), sorghum sudangrass (sorghum bicolor x s. sudanense), besides the conventional tillage (ct) - soil after fallow prepared with plow and disk harrow. cultivars avenger, demoledor, grandisimo, green storm bonanza, legacy and the material hecb-01-06, represented the sub-plots. no differences were found among nt and ct concerning broccoli yield. there were significant differences between cultivars for the evaluated variables. the cultivar avenger presented the highest yield (13.2 t ha-1), average weight (458 g), diameter (15.3 cm) and quality of the curds (index for visual aspect of 4.0). therefore, considering the benefits proportionated by nt, with the maintenance of high productive levels, equivalent at ct, its adoption is recommended.
Suscetibilidade de genótipos de maracujazeiro-azedo à septoriose em casa de vegeta??o
Kudo, Angela Sathiko;Peixoto, José Ricardo;Junqueira, Nilton Tadeu Vilela;Blum, Luiz Eduardo Bassay;
Revista Brasileira de Fruticultura , 2012, DOI: 10.1590/S0100-29452012000100027
Abstract: the objective of this study was to evaluate the reaction of 60 passionfruit (passiflora edulis sims f. flavicarpa degener) genotypes to septoriosis. the experimental design was randomized blocks with four replications and six plants by plot. the inoculation was made by spraying a pathogen suspension (105conidia/ml) on the plants. six evaluations were made weekly, 18 days after inoculation. the disease severity was evaluated following the disease index (1, no symptoms; 2, leaves showing until 10% of lesion area; 3, leaves showing 10 to 33% of lesion area; leaves showing over 35% of lesion area; 5, leaf fall) and the percentage of leaf fall. the genotypes which showed less susceptibility were mar.20.27, joseph and mar.20.36, whereas the genotypes mar.20.59 and mar.20.48 presented the higher index of susceptibility. between the score obtained by the less susceptible genotype (3.4) and the score obtained by the most susceptible genotype (4.5) in the lesion scale, there was a difference of 31.8%, indicating that there is variability among the genotypes for resistance to septoriosis. the difference between the highest (81.6%) and the lowest (49.9%) percentage of leaf fall was of 31.7%.
Caracteriza??o genética de espécies de Passiflora por marcadores moleculares análogos a genes de resistência
Paula, Mariana da Silva;Fonseca, Maria Esther de Noronha;Boiteux, Leonardo Silva;Peixoto, José Ricardo;
Revista Brasileira de Fruticultura , 2010, DOI: 10.1590/S0100-29452010005000021
Abstract: the commercial cultivation of passion fruit can be affected by many diseases, which might induce sever fruit yield losses and significant life cycle reduction of the crop. in some situations disease incidence can make the passion fruit production not economically viable. sources of resistance against several pathogens have been identified in accessions of passiflora germplasm. in the present research we evaluate by using rgas ("resistance gene analogs") markers the genetic diversity of accessions belonging to eight wild species (p. setacea, p. nitida, p. serratodigitata, p. caerulea, p. gibertii, p. odontophyla, p. eduli, and p. coccinea) as well as one interspecific hybrid (p. setacea. x p. coccinea). a remarkable diversity was observed among the rga eletrophoretic profiles of the accessions, allowing the annotation of 96 polymorphic amplicons able to discriminate at least one pair of accessions. the levels of genetic dissimilarity in this group of passiflora accessions (using exclusively this collection of rga markers) ranged from 0.40 to 0.89. the sequence analysis of a subgroup of rga amplicons indicated that they correspond to genomic regions that encompass typical disease resistance gene motifs described in other plant species. our results indicate a quite variable structural repertoire of rga segments in passiflora species with many of them being potentially useful as molecular markers for germplasm fingerprinting systems and also for assisted selection strategies in disease resistance breeding programs in this crop.
Rea??o de genótipos de maracujazeiro-amarelo ao Colletotrichum gloeosporioides
Martins, Irene;Peixoto, José Ricardo;Junqueira, Nilton Vilela Tadeu;Mello, Sueli Corrêa Marques de;
Revista Brasileira de Fruticultura , 2008, DOI: 10.1590/S0100-29452008000300013
Abstract: the present work was carried out in order to evaluate the resistance of passion fruit genotypes to c. gloeosporioides, the agent of anthracnose. c. gloeosporioides was inoculated in the lineages of passion fruit plants at a concentration of 5x106 spores on wounds pre-established by abrasion with a fine steel brush. the first evaluation was carried out 20 days after the inoculation and the others in intervals of seven days, ending in the seventh evaluation 62 days after the inoculation. to evaluate the degree of incidence and severity of anthracnose, a grade scale was established, where 1 = absence of symptoms and 7 = leaf loss. average grades < 2 = resistant (r); > 2 and < 3 = moderately resistant (mr); > 3 and < 4 = susceptible (s) and > = highly susceptible (hs). in general, two genotypes were classified as moderately resistant; eight as susceptible and sixty-two were highly susceptible.
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