Roberta Mn Peil

Crescimento de frutos do meloeiro sob diferentes relações fonte: dreno

An experiment was performed under protected environment from September/2004 to January/2005, to evaluate the effect of plant density and the number of fruits per plant on the growth of melon fruits cultivated in raw rice husk with recirculated nutrient solution. Three planting densities (1,7; 2,4 and 3,0 plants m-2) and two number of fruits/plant (3 and 4) were studied. From the data of dry and fresh matter, 68 days after setting, the biomass production and distribution to the fruits was established. The fruits comprised from 57 to 62% of the total above-ground dry matter production, which demonstrated that they are the strongest sinks for assimilates in melon. At the end of the vegetative period, the melon plant leaf area, when trained vertically and pruned, is relatively low, which in association with a high solar radiation, avoids an excess of mutual shading among the plants, even at higher planting densities. Thus, the increase of planting density does not affect the distribution of dry and fresh matter to the fruits, increasing the absolute plant and fruit biomass production per square meter. The increment of the number of fruits reduced the average dry weight of the fruits, without affecting the production and the distribution of dry matter of the whole plant and fruits. However, the production and the distribution of fresh matter to the fruits take up a different behavior from that of the dry matter, being both benefited with such an increment.

Effect of source: sink ratios and vegetative melon growth

We evaluated the effect of different source:sink ratios determined through variations of planting density and number of fruits per plant during the vegetative growth of melon plants. Two experiments were carried out in a plastic greenhouse in the 2004/2005 spring-summer season. In one experiment, three planting densities (1.7; 2.4 and 3.0 plants m-2) and two different quantities of fruits per plant (3 and 4) were studied. In the other experiment, two treatments were set: pruning all fruits and keeping 3 fruits plant-1, in order to evaluate the effect of the absence of fruits. From the data of dry and fresh matter and leaf area (LA) 68 days after setting, it was determined dry matter production, distribution to the vegetative parts, leaf area index (LAI), specific leaf area (SLA) and dry-matter content of the stems and leaves. The increase of the planting density did not improve the source strength and had no effect on vegetative growth during periods of the year with high solar radiation. At the end of the cropping period, the relatively low melon planting density LA, in association to a high available solar radiation, avoided an excess of mutual shading among plants; this allowed the penetration of solar radiation inside the vegetative canopy, even at higher planting densities. A new fruit competes more with the remaining fruits than with the vegetative organs. The fruits compete indistinctly with the vegetative aboveground parts. In other words, stem and leaf act as an entity. The melon plant adapts to a low demand of sinks accumulating fotoassimilates in vegetative organs.

Efeito da concentração de nutrientes no crescimento, produtividade e qualidade de morangos em hidroponia

Aiming to study the effect of the nutrient solution concentration on plant growth, yield and chemical and phytochemical characteristics of strawberry fruits of cultivar Camarosa in NFT hydroponic system in Pelotas, Rio Grande do Sul state, Brazil, different ionic concentrations (EC) of the solution were evaluated: 0.9, 1.5, 2.1, 2.7dS m-1, in experiment carried out from May 19, 2009 to January 4, 2010; and 0.7, 1.2, 1.7, 2.2, and 2.7 dS m-1, in experiment carried out from June 07, 2010 to January 4, 2011. Fresh and dry matter of leaves, crown, roots and fruits, leaf area, number of fruits and the average fruit weight were evaluated. Fruit samples were analyzed regarding to total soluble solids content, acidity, concentrations of anthocyanins, L-ascorbic acid, total phenolic compounds and antioxidant capacity in the second experiment. The results indicated that EC from 1.2 to 1.5 dS m-1 promoted plant growth and fruit yield. When EC decreased from 1.7 to 1.2 dS m-1, soluble solids, anthocyanin and L-ascorbic acid content decreased by 17, 17 and 15%, respectively; and fruit yield and phenolic compounds concentration were increased by 52 and 22%, respectively. The average fruit weight was reduced with increasing EC in the first experiment and was not affected, as well as the acidity and the antioxidant capacity, in the second experiment. Nutrient solution from 1.2 to 1.5 dS m-1 EC can be indicated to obtain higher yield without major losses in fruit quality in NFT hydroponic system.

Yield of cherry tomatoes depending on the floral cluster and the concentration of nutrients in hydroponics

Yield of cherry tomatoes depending on the floral cluster and the concentration of nutrients in hydroponics The components of yield (number and average weight of fruits per plant) of cherry tomatoes grown in hydroponic system were evaluated, in the summer-autumn 2008 season, noting the influence of the floral cluster position and the nutrients concentration on the solution. Four concentrations of ionic nutrient solution were studied (initial electrical conductivity (CE)): 1.3; 1.8; 2.3 and 2.8 dS m -1 . There was no significant interaction between the factors nutrients concentration of the nutrient solution and position of the floral cluster for all evaluated yield components. Regarding the effect of the position of the floral cluster, significant influence only occurred for the variables fruit setting index and fruit production. The ion concentration of the nutrient solution had significant effect on the following yield variables: fruit mean weight and production of fruits per plant. In terms of fruit mean weight, the CEs of 1.8 and 2.3 dS m -1 were higher than the CE of 2.8 dS m -1 and similar to the CE of 1.3 dS m -1

Efeito da carga de frutos e concentrações salinas no crescimento do meloeiro Cultivado em substrato

O objetivo foi avaliar o efeito do numero de frutos por planta e de concentracoes salinas em solucao nutritiva recirculante, no crescimento do meloeiro cultivado em ambiente protegido e em substrato de casca de arroz crua, durante os meses de fevereiro a maio de 2003. Tres numeros de frutos por planta (2, 3 e 4) e tres concentracoes salinas da solucao nutritiva (1,9; 2,3 e 2,9 dS m-1) foram estudados. A partir dos dados da materia seca (MS) e fresca (MF) e da area foliar, acumuladas aos 62 dias apos o transplante, foi determinada a producao e a distribuicao de biomassa entre as diferentes partes da planta. Os frutos compreenderam de 49 a 55% da MS aerea total produzida pela planta, demonstrando que estes sao os orgaos drenos de assimilados mais potentes. O aumento do numero de frutos reduziu o peso medio dos frutos, sem afetar a producao e a distribuicao de MS total, vegetativa e generativa. Entretanto, aumentou levemente a producao de MF dos frutos e da parte aerea como um todo, favorecendo a distribuicao de MF para os frutos. Portanto, o acumulo de agua nos frutos ocorreu em uma proporcao diferente do acumulo da MS. A menor concentracao salina da solucao nutritiva testada pode ser indicada para o cultivo do meloeiro em substrato de casca de arroz crua durante o outono, pois promove um crescimento da planta similar ao observado nas concentracoes mais altas.

Produtividade biológica de genótipos de tomateiro em sistema hidropônico no outono/inverno

Genotype, incident global solar radiation, temperature, nutrient, water and CO2 availability are some of the factors that in interaction can influence the growth of tomato plants. This study aimed to evaluate seven genotypes of tomato in relation to their biological productivity in hydroponics and fall/winter crop-season, characterized by low solar radiation availability, focusing vegetative and productive aspects, fotoassimilates partitioning and photosynthetic active radiation (PAR) use efficiency in order to determine the most promising for greenhouse cultivation in southern Rio Grande do Sul. The experimental design was randomized blocks with 7 treatments (genotypes) and 3 replications with 6 plants per plot. Among the evaluated genotypes, five are minitomatoes: Cereja Pendente Yubi Feltrin® (determinated growth habit), Cereja Vermelho ISLA®, Minitomate Pera Amarelo TOP SEED®, Grape (no commercial), Flavor Top (no commercial). Also, Santa Cruz Kada Gigante TOP SEED® and Gaucho TOP SEED® tomato varieties were evaluated. Fresh and dry matter productivity (g m-2) of leaves, stems and fruits; leaf area; plant height and compactness; incident global and PAR solar radiations were evaluated. The genotypes Kada Gigante, of Santa Cruz group, and Cereja Pendente Yubi Feltrin®, of determinated growth habit and minitomato group, presented higher fruit yield and PAR use efficiency. So, these genotypes can be considered the most promising for growing in low solar radiation availability crop-season.

Cultivo e uso de variedades crioulas de abóboras ornamentais no Rio Grande do Sul

No Brasil, sao cultivadas variedades crioulas de diversas especies de cucurbitaceas. A maior diversidade genetica de Cucurbita em cultivo parece ser encontrada no Rio Grande do Sul, onde os agricultores praticam e detem o conhecimento popular mediante praticas dinâmicas de guardar e trocar estas sementes, sendo que muitas destas variedades apresentam potencial para uso ornamental. Assim, este trabalho foi desenvolvido com o objetivo de resgatar o conhecimento popular associado ao uso e cultivo de variedades crioulas de aboboras ornamentais no Rio Grande do Sul. Para isso, foram realizadas entrevistas com agricultores doadores de sementes de variedades crioulas do Banco Ativo de Germoplasma (BAG) de Cucurbitaceas da Embrapa Clima Temperado. Nas entrevistas, foi utilizado um questionario semiestruturado, com dados de identificacao do entrevistado (iniciais do nome, idade, sexo, profissao, etnia e local) e questoes norteadoras relativas ao conhecimento sobre aboboras ornamentais (historico de cultivo na familia, procedencia da semente, nome popular atribuido, razoes para manter o cultivo, epoca de plantio e colheita, criterios de selecao dos frutos, formas de utilizacao, local e manejo do cultivo, e formas de retirada e armazenamento das sementes). Foram entrevistados 12 doadores do BAG e, atraves destes, foram localizadas outras nove pessoas que tambem cultivam variedades crioulas de aboboras ornamentais, sendo possivel o incremento de tres novos acessos para o BAG. Foi possivel concluir que ha uma relacao afetiva dos guardioes com suas selecoes e que existe uma grande diversidade de variedades crioulas de aboboras ornamentais mantidas por agricultores familiares do Sul do Rio Grande do Sul.