Tatiana S. Duarte

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 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.

Preparados homeopáticos en el crecimiento y en la producción de repollo cultivado en sistema orgânico

El repollo es consumido preferencialmente in natura y en muchos casos es producido de manera convencional, dejando trazas de residuos quimicos, lo cual puede generar afecciones directas sobre la salud del consumidor y del agricultor. El objetivo del trabajo fue evaluar la influencia de preparados homeopaticos en altas diluciones en el crecimiento de plantulas y en la produccion de repollo, en sistema organico. El trabajo fue compuesto por cinco experimentos para estudiar nueve tratamientos con cuatro repeticiones siendo la conduccion de tres experimentos en invernadero, utilizando el diseno experimental de bloques completos al azar, y de dos experimentos en el campo utilizando el diseno experimental de bloques al azar. Los tratamientos estudiados fueron los preparados de Arnica montana,Silicea terra, Carbo vegetabilisy Sulphur en la 6CH y 30CH (orden de dilucion centesimal hahnemanniana); y agua como testigo. Sulphur6CH aumento en dos de los tres experimentos la altura y la longitud de raiz en relacion al testigo, en plantulas de repollo. Silicea terra 30CH y Sulphur6CH aumentaron la produccion y la materia seca de cabezas de repollo cultivadas en campo, asi como, Arnica montana 6CH y 30CH tambien incrementaron la materia seca de cabezas. Se concluyo que Sulphur6CH se destaco como promisorio para mejorar la calidad de las plantulas de repollo, asi como en la produccion y materia seca de cabezas de repollo en condiciones de campo siendo estas ultimas caracteristicas tambien mejoradas por Silicea terra30CH.

Posição dos frutos e seu efeito na repartição da matéria seca da planta do tomateiro

Tomato plants were grown in Spring and Fall in a non-heated greenhouse in order to investigate the effect of fruit position on dry matter distribution between vegetative organs and fruits. Treatments consisted of plants with one shoot (control) or two shoots per plant, with fruits located in both stems or only in the main stem. In each experiment, the same number of trusses was kept in all plants, by truss removal on the double-shoot plants. Thus, truss number per plant was eight in Spring and ten in Fall, while number of leaves per plant was respectively 27 and 37 in control plants and 52 and 65, on average, on the double-shoot plants. In Spring, mean fruit dry matter was 155g on double-shoot plants and 95g on control plants. In Fall, mean fruit dry matter accumulation was 99g in double-shoot and 78g in single-shoot plants and differences were not significant. In both seasons, no significant differences were recorded between double-shoot treatments, regardless of the position of fruits on the stem. In Fall, the fraction of total dry matter allocated to fruits was 0.40 in control and 0.24, on average, on the double-shoot plants, suggesting sink strength of fruits was affected by low temperatures. It was concluded that fruit position do not affect dry matter distribution and results support the hypothesis of one common pool of assimilates circulating freely in the tomato plant.

Progresso temporal da cercosporiose da beterraba em diferentes genótipos e épocas de semeadura na primavera

Beet cultivation has intensified due to in natura consumption and industrial processing of canned food. In the region of Alto Vale do Itajai, Santa Catarina State, Brazil, a large part of beet production comes from small farmers, who grow it after the onion crop, sowing it during the spring/summer. However, in this period of the year, Cercospora leaf spot has been noted to compromise the production. The aim of this study was to evaluate the progression of this disease in the following genotypes: All Green, Stays Green, Early Wonder, Cabernet, Boro, Modana and Itapua, as well as to evaluate its severity in two sowing periods during the spring. The two assays were carried out at Epagri Experimental Station in Ituporanga, Santa Catarina State, and established at 30-day interval between sowing periods. Experimental design was in randomized blocks with four replicates. To evaluate the disease severity, a diagrammatic scale was used for ten plants at random, which were previously demarcated. Data on severity underwent mixed model analysis, yielding area under the disease progress curve (AUDPC), infection rate and final disease severity. There were no differences in the disease progression between the evaluated genotypes for both spring sowing periods under the conditions of Alto Vale do Itajai, Santa Satarina State, Brazil.

Reaction of beet genotypes to the Beet Leaf Spot in the upper Valley of Itajaí, Santa Catarina state, Brazil

In the region of the Upper Valley of Itajai, Santa Catarina state, Brazil, family farmers cultivate beet (Beta vulgaris) along with other products such as, onion. However, some diseases, including the Beet Leaf Spot (Cercospora beticola), have compromised the success of the beet crop due to severe leaf incidence. The objective of this study was to evaluate the reaction to the Beet Leaf Spot, under local conditions, in the spring-summer season, of the beet cultivars most frequently used by farmers in the region, namely All Green, Stays Green, Early Wonder, Cabernet, Boro, Modana and Itapua. Two experiments, with a 30-day interval between sowings were carried out in EPAGRI, Experimental Station of Ituporanga. The experimental design was of randomized complete blocks with four replications and 2,25 m² plots. Disease severity was assessed weekly, using a diagrammatic rating scale, in ten plants taken at random and previously labelled. Disease severity data were used to calculate the area under the disease progress curve (AUDPC) for each cultivar. Same plants were used to estimate yield. AUDPC and yield data were submitted to analysis of variance (F-test, 5% probability), and means were studied by the Scott-Knott test (5% probability). There were no significant differences between cultivars, nor for reaction to the disease, neither for yield, in any of the two sowing dates. In both experiments, cultivar All Green scored the highest severity value in the last assessments, 18.46 and 19.84% respectively in the first and second sowing dates, while hybrid Boro (17.79%) in the first experiment, and Stays Green and Cabernet (18.04%) in the second, recorded the lowest values. We concluded that all cultivars were susceptible to the Beet Leaf Spot in spring-summer conditions in the Upper Valley of Itajai.