Produção e partição de biomassa, produtividade e qualidade de mini melancia em hidroponia

• Autor(a) principal: Rodrigues, Silvana
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFPel - Guaiaca
• Texto Completo: http://guaiaca.ufpel.edu.br/handle/123456789/2379
• topic: Citrullus lanatus; Produção de frutos; Cultivo protegido; Massa fresca e seca; Relação fonte: dreno; Citrullus lanatus; Fruit production; Protected cultivation; Fresh and dry matter; Sink: source ratio; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA

The mini watermelons growing in greenhouses can be a more viable alternative crop to be used in rotation or soilless systems under protected cultivation. Greenhouse cultivation and staking require the use and suitability of various other crop management practices, such as increasing plant density and fruit thinning. Two experiments were performed at the Universidade Federal de Pelotas, RS from November 2010 to January 2011, in order to study plant growth (dry matter production and partitioning), fruit yield and quality of mini watermelon Rapid Fire under greenhouse and NFT hydroponic system conditions. The first experiment aimed to study different plant densities (1.8, 2.4, 2.9, 3.4 and 3.9 plants m-2), setting four fruits per plant. The second experiment was conducted to verify the effect of sink demand (number of fruits per plant) in five levels (01, 02, 03, 04 and 05 fruits per plant). Fresh and dry matter of leaves, stems, roots and fruits, leaf area, average fruit weight, soluble solids content and pulp colour were evaluated. Regarding the results obtained in the first experiment, it was observed that increasing plant density from 1.8 to 3.9 plants m-2 reduced linearly growth of all organs and fruit yield per plant (from 9.58 to 7.47 kg) and presented no effect on fruit sugar content and pulp colour. However, from a marketable point of view, it neither caused losses in the average fruit weight (ranging from 2.39 to 1.86 kg) nor altered the plant dry matter partitioning. But, it increased linearly crop and fruit dry matter production as well as fruit yield obtained per square meter (from 17.23 to 29.11 kg m-2).Thus, we can recommend the density of 3.9 plants m-2 for the stanking mini watermelon Rapid Fire in hydroponic cultivation. The results obtained in the second experiment indicate that increasing fruit load caused a strong competition by fotoasimilates among different plant organs and reduced leaf expansion and fruit as well as other plant organs dry matter production. But, it had no effect on dry matter partitioning. Thus, one fruit per plant can be considered as the saturation fruit load related to the fraction partitioned into fruits. A linear reduction of the average fruit fresh weight from 3.42 kg to 1.77 and 1.26 kg was observed when the number of fruit increased from one to 4 and 5 fruits, respectively. Also, fruit soluble solids content was reduced, without any effect on pulp colour. The water accumulation into the fruits occurred differently from the dry matter accumulation. As a consequence, fruit yield increased linearly from 3.42 kg plant-1, at one fruit, until 7.09 kg plant-1, at 4 fruits per plant. The obtained results allow us to recomend a fruit load of two fruits per plant when the goal is to achieve more quality markets and three fruits per plant, when the goal is to increase fruit production without major losses in fruit quality of mini watermelon Rapid Fire in hydroponic cultivation.