Cultivos de pimentões sob telas fotosseletivas

• Autor(a) principal: Rosa, Juliano Queiroz Santana
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000dts0
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/11468
• topic: Plasticultura; Radiação fotossinteticamente ativa; Substrato; Plasticulture; Photosynthetically active radiation; Growing media; CIENCIAS AGRARIAS::AGRONOMIA

Sweet pepper is among the ten most important vegetable crops in Brazil, the production concentrating in the Southeast and Central-West regions, where Goiás State is the largest producer. Sweet pepper is traditionally cultivates at open field, but protected cultivation allows for increasing productivity as well as out of season production. Among the technologies available for shading are the photoselective screens, which attenuate the solar radiation by way of transmitting better quality incident solar radiation spectra for the photosynthesis process. Limited research has been developed on this subject in the Goiás State. A study was proposed, carried out at Goiânia, Goiás State, Brazil (16o35’73”S, 49o16’54”W, 716m), under two objectives: 1) Evaluation of sweet peppers seedling production under red and blue photoselective screens, a thermo-reflective screen, and a tunnel plastic greenhouse; 2) Evaluation of the vegetative development and yield of two sweet pepper cultivars (yellow and red), grown under blue and red photoselective screenhouses, and at open field. In the first experiment sowing was made in 128-cell trays filled with commercial growing media, in completely randomized design, with 16 plots per treatment and 12 seedlings per plot. All data variance were analyzed and compared by the Scott-Knott test at 5% significance. Solar global radiation (GR), photosynthetically active radiation (PAR), temperature, and air relative humidity were continuously registered. Data show that in May and June temperature has greater influence in seedling development than GR and PAR. The conclusion of the study is that better quality seedlings are obtained in greenhouses covered with low density polyethylene as compared to those grown under 40% shading blue or red photoselective or thermoreflective screens. In the second experiment the Eppo (yellow) and Margarita (red) hybrids were grown in 16m x 12m x 2,2m 40% shading screenhouses. The control treatment was open sky beds. For each cultivar 140 seedlings were planted per environment, making up six independent populations. Stalk diameter and length and leaves number, area, and mass were measured. At 120 days from transplanting fruit number, mass, length, and diameter were measured, as well as the number of fruits lost by sun scald. Data show that photoselective red and blue screens increased stalk growth and decreased the number of leaves and fruits. No statistical differences were observed for leaf area, showing that there is compensation between leaf number and area. Total fruit production per plant decreased from open sky to red screen to blue screen. However, fruit losses by sun scald reached 35% at open sky and 6% under screens. Commercial fruit production per plant was higher under red screen, followed by open sky and blue screen. The conclusion is that, for the red and yellow sweetpeppers and environments studied, 40% shading red screen results in better plant growth and a small (4%) increase in commercial fruit production as compared to blue screen and open sky.