Protected Environment Conditions Research Articles

Effect of Different Irrigation Levels on Yield Attributes of Black Pepper (<em>Piper nigrum</em> L.)

The growth of black pepper cultivations in Sri Lanka has been restricted to the Wet Zone of Sri Lanka due to lack of sufficient soil water in the Dry Zone as well as in certain parts of the Intermediate Zone. Therefore, identification of optimum irrigation level to get a higher yield of black pepper is vital as such information is limited. A pot experiment was conducted under protected environmental conditions to determine the effect of different irrigation levels on yield attributes of black pepper. Weekly irrigation was administered to three-year-old MB-12 vines at three different levels (8, 4, and 2 L vine-1 week-1; 8 L vine-1 week-1 represents near field capacity) with 3 replicates each. The experiment design was Completely Randomized Design (CRD). Black pepper vines provided with an irrigation level of 8 L vine-1 week-1, recorded significantly higher (P<0.05) mean values for yield attributes such as dry weight of berries of 10 spikes (40.5 g), spike length (11.76 cm), number of spikes per vine (81), number of berries per spike (87.4), and spike filling percentage (88.9%). In conclusion, irrigation level near field capacity (8 L vine-1) is preferable to get a greater yield from black pepper. Further studies are suggested at the field level before making a solid recommendation.

NITROGEN IMPROVES BIOMASS PRODUCTION AND CHLOROPHYLL SYNTHESIS IN BASIL PLANTS GROWN UNDER SALT STRESS

Basil (Ocimum basilicum L.), a medicinal and aromatic plant extensively cultivated in the Northeast region of Brazil, encounters growth challenges attributed to the salinity of irrigation water and soil. Nitrogen (N) is a crucial macronutrient employed to mitigate salt stress in plants. Therefore, this study aimed to evaluate the production of phytomass and chlorophyll synthesis in purple basil plants grown under salinity stress and nitrogen fertilization. The experiment was conducted in 2021 under protected environmental conditions at the Center for Agricultural Sciences, Universidade Federal Paraíba, Areia-PB, Brazil. Five levels of salt stress (0.0, 0.80, 2.75, 4.70, and 5.50 dS m-1) and five doses of N (0.00, 58.58, 200.00, 341.42, and 400.00 mg L-1) applied via foliar were studied. The results revealed that foliar fertilization with N increases plant tolerance to salt stress, promoting root fresh and dry mass accumulation at 294.96 and 205.36 mg L-1 and under ECw of 1.14 and 0.5 dS m-1, respectively. Applying 217.39 and 231.30 mg L-1 of N improves the production of stem dry biomass and the shoot/root ratio of basil plants subjected to salinity of 0.5 dS m-1. The electrical conductivity of irrigation water above 0.8 dS m-1 adversely affects biomass production. The salinity at 3.8 to 4.0 dS m-1 stimulated chlorophyll synthesis in purple basil plants. However, the foliar application of N proves to be a strategic approach to counteract these effects, resulting in increased total dry mass production and chlorophyll contents.

Diâmetro do caule para enxertia do tomate italiano

ABSTRACT The adoption of grafting in vegetable production is an innovative technique that presents challenges to be overcome, which one of the main ones is the need to determine the appropriate diameter of the plant at the time of grafting. Therefore, the objective of this work was to evaluate the development of seedlings and production of tomato plants, grafted with different stem diameters, under protected environmental conditions. The experiment was divided into two phases, seedling development and field production. The experimental design was completely randomized with five treatments, composed of the following seedlings stem diameters at the time of grafting: 1.8; 2.0; 2.2; 2.5 and 2.8 mm. Morphophysiological and productive characteristics of the grafted plants were evaluated. The results demonstrated that Italian tomato seedlings, grafted with 2.2 mm stem diameter, showed better development. However, the production rates were similar for the different stem diameters (1.8 to 2.8 mm) adopted at the grafting moment. Estimated yields of around 200 t/ha, much higher than the national average, demonstrate the success of the grafting technique in Italian tomatoes, under protected environmental conditions.

Can saline irrigation improve the quality of tomato fruits?

AbstractThis study aimed to investigate the effect of irrigation with saline water on fruit quality, yield, and plant nutrition of tomato (Lycopersicon esculentum Mill.) cultivars. Tomato cultivation was carried out under protected environment conditions in a double row system with drip irrigation performed according to the demand of the plants. Commercial fruit weight, commercial fruit number, fruit yield, absorption of Ca, N, P, S, K, and Mg were all affected by saline irrigation. The leaf Na concentration and the concentration of total phenolic compounds, total titratable acids, total soluble solids, vitamin C, carotenoids, and flavonoids in the fruits were favored from the increase in irrigation salinity. The Na+ causes a deficiency of Ca, which impairs seed formation in tomato fruits, as Ca is a structural element in the formation of the pollen grain. The Onix genotype had the highest yield, weight, and number of commercial fruits under control and moderate salt stress conditions. Saline water impaired nutrient absorption and improved tomato fruit quality. Under salt stress, tomato plants were able to absorb and translocate large amounts of Na+ to the shoot and even improved the organoleptic quality of fruits, increasing the content of carotenoids, flavonoids, vitamin C, total phenolic compounds, total soluble solids, and total titratable acids of tomato fruits. The clustering analysis was able to show the highest genetic dissimilarity between the group composed of Shanty, Maestrina, and Ipa 6 and the group with Sheena, Totalle, and Pizzadoro under salt stress conditions; also, it evidenced the greater stability of these genotypes.

Assessment of Yield and Nitrate Content of Wall Rocket Grown under Diffuse-Light- or Clear-Plastic Films and Subjected to Different Nitrogen Fertilization Levels and Biostimulant Application

The quantity and quality of wall rocket (Diplotaxis tenuifolia L.) production are strongly influenced by the cultivation system, in particular the protected environment conditions and nitrogen fertilization. In the present research, we tested two greenhouse cover films (Film1: diffuse light; Film2: clear), to verify the effects on yield and nitrate content (a detrimental factor of quality) of rocket leaves, fertilized with optimal (N2) or sub-optimal nitrogen dose (N1), or unfertilized (N0). In addition, we combined the N fertilization with a biostimulant application, declared by the manufacturer as able to reduce nitrate content. Film1 provided a 36% yield increase over Film2 and allowed an increasing production until the V harvest, opposite to what was recorded under Film2, where the yield increased only until the III harvest. Additionally, biostimulant application boosted the yield (+40%), as well as nitrogen fertilization. Both factors had the best performance under Film1, where N1 yield was even equal to N2-Film2. The nitrate content showed a seasonal trend (lower values in spring harvests) and it was boosted by nitrogen (1096, 3696, and 4963 mg/kg fresh weight, for N0, N1, and N2, respectively) and biostimulant application (3924 vs. 2580 mg/kg fresh weight). Therefore, the use of diffuse-light film seems useful to obtain higher yield with a halved N dose as well as in combination with biostimulant application, but the latter did not confirm the capacity to contain nitrate, at least for this crop and in this cultivation system.

Fisiologia e fitomassa de porta-enxerto de cajueiro sob águas salinizadas e adubação orgânica

O uso de águas salinas na agricultura tornou-se uma alternativa em diversas regiões do mundo, contudo é necessário o desenvolvimento de técnicas para viabilizar o uso dessas águas na agricultura. Diante do exposto, objetivou-se avaliar o efeito da salinidade da água de irrigação sob as respostas fisiológicas e produção de fitomassa de porta-enxerto de cajueiro anão precoce CCP 06 associado a doses crescentes de matéria orgânica, em experimento conduzido em condições de ambiente protegido do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande (CCTA/UFCG), Campus de Pombal (PB). Utilizou-se o delineamento experimental de blocos casualizados, em esquema fatorial 5 x 4, com 3 repetições e duas plantas por parcela, sendo os tratamentos compostos de cinco níveis de condutividade elétrica da água (0,3; 1,0; 1,7; 2,4; e 3,1 dS m-1) e quatro doses de matéria orgânica (2,5; 3,5; 4,5; e 5,5% em base do volume de solo). A salinidade da água de irrigação de até 0,90 dS m-1 proporciona perdas aceitáveis de 10% na transpiração, condutância estomática e a fotossíntese líquida dos porta-enxerto de cajueiro CCP 06. A dose de MO de 2,5% proporcionou maior produção de massa seca do caule sobre o de porta-enxerto de cajueiro CCP 06 durante o período de execução do trabalho. O aumento da salinidade na água de irrigação causa os efeitos deletérios sobre a massa seca de folha, caule e raiz em ambos os períodos estudados.

PRODUCTION CHARACTERISTICS OF SESAME GENOTYPES UNDER DIFFERENT STRATEGIES OF SALINE WATER APPLICATION

ABSTRACT In semiarid areas, the scarcity of water with low salt concentration associated with irregular precipitation becomes a limiting factor to ensure agricultural production. In this context, the objective of this study was to evaluate the growth and production of sesame genotypes under different strategies of use of saline water. The experiment was conducted under protected environment conditions, using a randomized block design in a 6 x 2 factorial scheme, and the treatments consisted of six strategies for the use of saline water in the different stages of plant development (SE = irrigation with low-salinity water throughout the cultivation cycle; VE, FL, FR, VE/FL and VE/FR - respectively, irrigation with high-salinity water at the vegetative stage, flowering, fruiting, vegetative/flowering and vegetative/fruiting) and two sesame genotypes (BRS Seda and BRS Anahí), with 4 replicates. Irrigation with high-salinity water (ECw = 2.7 dS m-1) during the vegetative, flowering and fruiting stages did not compromise sesame production. There were reductions in sesame growth when irrigation with high-salinity water was continuously applied at the vegetative/flowering stages and in sesame production when it was applied during the vegetative/flowering and vegetative/fruiting stages. The greater growth of BRS Seda sesame plants resulted in an increase in the total number of fruits and in the total seed weight.

Effect of Nitrogen Fertilization on the Growth and Quality of Tamarind Seedlings Irrigated with Saline Water

Aims: The objective of this work was to evaluate the effect of nitrogen fertilization on the production of Tamarindus indica L. seedlings irrigated with saline water.
 Study Design: A randomized complete block design was used in a 4 x 4 factorial scheme, whose factors were the electrical conductivity levels of the irrigation water.
 Place and Duration of Study: The work was conducted under protected environment conditions (greenhouse) at the Federal University of Campina Grande, Center for Agro-Food Sciences and Technology, Campus of Pombal-PB, Brazil, in the period from January and March 2017.
 Methodology: Effects of doses of 0, 100, 200 and 300 mg of nitrogen (N) dm-3 and electrical conductivity levels of the irrigation water (ECw) (0.3, 2.1, 3.7 and 5.2 dS m-1) on growth of Tamarindus indica L. have been studied.
 Results: The growth of the seedlings was reduced by the increase of the electrical conductivity of the irrigation water, however, irrigation with ECw water of 2.15 dS m-1, promotes acceptable reductions of 10% in the morphology of the tamarind tree.
 Conclusion: The use of nitrogen fertilization with urea did not attenuate the deleterious effects of irrigation water salinity or promoted improvements of the quality of the tamarind seedlings.

Growth and production components of West Indian cherry cultivated with saline waters and potassium fertilization

ABSTRACT Due to water limitations in terms of both quantity and quality in the semi-arid region of northeastern Brazil, the use of waters with high concentrations of salts become necessary in irrigated agriculture. Thus, this study aimed to evaluate the growth and production of grafted West Indian cherry under saline water irrigation and potassium fertilization. The experiment was carried out in drainage lysimeters under protected environment conditions, using a Regolithic Neosol with sandy loam texture. Treatments resulted from the combination of two levels of electrical conductivity - ECw (0.8 and 3.8 dS m-1) of irrigation water and four doses of potassium (50, 75, 100 and 125% of the recommendation of Musser), arranged in a randomized block design, with three replicates. Irrigation water salinity of 3.8 dS m-1 markedly inhibited the growth in stem diameter and mean fruit weight of West Indian cherry. Potassium fertilization mitigated the deleterious effects of salt stress on the relative growth in stem diameter of the rootstock, total number of fruits and total fresh mass of fruits of West Indian cherry, with highest values in plants irrigated with water of lowest level of salinity associated with the highest dose of K2O.

Pulse drip irrigation and fertigation water depths in the water relations of coriander

ABSTRACT This study was installed to evaluate the effect of pulse drip irrigation under different water depth levels (fertigation) in the main water relations of coriander crop (Coriandrum sativum). The experiment was installed under protected environment conditions, at UFRPE, Recife, Brazil. The experimental design was randomized blocks in a 2x5 factorial scheme, with three replications. Treatments consisted of two application types (continuous and pulsed irrigation), and five water depths with replacement of 40, 60, 80, 100 and 120% of crop evapotranspiration (ETc). Water demand was estimated through water balance using a drainage lysimetry. Six irrigation pulses were defined with a 60-minute-rest interval between two successive applications. Plants irrigated by pulses showed higher water productivity values (fresh and dry mass), higher water content (shoot and root), higher shoot mass production index and lower root mass production index and root-shoot ratio. The reduction of applied fertigation water depths increased plant water stress index. The irrigation pulses used ensured water content able to maintain the crop’s marketable quality. Pulse application in irrigation system increased shoot mass production index and reduced root mass production index.

Can an earth plaster be efficient when applied on different masonries?

Earth mortars are known for being ecological but also reversible, contributing to comfort and aesthetic. Nevertheless, compatibility with different masonries is scarcely assessed. A commercial unstabilised ready-mixed earth mortar was produced with an ilitic earth with addition of sand and oat straw fibres. It was used to plaster different experimental masonry walls, at protected outdoors environmental conditions. The plasters applied on the masonries were visually monitored and characterized in situ by non-destructive techniques and in laboratory by bulk density and microstructure. The same mortar used for the plasters was characterized in laboratory in fresh state and, after drying, on prismatic specimens and specimens composed by a mortar layer applied on hollow bricks. Some variation of results occurs when the same unstabilised ready-mixed earth mortar is used to plaster different masonries, what may be related to the water absorption of the masonry materials. However, after six months the earth plaster presented durability on the different masonries when protected from rain. It proves that this ecological mortar is technically efficient to plaster different types of masonry, historical or contemporary.

Crescimento de algodoeiro colorido cv. BRS Topázio em solos com distintas salinidades e adubação orgânica

Naturally colored fiber cotton has been attracting interest from producers and consumers in Brazil and around the world, with a view to being a growing market with great socioeconomic potential for labor, employment and a source of raw material for industry textile. Regarding the above, the objective was to evaluate the growth and phytomass production of cotton cv. BRS Topaz cultivated in soils of different PSTS and doses of bovine manure under protected environment conditions in CCTA/UFCG. The experimental design was a randomized complete block design in a 5 x 4 factorial scheme with three replicates, and the treatments were composed of five percent exchangeable sodium (PST) (8.84, 12.55, 18.80, 28.80 and 38.80%) associated to the goat manure factor, being 0, 5, 10 and 15% of the volume of the pot. The PST from 24% affects the leaf area and the fresh and dry leaf has its production reduced from the PST of 38.14 and 32.60% respectively.Fertilization with bovine manure promotes an increase in growth and phytomass production of cotton cv. BRS Topaz. There was no interaction between the percentage of exchangeable sodium and doses of bovine manure on the variables under study.

Cherry tomato production on different organic substrates under protected environment conditions

The cherry tomato (Lycopersicon esculentum var. cerasiforme) is gaining importance as an alternative crop, mainly for small farms that use family hand labor and organic management. In this study, we investigated the effects of organic substrate combinations of cattle manure (M), vermicompost (VC), and vermiculite (V) on the yield and quality of cherry tomato fruits. Cherry tomato plants of the cultivar Carolina were grown under greenhouse conditions in 5-L pots. The five investigated substrate combinations were as follows: (T1) 80% M + 10% VC + 10% V; (T2) 70% M + 15% VC + 15% V; (T3) 60% M + 20% VC + 20% V; (T4) 50% M + 25% VC + 25% V; and (T5) 40% M + 30% VC + 30% V. Plant growth, tomato yield, and physicochemical properties of the fruits were measured. The results showed that combinations of 50% M + 25% VC + 25% V and 40% M + 30% VC + 30% V led to the best growth and adaptation of cherry tomato plants, resulting in larger and more rounded fruits. The substrate containing 40% M + 30% VC + 30% V resulted in higher numbers of fruits per plant. Different substrate combinations did not affect the chemical quality of the fruit. Therefore, our study has provided valuable information on the use of organic substrates in cherry tomato production under protected environment conditions. Based on our results, the different combinations of cattle manure, vermicompost, and vermiculite used in this study represent excellent options for reducing production costs and re-using organic byproducts.

Dissipation of spiromesifen and spiromesifen-enol on tomato fruit, tomato leaf, and soil under field and controlled environmental conditions.

Dissipation of spiromesifen and its metabolite, spiromesifen-enol, on tomato fruit, tomato leaf, and soil was studied in the open field and controlled environmental conditions. Sample preparation was carried out by QuEChERS method and analysis using LC-MS/MS. Method validation for analysis of the compounds was carried out as per "single laboratory method validation guidelines." Method validation studies gave satisfactory recoveries for spiromesifen and spiromesifen-enol (71.59-105.3%) with relative standard deviation (RSD) <20%. LOD and LOQ of the method were 0.0015μgmL-1 and 0.005mgkg-1, respectively. Spiromesifen residues on tomato fruits were 0.855 and 1.545mgkg-1 in open field and 0.976 and 1.670mgkg-1 under polyhouse condition, from treatments at the standard and double doses of 125 and 250ga.i.ha-1, respectively. On tomato leaves, the residues were 5.64 and 8.226mgkg-1 in open field and 6.874 and 10.187mgkg-1 in the polyhouse. In soil, the residues were 0.532 and 1.032mgkg-1 and 0.486 and 0.925mgkg-1 under open field and polyhouse conditions, respectively. The half-life of degradation of spiromesifen on tomato fruit was 6-6.5days in the open field and 8.1-9.3days in the polyhouse. On tomato leaves, it was 7-7.6 and 17.6-18.4days and in soil 5.6-7.4 and 8.4-9.5days, respectively. Metabolite, spiromesifen-enol, was not detected in any of the sample throughout the study period. Photodegradation could be the major route for dissipation of spiromesifen in the tomato leaves, whereas in the fruits, it may be the combination of photodegradation and dilution due to fruit growth. The results of the study can be utilized for application of spiromesifen in plant protection of tomato crop under protected environmental conditions.

Effect of grafting on the control of gummy stem blight in muskmelons

Gummy stem blight, caused by Didymella bryoniae, is the most important fungal diseases of muskmelons cultivated in protected environments in Brazil. Fungicides are used to control this disease, and little is known about the effectiveness of alternative control methods. The aim of this study was to evaluate the effect of grafting on the control of gummy stem blight in four muskmelon hybrids. The hybrids Bonus II, Sunrise, Louis and Prince hakusho were grafted onto the squash hybrid Shelper, which is immune to D. bryoniae. Two experiments were conducted, one in greenhouse with artificial inoculation of the pathogen and the other in protected environment using crop residues and soil infected with the pathogen. Under greenhouse conditions, mycelial discs of the pathogen were inoculated onto the hypocotyl or at the union graft/rootstock region of the grafted plants and onto ungrafted plants of each hybrid. By growing these four melon hybrids in a protected environment, the effect of grafting on the control of gummy stem blight could be studied. When these melons were grown in the greenhouse or in a protected environment, grafting significantly reduced the growth of gummy stem blight in all four melon hybrids. For grafted hybrid plants inoculated at the hypocotyl, the disease severity decreased by 34.1%, 33.8%, 51.1% and 48.0% for Sunrise, Bonus II, Louis and Prince hakusho, respectively, compared to ungrafted plants. For grafted plants inoculated at the union graft/rootstock region, the disease severity decreased by 54.3%, 57.3%, 54.1% and 44.6%, respectively. For melons grown in protected environments, grafting reduced the severity of gummy stem blight in the four melon hybrids by 34.3%, 34.8%, 45.8% and 49.6%, respectively. Thus, grafting onto immune rootstocks significantly reduced the severity of D. bryoniae in the four muskmelon hybrids grown under greenhouse and protected environment conditions.

Acúmulo de carboidratos no desenvolvimento de tomateiro tratado com produtos químicos

This work had the purpose to study the physiological effects of pyraclostrobin, boscalid, plant growth regulators and plant extract on the accumulation of carbohydrates during the development of tomato plants ( Solanum lycopersicum L.), hybrid Giuliana, in protected environment conditions. The treatments were: T1- control; T2- pyraclostrobin 0.2 g L-1; T3- boscalid 0.075 g L-1, T4- pyraclostrobin 0.2 g L-1 + boscalid 0.075 g L-1, T5- IBA + GA3 + kinetin 375 mg L-1, T6- GA4+7 + benzylaminopurine 100 mg L-1 and T7- plant extract 100 mg L-1. The carbohydrate accumulation curve was accomplished with 5 samples, at 20-day intervals between evaluations, the 1st evaluation being carried out at 30 days after transplantation, on the day of the first treatment application. At each sampling the plants were separated in stem, leaves and fruits, of which the contents of total soluble sugars, reducing sugars and saccharose were evaluated. The effects of the treatments on chlorophyll content and gas exchanges were also evaluated. The experimental design was completely randomized, with 4 repetitions and 6 destructive evaluations during the development, with 1 plant per experimental unit for each sampling. The pyraclostrobin and boscalid applied in isolation and/or combined favor the increase of carbohydrates in leaves, stems and fruits of tomato hybrid Giuliana.

Suppressiveness of white vinegar and steam-exploded liquid waste against the causal agents of Pleurotus eryngii yellowing

During a survey of mushroom-beds in Apulia and Basilicata (southern Italy), several bacterial strains belonging to the fluorescent pseudomonads group have been isolated from the basidiomata of Pleurotus eryngii on account of symptoms of yellowing. On the basis of LOPAT tests, 95% of the recovered bacteria were identified as Pseudomonas fluorescens. In particular, 83% of them were recognized as P. ‘reactans’ because they were able to produce a white line against P. tolaasii strain NCPPB-2192. In preliminary in vitro experiments, commercial white vinegar (WV) and steam-exploded liquid waste (SELW) solution derived from Miscanthus sinensis biomass proved to have an effective antibacterial activity against P. ‘reactans’, P. tolaasii and fluorescent pseudomonads isolates used as targets. In particular, WV induced a bacterial inhibition reaching 89% and 65% on tested P. ‘reactans’ and fluorescent pseudomonads strains, respectively. Undiluted M. sinensis SELW reached an inhibition of 20–50% against tested strains. No antibacterial effects were associated with Arundo donax and wheat straw SELWs. The bacterial suppressiveness of WV and M. sinensis SELW was subsequently studied in vivo throughout two “cardoncello” mushroom cropping cycles performed under protected environmental mushroom-bed conditions using the P. eryngii commercial strain “3065” and six Pseudomonas strains (3 belonging to P. ‘reactans’, 2 to P. fluorescens and 1 to P. tolaasii). Cell suspensions of the single Pseudomonas strains were sprayed as inoculum onto covering soil as soon as “cardoncello” primordia appeared. Specifically, WV with 6‰ acidity and M. sinensis SELW, were effective as antibacterial substances. In particular WV led to a 4.5–6.1, 2.2–4.3 and 3.5–4.4-fold increase in sporophore yield when sprayed: a) on the surface of substrates colonized by “cardoncello” mycelium right before casing soil distribution, b) right after casing soil distribution and c) on casing soil and basidioma surface at 3–4-day intervals. M. sinensis SELW increased the sporophore yield 6.1-fold when sprayed right after casing soil distribution.

Adaptive and Foraging Behavior of Two Stingless Bee Species in Greenhouse Mini Watermelon Pollination

The growth of protected cultivation in the world agriculture has driven crops traditionally cultivated in open field to enclosures, which, in turn, prevent the access of pollinators to flowers. Therefore, it became necessary to identify suitable pollinators for confined environments. Stingless bees have been pointed out in Brazil as the ideal pollinators for crop pollination under these conditions. Aiming to evaluate the viability of using two stingless bee species in a protected environment conditions, colonies of Melipona subnitida (D.) and Scaptotrigona sp. nov. were introduced in a greenhouse during the flowering of seeded (diploid) and seedless (triploid) mini watermelon ( Citrullus lanatus T.) varieties. The feasibility of using these bee species was evaluated based on the adaptive and foraging behavior under the protected environment conditions. Melipona subnitida did not show any interest to the crop under the experimental conditions, stopped foraging trips and egg laying in a diapause-like stage. On the other hand, Scaptotrigona sp. nov. foragers were active and collected floral resources since the second day after their introduction. Moreover, the foragers of Scaptotrigona sp. nov. showed an essential behavior for mini watermelon pollination, because they visited staminates and pistillates flowers from both seeded and seedless genotypes for nectar collection. We concluded that M. subnitida did not adapt to the greenhouse mini watermelon cultivation under the experimental conditions and should not be used for pollination purposes in such a situation. Contrasting, Scaptotrigona sp. nov. adapted well to the greenhouse and should be preferred for greenhouse mini watermelon pollination.

Crescimento de cultivares de girassol ornamental influenciado por doses de silício no solo

Poucos são os trabalhos experimentais através dos quais se analisou o crescimento do girassol ornamental em condições de ambiente protegido. Objetivou-se então, no presente trabalho, avaliar doses de silicato de cálcio e magnésio no crescimento de duas cultivares de girassol ornamental. O experimento foi conduzido em casa de vegetação no período de setembro a dezembro de 2010. Os tratamentos foram dispostos no delineamento inteiramente casualizado, com três repetições, em um arranjo fatorial 5 x 2 referente às doses de 0; 2; 4; 6 e 8 g de Si por vaso e as cultivares de girassol ornamental Jardim Amarelo Alto e Sol Vermelho. As unidades experimentais foram constituídas de vasos plásticos com capacidade de 10 L, com 5,33 L de solo. Todas as unidades experimentais receberam adubação com N:P2O5:K2O nas doses de 60-80-80 kg ha-1. As doses de silício aumentaram significativamente o diâmetro externo do capítulo e a abertura total do botão floral (dias) de plantas de girassol. A cultivar Sol Vermelho apresentou melhor resposta à aplicação de silício em relação ao Jardim Amarelo Alto.

Avaliação de métodos de estimativa da evapotranspiração horária para alface cultivada em sistema hidropônico em ambiente protegido

O objetivo deste trabalho foi avaliar a precisão e a exatidão de métodos de estimativa de valores horários de evapotranspiração (ETc) para alface cultivada em sistema hidropônico sob ambiente protegido. Para a determinação dos parâmetros pertinentes aos diferentes métodos de estimativa e sua posterior validação, foram utilizados dois conjuntos de dados experimentais obtidos a partir de medições realizadas nas cultivares Grand Rapids, Regina e Great Lakes. As estimativas de evapotranspiração foram realizadas com os seguintes métodos: Penman-Monteith parametrizado pela FAO, em 1998 (PMF); Penman-Monteith modificado para condições aerodinâmicas características de ambiente protegido (PMAP); Penman-Monteith modificado para ambiente protegido simplificado (PMAPS); Priestley-Taylor (PT); Radiação solar (RS) e Radiação solar simplificado (RSS). Os resultados demonstraram que os métodos PMAP e PMAPS possibilitaram estimativas mais adequadas da ETc, tanto no período da manhã como no da tarde.