A major problem affecting some upland rice cultivars is the increase in plant size when subjected to high doses of nitrogen fertilizer, leading to high levels of lodging. A method to reduce the height of upland rice, and therefore lodging, would be to use plant growth regulators. However, little information exists on the effect of these regulators on plant physiological processes. Therefore, the objective of this study was to evaluate the influence of trinexapac-ethyl application in upland rice via analysis of growth and gas exchange. The experiment was carried out under greenhouse conditions using the BRS Primavera cultivar. A completely randomized design with eight replications was used. Treatments were carried out with and without the application of the plant growth regulator, and plants were subject to two-stage assessments in which physiological and gas-exchange indices were measured. The use of trinexapac-ethyl improved the growth of rice plants from the flowering to the physiological maturity stage, resulting in higher values of leaf area ratio, specific leaf area, and leaf matter ratio in treated plants. At the same time, it provided smaller reduction in net CO2 assimilation at the physiological maturity stage. Thus, net/apparent assimilation rate did not change after the application of growth regulator, but relative growth rate decreased in these treated plants. These results indicate the occurrence of self-shading in rice plants induced by what might be a supra-optimum trinexapac-ethyl concentration.

Lettuce is one of the most produced and consumed leafy vegetables in Brazil. It is harvested when the plant reaches full vegetative growth and the leaves are still tender and there are no signs of bolting. The plant is unsuitable for commercialization after this period, thus, a food that is rich in vitamins, minerals and bioactive compounds such as carotenoid is lost. Therefore, the objective of this work was to assess the purple lettuce quality based on physical-chemical characteristics, in three different ages. The experiment was conducted in an urban community garden in Sete Lagoas MG, Brazil. A completely randomized experimental design was used with three replications. The treatments consisted of three development stages (20, 30 and 40 days after transplanting - DAT). The treatment with 40 DAT presented total carotenoids concentration and soluble solids content significantly higher, lower pH, and darker lettuce, with lower values of the parameter b* (increase in yellow color), and higher values of the parameter a* (increase in red color), compared to the first two treatments. The titratable acidity was statistically equal for the three evaluation periods. Considering the high concentration of carotenoids found at 40 DAT, the harvest can take place at this age.

Rural communities located in the Brazilian Northeast, especially in the semiarid zone, live with water shortages resulting from erratic rainfall. This work proposes the cultivation of saltbush ( Atriplex nummularia ) in the Rural Settlement Project of Boa Fé, Mossoró/RN as alternative to the disposal of reject brine from desalination plant on yield of forage. The statistical design was a split - plot design, being four treatments at the plots, related to irrigation with reject brine water, at different levels of soil moisture by moisture from Field Capacity (FC) (100, 85, 70 and 50% of FC) and in subplots and two levels of organic manure (without fertilized and fertilized) with four replications. The variables of yield and forage quality of saltbush were analyzed. It was observed that saltbush has a great production capacity in terms of fresh matter and drought for saltbush under a level of 85% soil moisture in relation to the field capacity of soil, presenting minimal loss of yield; however, this proved to be productive even with the dry soil. The total yield was satisfactory, showing its viability for forage production.

In two simultaneous experiments, we evaluated the impact of brackish irrigation water and nitrogen (N) fertilization on the production of citrus (scion-rootstock combinations) and its associated gas exchanges. These experiments were conducted at the Campus of Federal University of Campina Grande, Brazil in a protected environment (shade screens on the sides) using drainage lysimeters. Experiment I used a randomized block design (3 replicates), in a 5 × 3 factorial arrangement, corresponding to five water salinity levels (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) and three scion-rootstock combinations: RS1– Common Sunki mandarin (TSKC) × Poncirus trifoliata English (TRENG) - 256; RS2– Common Rangpur lime (LCRSTC); and RS3– TSKC × (Rangpur lime (LCR) × P. trifoliata (TR)) - 059; with Mimo do Céu orange as the scion variety. Experiment II used a randomized block design (3 replicates), in a 3 × 2 factorial arrangement, corresponding to the three scion/rootstock combinations and two nitrogen (N) doses (100 and 200 mg kg-1 of soil). Plants were irrigated with water of 3.0 dS m-1. For both experiments, gas exchanges and mean mass of fruits were evaluated at harvest. Gas exchanges were inhibited in plants under saline stress. Plants grafted with Common Rangpur lime showed greater production potential than did the other genotypes studied, even under brackish water conditions.

The aim of this study was to evaluate different organic substrates and phosphorus doses on the growth and leaf content of nitrogen, phosphorus and potassium in rootstocks of Tamarindus indica L. The experiment was performed in a greenhouse nursery located on the campus of the Universidade Federal Rural do Semi-Árido (UFERSA), from March to October 2013. The treatments consisted of three organic sources at a concentration of 40% (v/v) (bovine manure, goat manure and a commercial organic compound) and four doses of simple superphosphate (0, 0 kg m-3, 2.5 kg m-3, 5.0 kg m-3 and 7.5 kg m-3). The experiment was conducted in a randomized block design (RBD), with 12 treatments (substrates), four replications and 10 plants per plot, totaling 480 plants. The goat manure and the organic compound were the most suitable treatments for the production of rootstocks of the tamarind tree. The maximum dose of 7.5 g kg-1 of simple superphosphate caused the highest levels of phosphorus and potassium in the dry mass of shoots. The nutrients in the dry matter of shoots accumulated in the following order: N > K > P.

The objective of this work was to identify and assess the technological, zootechnical and socioeconomic profiles and identify and quantify benchmarks for dairy cattle production systems, in a non-experimental approach, aiming to contribute to the sustainability and competitiveness of dairy farming in the Pernambuco Agreste region, northeastern Brazil. Thirty-six milk production systems of family and corporate farming were evaluated during twelve months, in order to identify and quantify the benchmarks. The systems were characterized regarding their size and technological, zootechnical and economic profiles. The correlation coefficients of the return rate on invested capital were assessed and regression equations were developed for each indicator, according to four scenarios of annual return rates (4, 6, 8 and 10%). The indicators evaluated were milk production per dairy cows, milk production per area, average price of milk, effective operational cost, total operating cost, total cost per price of milk and profitability. The dairy farming in the Pernambuco Agreste region pays the production costs, but tends to a not adequate remuneration of family labor and a need of external capital input for replacement of the assets. The productivity of production factors area and animals showed higher correlation with cost-effectiveness, denoting the need for increase the production through increases in land area and milk productivity per dairy cow. The identification and quantification of benchmarks may help to identify the weak points of dairy farming in the Agreste region, making it sustainable and competitive.

The passion fruit (Passiflora cincinnata Mast.) is a perennial and drought resistant species that represents a new alternative crop for small farmers in rainfed conditions. This study aimed to evaluate the vegetative and physiological development of passion fruit plants derived from two propagation methods and grown at varied planting spacing. The experiment was conducted from January to June of 2012, in the Universidade Estadual do Sudoeste da Bahia (State University from Southwestern Bahia), in Brazil. It was carried out in a randomized block design under a 2 x 3 factorial scheme, which consisted of two propagation methods (cutting and seeds) and three planting spacing distances within a row (1.5; 3.0 and 4.0 m), however, at same distance between rows (3.0 m), with four replicates and four plants per plot. Cuttings and seeds were sampled from adult plants pre-selected in native areas from Vitória da Conquista - BA, Brazil. Growth (stem diameter and leaf area) and physiological parameters (leaf chlorophyll content, leaf water potential before dawn, relative water content and leaf gas exchange) were assessed on the 90th, 120th and 150th day after transplanting of seedlings into the field (DAT). Based on our results, we concluded that despite plants propagated via cuttings showed most favorable water status, vegetative growth and photosynthetic capacity were lower whether compared to plants obtained from seeds.

Mixed infections in cucurbits are frequently observed in natural conditions between viruses from the Potyvirus genus and Cucumber mosaic virus (CMV), which significantly decreases productivity. The objectives of the present study was to compare the host range of PRSV - W, WMV, and ZYMV isolates and evaluate the effects of mixed infections with CMV in zucchini plants ( Cucurbita pepo L.). Host range studies comprising 23 plant species confirmed some similarities and biological differences among the isolates of PRSV - W, ZYMV, and WMV. RT - PCR confirmed the amplification of DNA fragments of the PRSV - W, WMV, and ZYMV coat protein gene ( cp ) and cytoplasm inclusion gene ( ci ). The virus interaction studies in zucchini Caserta plants indicated synergistic interactions, particularly among species from the Potyvirus genus, and some CMV interference with some virus combinations.

In agroforestry systems, annual plants closest to trees may behave differently from plants in rows that are more distant. This study evaluated the proximity effects of Mimosa caesalpiniifolia (sabiá) and Gliricidia sepium (gliricidia) on corn yield under the taungya and alley cropping systems. The two species were evaluated, in randomised blocks with five replications, in 2010 and 2011, under taungya and alley cropping, respectively. Three rows of corn (left, middle, and right) were grown between two rows of trees. Sabiá trees grew higher than gliricidia trees. The difference in crown diameter between species depended on plant age. There was a linear relationship between plant age and plant height and between plant age and crown diameter for both sabiá and gliricidia trees. In the taungya system, left rows produced more green ears than middle and right rows, but grain yield was higher in middle rows. In the alley system, green ear yield was also higher in left rows than in middle and right rows, but grain yield was unaffected by row position. In both agroforestry systems, there were no differences in corn yield for corn grown between sabiá or gliricidia trees.

The aim of this study was to assess the organic matter changes in quantity and quality, particularly of the humic fraction in the surface layer (0–20 cm), of a Typic Plinthustalf soil under different management of plant mixtures used as green manure for mango (Mangifera indica L.) crops. The plant mixtures, which were seeded between rows of mango trees, were formed by two groups of leguminous and non-leguminous plants. Prior to sowing, seeds were combined in different proportions and compositions constituting the following treatments: 100% non-leguminous species (NL); 100% leguminous species (L); 75% L and 25% NL; 50% L and 50% NL; 25% L and 75% NL; and 100% spontaneous vegetation, considered a control. The plant mixtures that grew between rows of mango trees caused changes in the chemical composition of the soil organic matter, especially for the treatments 50% L and 50% NL and 25% L and 75% NL, which increased the content of humic substances in the soil organic matter. However, the treatment 25% L and 75% NL was best at minimising loss of total organic carbon from the soil. The humic acids studied have mostly aliphatic characteristics, showing large amounts of carboxylic and nitrogen groups and indicating that most of the organic carbon was formed by humic substances, with fulvic acid dominating among the alkali soluble fractions.