Resumo em Inglês:

ABSTRACT The present work aims to evaluate grain productivity, water productivity, and economic water productivity of three soybean cultivars under supplementary irrigation. Two experiments were conducted during the 2018 and 2019 harvests in Santa Maria/RS, Brazil. The experimental design consisted of a random bifactorial block design with six irrigation depths as the first factor and three soybean cultivars (Glycine max L.) as the second. The irrigation system used was the conventional fixed sprinkler, with a fixed irrigation shift of seven days. Crop productivity, water productivity, and economic water productivity were evaluated. The highest productivity was for 100% of reference evapotranspiration (ETo) in both harvests. Maximum technical efficiency was obtained for depths of 73.03% (Harvest 1) and 77.94% (Harvest 2) of ETo. Both harvests presented higher water productivity and economic water productivity in the 50% and 25% ETo depths respectively. Productivity is increased with irrigation, and the economic water productivity is maximized with reduction of depth.

Resumo em Inglês:

ABSTRACT Paricá is a native tree to the Amazon region recognized for several socioeconomic applications. However, there are few studies on the influence of irrigation regime in the seedling stage. Thus, the objective of the research was to evaluate the effect of water depths and irrigation frequency on the development of Paricá seedlings in the edaphoclimatic conditions of the Amazon region. The experiment was conducted in a greenhouse at the Federal Rural University of the Amazon (UFRA), Capitão Poço Campus, located in Capitão Poço, Pará, Brazil. The experimental design was randomized blocks, in 5x2 factorial arrangements, consisting of five irrigation depths and two irrigation frequencies, with four replications. The highest irrigation depth (725 mL) at daily frequency resulted in lowest biomass production maybe due to hypoxia in the root zone. In contrast the every three day irrigation promoted high biomass production with the highest irrigation depth (725 mL). Contrarily, 435 mL depth produces high quality seedlings at daily irrigation frequency. Regarding the rational use of water, producers may use 725 mL at 3-day frequency, given that it has promoted high seedling quality and provides savings of 580 mL compared to the best water depth on the daily irrigation (435 mL).

Resumo em Inglês:

ABSTRACT The objective of this work was to evaluate the physiological variables of the cultivar Opuntia stricta (Haw.) Haw in the first cycle and in the regrowth, under different frequencies of drip irrigation, cultivated in the Agreste da Paraíba mesoregion. Therefore, a randomized block design was used, with 2 treatments (irrigation frequencies) and 4 replications (blocks), with each treatment repeated 3 times within the block (triplicate) totaling 24 experimental plots. For physiological variables, data were evaluated by analysis of variance (ANOVA) and means compared by t test at 5% probability using SAS ® (2002). The present study shows that the stress of environmental conditions had a greater impact on the frequency of irrigation every 28 days, since the forage cactus irrigated every 7 days had the highest internal concentration of CO2; CO2 absorption rate; instant efficiency in water use; intrinsic efficiency of water use; instantaneous carboxylation efficiency, both in the first cycle and in the regrowth period. Respiratory rate and stomatal conductance did not differ between irrigation frequencies for both cycles, showing the good adaptation of the cultivar to the semiarid region.

Resumo em Inglês:

ABSTRACT The use of crop modeling can be useful to understand the interactions between the soil-plant-atmosphere system. The objective of this study was to evaluate sensitivity analysis of the AquaCrop model parameters for wheat crop in the Campos Gerais Region. The varietie tested was TBIO Sinuelo in Castro, Ponta Grossa and Itaberá cities. The analyzed parameters refer to crop phenology, transpiration, biomass production, yield formation, stresses and soil management. The sensitivity analysis was realized varying individually each input parameter in the AquaCrop for the calculation of the Relative Sensitivity Index (SI). The most sensitive parameters of the AquaCrop were: reference harvest index (HIo); water productivity normalized for evapotranspiration and CO2 concentration (WP*); crop coefficient when canopy expansion is complete (KcTR,x); fertility levels; and maximum canopy cover (CCx). The higher sensitivity of HIo and WP* is because they are directly related to two main equations of AquaCrop, linked to the estimates of dry above-ground biomass and yield formation, respectively. The AquaCrop counts WP* reflecting directly on dry above-ground biomass production and on final grain yield. The canopy decline coefficient (CDC) presented considerable sensitivity only in Castro due to the longer duration of the phenological cycle. Fertility levels and saturated hydraulic conductivity (Ksat) in Castro was the least sensitive parameters in the analysis.

Resumo em Inglês:

ABSTRACT Chill is a limiting factor in commercial production of temperate fruit due to their dormancy mechanism. Thus, knowledge of chill requirements of cultivars is important to reach successful production. This study aimed at evaluating responses given by different pecan cultivars subject to artificial chill. Pecan branches were collected from twelve 9-year-old cultivars – Success, Shoshoni, Farley, Elliott, Mohawk, Jackson, Desirable, Barton, Importada, Shawnee, Choctaw and Melhorada – in two orchards located in Canguçu, Rio Grande do Sul (RS) state, Brazil, in 2017 and 2018. Treatments consisted in exposing branches to 0, 250, 500, 750 and 1,000 chill hours in a cold chamber (4.0 ± 0.5 °C) and then taking them to the germination chamber (25 ± 0.5 °C and photoperiod of 16 hours of light) until the end of the evaluations. Final budbreak rate (FBR) of every cultivar and the number of days required to reach 50% of budbreak (DD50%) were evaluated. Chill required by cultivars to start budbreak varied in both years under evaluation. Both FBR and DD50 were higher in 2017 than in 2018. Due to high variation in FBR and DD50, chill requirements of pecan cultivars could not be clearly determined by the biological method.

Resumo em Inglês:

ABSTRACT El Niño-Southern Oscillation (ENSO) is an important source of year–to–year fluctuations in the whole global climate system and in the southern Brazilian climate. El Niño events affect this region, imposing unfavorable weather conditions (rainy/humid/overcast) during critical grapevine phenological stages, compromising yields in the current and following crop seasons. The analysis of 29 crop cycles revealed patterns about grape yield oscillations in Santana do Livramento, Campanha Gaúcha, RS, Brazil. Yield deviations showed correlations with the Oceanic Niño Index (ONI) 3 months running means centered in November. La Niña events correlate with yield oscillations close to or above the tendency line. El Niño events are linked to various results, including the lowest and the highest yields. The four largest crop failures happened in El Niño events, while the three most severe of them happened in cases of early El Niño consolidation. The seven lowest yields were linked to El Niño, or low or descending yields in the previous year (s), or all these factors combined. Simple criteria allowing early warning of crop failure conditions were defined: ONI (or the monthly Niño - 3.4 Index) ≥ +0.5 °C in July (or earlier); and low or descending yields in the previous year (s).

Resumo em Inglês:

ABSTRACT Integrated crop-livestock system (ICLS) can help improve the soil physical attributes, increasing the nutrients cycling and yield potential. We evaluated the effect of forage height management under ICLS on physical soil attributes and water infiltration. Field experiment was carried out for two consecutive years in a randomized complete block design, with three repetitions. Forage was managed under continuous grazing, grazing up to 30 cm (G30), 20 cm (G20) and 10 cm (G10) of height, and control without grazing. Soil bulk density (SBD), microporosity (MIP), macroporosity (MAP), and total porosity (TP) were measured before and after the grazing at 0-5; 5-10 and 10-20 cm layer depth. Water infiltration rate was evaluated using the concentric rings in eight periods (5, 10, 15, 20, 30, 60, 90 e 120 min after beginning of the process). SBD at 0-5 cm layer was not affected by the grazing management, whereas the MIP, MAP, and TP reduced after sheep grazing compared to ungrazed. Water infiltration rate was higher for the G10 management, with greater amount of accumulated infiltrated water. Path analysis showed positive effects of the soil physical attributes under ICLS to the grain yield soybean, allowing the farmers to enhance their profitability.

Resumo em Inglês:

ABSTRACT The correct nutrition of orchards from fertilizer management directly influences fruit yield. Therefore, the objective was to evaluate the nutritional status of orchards of the ‘Montenegrina’ mandarin (Citrus deliciosa Tenore) grafted on Poncirus trifoliata Raf. in southern Brazil. The study included analyzes of soil and leaf tissue from 58 commercial orchards. More than 60% of the orchards were diagnosed with K and Mg insufficiency and more than 30% had an excess of N. There was an insufficiency in Mn and Zn of 60 and 96%, respectively, despite the levels of these micronutrients in the soil being high in both depths studied. In addition, no significant correlations were observed between the contents of a given nutrient in the soil and in the leaves, except for the Ca/Mg ratio. Insufficiency was observed in the leaf contents of K, Mg, Mn and Zn and excesses of N and Cu in the orchards. The use of phosphate and potassium fertilizers requires adjustments due to the excessive content of these nutrients in the soil. Pre-planting acidity correction and soil acidity management in ‘Montenegrina’ mandarin orchards already implanted needs to be optimized.

Resumo em Inglês:

ABSTRACT Late sowings anticipate flowering and decrease the soybean vegetative plasticity. These changes may limit the ability of plants to tolerate leaf area losses. The objective of this research was to evaluate the sowing date effect on soybean tolerance to defoliation at the beginning of pod formation. The experiment was set in Lages (Santa Catarina State, Brazil) during the 2016/2017 growing season. Two sowing dates were tested: November 2, 2016 (preferential) and December 15, 2016 (late). Five levels of defoliation (0%, 17%, 33%, 50% and 67%) of cultivar NA 5909 RG were imposed at the R3 growth stage. Grain yield showed a quadratic response to defoliation, ranging from 4,313 to 6,478 kg ha-1 in the preferential sowing date and from 3,374 to 4,443 kg ha-1 in the late sowing date. The plants tolerated up to 45.6% of defoliation in early sowing and 55.8% in late sowing, without yield losses, in comparison to the control. The highest level of defoliation reduced grain yield by 26.9% and 13.4% in early and late sowings, respectively, compared to the control. The delay of sowing date did not increase the sensitivity of cultivar NA 5909 RG to defoliation at the beginning of pod formation.

Resumo em Inglês:

ABSTRACT Chromium is present in the tannery sludges worldwide making it a problem for agriculture. This study aimed to evaluate whether humus functions as a chromium stabilizing agent when using tannery sludge in the substrate of conilon coffee seedlings (Coffea canephora) and to determine what effects there are on leaf development and anatomy. Treatments consisted of a fixed dose of tannery sludge (30% of volume) on substrates of conilon coffee seedlings with different proportions of humus and subsoil (T-10, T-20, T-30, T-40% of humus). Information for the evaluation of leaf anatomy and seedling development was collected at 180 days after the planting of cuttings. From the phenological point of view, the treatments that best promoted seedling quality were T-30 and T-40. However, the greater the amount of humus in the substrate the greater the absorption of chromium by plants, which directly affected the organization of epidermal cells and leaf mesophyll. In addition, intense cytoplasmic degradation, ultrastructural changes in chloroplasts and mitochondria, and an increase in autophagic vacuoles were observed. We conclude that increasing the amount of humus in substrate with tannery sludge provides higher quality coffee seedlings, despite promoting greater absorption of chromium by plants and the consequent major intracellular disturbances.

Resumo em Inglês:

ABSTRACT The Triplet-Septet (TS) set of melon cucurbit powdery mildew (CPM) race differentials (CPMRD) was established to provide an international means for objective and uniform identification and designation on CPM races. The Area Under Disease Progress Stairs (AUDPS) method for disease progress estimation was derived from the Area Under Disease Progress Curve (AUDPC) method, and both have been used to evaluate disease progress on other crops. We aimed to identify a melon CPM race on the TS melon CPMRD, and estimate disease progress thereon using AUDPC and AUDPS. Plants were inoculated at the 3 to 4 true leaf stage. Severity of CPM infection was evaluated on the 21 TS melon CPMRD at 15, 22, 32, and 41 days after inoculation (DAI) using a visual scale. The CPM population in the greenhouse was identified as race S based on reactions of a set of 11 commonly used melon CPMRD, and it may also be designated as 127.127.126 on the TS melon CPMRD. AUDPS identified higher levels of disease than AUDPC, and its results agreed with those obtained by the commonly used melon CPMRD conventional race identification methods (current and Triplet-Septet). AUDPS can be used to evaluate the disease progress on CPM.

Resumo em Inglês:

ABSTRACT High-throughput phenotyping (HTP) using vegetation indices (VIs) is an important data source for managing plant breeding programs and can be a promising tool in indirect selection. This study hypothesized that VIs are correlated with agronomic traits in corn, and therefore, HTP can be an auxiliary tool for selecting superior genotypes. The objectives were: i) to analyze the association between agronomic traits and VIs, and ii) to identify superior corn hybrids for the evaluated traits using multivariate techniques. Ten corn hybrids (AGRI 330, AGRI 340, FS575PWU, KTZ006VP3, MG545AW, MG580PW, MG711PW, MZ1780, MZ1952, and TROPI 102) were evaluated for plant height (PH), stem diameter (SD), and grain yield (GY). The VIs studied were NDVI, NDRE, EVI, GNDVI, SAVI, and MSAVI. Pearson’s correlation network was constructed to analyze the relationship between the variables, and a canonical analysis was performed to verify the inter-relationship between the variables and hybrids. The VIs evaluated are strongly positively correlated with each other and with PH. The most productive hybrids are MG545AW, FS575PWU and KTZ006VP3. Hybrid MZ1952 has higher correlations with VIs and PH. The findings reveal that VIs can be excellent auxiliary variables for selecting agronomically superior genotypes, being a promising alternative to increase corn breeding efficiency.

Resumo em Inglês:

ABSTRACT The number of experiments that provides greater detail in the differentiation of common bean genotypes for grain physical traits and minerals in cluster analysis is not known. This study was undertaken to determine the number of experiments necessary to more accurately differentiate common bean genotypes for grain physical traits and minerals in cluster analyses. Seven traits of grain physical quality and the concentration of six minerals were evaluated in 17 common bean genotypes with carioca (9) and black (8) grains. Statistical analyses were performed in data obtained from one, two, three and four experiments. A significant genotype × experiment interaction occurred for all traits, except for the potassium concentration. Tocher’s and the unweighted pair group method with arithmetic mean (UPGMA) cluster analyses were efficient in differentiating common bean genotypes by grain type when the data obtained from one experiment were considered. However, the use of data obtained from four experiments made it possible to recognize differences regarding grain lightness and brightness as well as the other traits. Four experiments are need for the Tocher’s and the UPGMA cluster analyses to more accurately differentiate carioca and black bean genotypes for grain physical traits and minerals.

Resumo em Inglês:

ABSTRACT Bacterial spot, caused by Xanthomonas axonopodis pv. passiflorae, is a disease that has limited the cultivation of passionfruit in various orchards in Brazil. The objective of this work is to characterize and evaluate the variability of 29 strains of X. axonopodis pv. passiflorae from different municipalities producing yellow passionfruit in the state of Pará. The characterization was performed by the biochemical methods of KOH solubility, oxidase and Bactray, and the molecular methods of Xapas-F, Xapas-Ri and Xapas-Ro primers. The variability was evaluated by pathogenicity test and RAPD (randomly amplified polymorphic DNA). The strains of X. axonopodis pv. passiflorae were Gram-negative and oxidase-negative, and tests with the Bactray kit showed no relation between the collection municipality and group composition. The Xapas-F/Ri/Ro primers were specific for the strains. The primers used amplified 118 polymorphic bands in the RAPD reactions and the highest genetic similarity was between the strains PA15 and PA16. As the pathogenicity test evidenced a pathogenic variability, the strains PA2.1, PA4.5, PA14, PA4.2, PA4.1, PA4.6, PA3.4 and PA4.3 present the highest severity values for the disease. The strains of X. axonopodis pv. passiflorae show characteristics typical of the species, and genetic and pathogenic variability among them.

Resumo em Inglês:

ABSTRACT The use of rock dust in Brazil has been studied and encouraged to reduce the Brazilian dependence on the foreign market for chemical fertilizers and as an alternative to organic agriculture. The objective of this research was to evaluate the effects of using phonolite rock powder and organic compound, associated with inoculation with the potassium solubilizing bacteria (KSB) of the genus Burkholderia on the chemical characteristics of the soil, macro and micronutrients in the aerial part, and tomato productivity. The experiment was installed in pots in a greenhouse, using a randomized block design in a 5 × 2 factorial arrangement, representing five doses of phonolite added in an organic compound, with the presence or absence of inoculation with the strain 100-13. The nutrient contents in the soil and the aerial part and the production of tomato were evaluated. Differences were observed between the doses of the organic compound and the phonolite associated with the inoculation. The treatments containing the highest doses of an organic compound provided better levels of nutrients in the soil and the aerial part, and in the tomato productivity. The inoculation with the bacterial strain improved the release of potassium from the powder of the phonolite rock.