Resumo em Inglês:

ABSTRACT The objective of this research was to evaluate leaf temperature, and watermelon yield components under wetted area percentages (PW) in irrigation located in the Agreste region of Northeastern Brazil. Two experiments were carried out in 2018 and 2019. The adopted statistical design was randomized blocks, with six replications and four treatments, in 2018: P1 = 13%, P2 = 14%, P3 = 19%, and P4 = 22%, in 2019: P5 = 12%, P6 = 15%, P7 = 16%, and P8 = 21% of PW. The meteorological variables analyzed were: air temperature (Ta) and rain. The experimental evaluations consisted of measuring the temperature of the plant’s vegetative canopy, tensiometry, mass, and BRIX. Air temperature was not a limiting factor for watermelon growth and development. The average was 195.88 mm, and the average leaf temperature of watermelon is 29.5 °C, a value lower than Ta. There was no statistically significant difference for fruit mass and BRIX, where the overall mean was 10.82 and 10.46 kg, respectively. Therefore, it is feasible to irrigate watermelon with wetted area percentages ranging from 12 to 22%, in localized irrigation systems, without generating physiological damage and reducing agricultural productivity and fruit quality.

Resumo em Inglês:

ABSTRACT Flooding periods directly interfere with the availability of oxygen in the soil, affecting the aerobic processes of the plants. In this study, we aimed to: (i) characterize the effects of water excess soil on cassava growth; (ii) identify management practices that reduce the impact of water excess on cassava yield; and (iii) to know the crop potential yield for the study region in order to quantify the yield loss caused by water excess. The effects of water excess were evaluated through experiments in pots and in the field. The physiological and morphological response of cassava plants under water excess in a controllable environment indicated greater damage to cassava after exposure of 96 and 120 hours of water excess. Every 24 hours of water excess, about 20% of the plants did not emerge and, after 96 hours of excess, the emergence was null. The use of raised seedbeds was a management practice that ensured 62.6% of plant establishment, allowing cassava yields of up to 16.9 Mg ha-1. The potential yield to Santa Maria in the 2018/2019 crop year was 43.9 Mg ha-1 of cassava roots. The yield gap caused by water excess was up to 4.1 Mg ha-1.

Resumo em Inglês:

ABSTRACT In Colombia, the evidence of rootstock/scion incompatibility in avocado cv. Hass graft union has been increasing, generating concern among farmers. The objective was to evaluate the photosynthetic response of the avocado trees due to rootstock/scion compatibility in three locations. A split plots design with a blocking factor per locality was used. The main plot corresponded to the type of graft union (compatible and incompatible) and the subplots to leaf age during the 2020 and 2021 seasons. Climatic (water balance) and gas exchange variables (photosynthesis, transpiration, stomatal conductance, leaf temperature, and efficiency in instantaneous water use) were measured. The results indicate that the photosynthetic performance was not affected when the water balance was negative. Compatibility did not significantly affect gas exchange variables (A, gs, E, Tl, and WUEi) during the main and secondary harvest period. The leaf age/harvest period interaction shows that during the first months of leaf development, A, gs, E, and Tl are greater and are detrimental over time. It is concluded that the rootstock/scion compatibility does not significantly modify the capacity to assimilate CO2. At the same time, the variation in avocado photosynthetic activity depends on the age of the leaves and the harvest season.

Resumo em Inglês:

ABSTRACT This study aimed to analyze the influence of climatic and geographic variables on the flowering process of flood-irrigated rice in the Midwest and North regions of Brazil. Agronomic data from the breeding program were related to the following variables: air temperature, relative humidity, global solar radiation, rainfall, degree days, latitude, longitude, and altitude. The analysis was performed using Multiple Linear Regression (MLR) and Generalized Additive (GAM) models. Cross-validation determined the most suitable model. The GAM model showed the best performance for both regions. In the Midwest and North of Brazil, flowering was strongly influenced by climate variables related to temperature. The rise in minimum temperatures tends to advance flowering. Higher minimum accumulated temperatures tend to delay flowering.

Resumo em Inglês:

ABSTRACT Considering the expressive number of commercial soybean cultivars available for cultivation in Brazil and the constant search for improvements in the production system, the objective was to evaluate the productive components and grain yield and to estimate the correlation between them in soybean cultivars sown in the northwest region of Rio Grande do Sul, during the 2019/20 harvest. Sixteen commercial soybean cultivars were sown under their respective plant density recommendations, in a randomized block design with three replications. At the end of the cultivation cycle, the following variables were evaluated: plant height; height of insertion of the first pod; number of nodes; number of pods with one, two, three and four grains; pods per plant; grains per plant; weight of thousand grains, and; grain yield. The cultivars BMX ZEUS IPRO, NS 5445 IPRO and NS 5700 IPRO presented the highest grain yields, mainly due to the high relationship between the number of pods and grains per plant and the weight of a thousand grains. The indirect selection of more productive genotypes can be carried out through the variables weight of thousand grains, number of pods, grains and nodes per plant, given the significant positive correlation between them.

Resumo em Inglês:

ABSTRACT The seeds and seedlings morphological differentiation is a challenge in the early stages of plant growth. This study aims to describe the physical and morphological characteristics of seeds and seedlings of Jatropha mollissima to delimit differences between other species from the same genus. The seeds were placed to germinate for morphological description and their physical characteristics were measured. The J. mollissima presented a 1000-seed weight of 332 g, 3,008 seeds per kilogram, 6.7% of moisture, 1.29 cm length, 0.84 cm width, and 0.66 cm thickness. We verified that the seeds are oval in shape; their colour is dark brown, greyish or mixed colour; they have visible raphe and hilum, and caruncle with beige coloration. The endosperm is oleaginous and involves the embryo with foliaceous and spatulate cotyledons. The embryo is axial, and the hypocotyl-radicle axis has a short cylindrical shape. Germination is epigeal and phanerocotyledonary; leaves have dimorphism and serrated margins with simple trichomes; and their apex is cuspidate or attenuated. Our research demonstrates that it is possible to differentiate J. mollissima from other species of the same genus through morphological characteristics. Therefore, this work contributes to the correct identification of the species, laboratory analysis, and field recognition.

Resumo em Inglês:

ABSTRACT Tomato bacterial spot caused by Xanthomonas hortorum pv. gardneri triggers significant losses in crop production, and the active ingredients availability for disease control is limited. For this reason, there is a great demand for plant protection alternatives, such as the use of nanocrystals. Thus, the aim of this work was to evaluate the performance of nanocrystals spraying intervals for the control of tomato bacterial spot. Tomato plants of cv. Santa Cruz Kada were sprayed at 3-4 leaf stage under greenhouse conditions with ZnO:1Mg, ZnOCl, and ZnOCl:0.1Cu nanocrystals, copper and water. Three days later, the plants were inoculated with a bacterial suspension (109 CFU mL -1). Then, after 3, 6, 9, or 12-day intervals, the plants were sprayed with the products. The bacterial spot severity was periodically quantified as affected leaf area percentage, and the area under the disease progress curve was calculated. Nanocrystals ZnO:1Mg, ZnOCl, and ZnOCl:0.1Cu reduced the tomato bacterial spot severity when sprayed at 3- and 6-day intervals. Thus, nanocrystals may be used for the tomato bacterial spot control when sprayed at 6-day intervals, once this interval is adequate and practical for disease management.

Resumo em Inglês:

ABSTRACT Watermelon has great importance due to its nutritional properties. The aim of this work was to study accessions classified as resistant to fusariosis. Twelve accessions and two cultivars, Sugar Baby and Charleston Gray (controls), were characterized for watermelon fruit quality descriptors. The experiment was conducted in Petrolina-PE, over two production cycles in a randomized complete block design, with three repetitions and five plants per plot. Two fruits per plot were sampled for characterization. Ten quantitative and seven qualitative descriptors were evaluated. For the qualitative traits, dissimilarity measures were determined by a matrix of Euclidean distance. At the second harvest, most accessions had higher organic acid and vitamin C content in the pulp and higher soluble solids (°Brix) content. The accessions were divided into four groups according to the Tocher method. There is variability among the evaluated accessions, and the accessions BGH-Univasf 40, BGH-Univasf 169, and BGH-Univasf 177 are potential sources for use in watermelon breeding programs. Accessions BGH-UNIVASF 76, BGH-UNIVASF 128, and BGH-UNIVASF 185 (Citrullus lanatus var. citroides) performed well in terms of total production, fruit mass, and vitamin C content.

Resumo em Inglês:

ABSTRACT We hypothesized that common ragweed has rapid growth and development in shoots and roots, which explains its high potential for establishment in the areas, as well as the high regrowth capacity after cutting or application of contact herbicides. This study aims to evaluate the growth of the specie Ambrosia artemisiifolia. The treatments consisted of collection periods of common ragweed plants at fixed intervals of ten days, from 15 to 95 days after emergence (DAE), totaling nine evaluations. In each collection, the aerial part and the roots were evaluated. In the aerial part, stature, leaf area, number of leaves, and dry mass were evaluated. From these data, the absolute growth rate, relative growth rate, net assimilation rate and leaf weight ratio were calculated. The length, surface area, volume, average diameter, number of root tips, and dry mass were evaluated in the root. The common ragweed plants show rapid growth after emergence, with a similar response in aerial parts and roots. The potential for competition with crops is expressive. Furthermore, due to growth and development characteristics, the potential for regrowth is high and impacts the difficulties in controlling this species. Thus, the authors indicate that control should be carried out within a maximum of 25 days after emergence.

Resumo em Inglês:

ABSTRACT Hail netting increases natural fruitlet drop. Mixing lower concentrations of Plant Growth Regulators (PGRs) and spraying on more advanced fruitlets could promote adequate crop load management and improve fruit quality. The objective of this study was to evaluate thinning programs with low concentrations of PGRs sprayed at advanced fruitlet size looking for reducing crop load, enhancing fruit quality, and preserving yield. On 2020/21 and 2021/22, in an orchard covered with hail netting in Bom Jesus-RS, eight programs were tested on vigorous ‘Maxi Gala’: Benzyladenine (BA)+Gibberellic acid4+7 (BA-GA) at full bloom (FB) and BA+Ethephon (ETH) at 15mm; BA-GA at FB and Naphthalene acetic acid+Carbaryl (CB) at 7 mm; BA-GA at FB and BA+CB at 15 mm; ETH+CB at 15 mm and Metamitron (MM)+ETH at 20 mm; BA-GA at FB and BA at 7 mm and MM at 20 mm; MM at 7 mm and MM at 20 mm; Manual Thinning Only; Untreated Control. The treatments containing CB reduced fruit set, although diminished yield unsustainably. All PGR programs improved fruit quality. In conclusion, BA-GA at FB and BA+ETH at 15 mm, and MM at 7 mm and MM at 20 mm reduce crop load, preserve yield and improve fruit quality.

Resumo em Inglês:

ABSTRACT Maize landraces diversity is important for many smallholder and indigenous populations. Gene flow constitutes a threat to the genetic conservation of several locally adapted maize landraces and, risk management depends on monitoring transgenic occurrence in non-GM maize. This study evaluated the occurrence of exogenous proteins from GM-maize in maize landraces and teosinte cultivated in the Alto Jequitinhonha region, State of Minas Gerais. Gene flow from GM maize to non-transgenic varieties was evaluated in eight maize groups and one teosinte variety. A transgenic maize variety was used as a positive control. Proteins Cry1F and Cry2Ab2 were monitored using the Protein Detection Assay kit (Envirologix QuickStix® kit protocols for detecting Cry1F and Cry2Ab2 proteins). Transgenic proteins were not detected in the leaves of landraces and teosinte cultivated in the Alto Jequitinhonha region.

Resumo em Inglês:

ABSTRACT The objective of this study was to (i) use a combination of a definitive screening design (DSD) and a complete 33 factorial design to estimate the effects of four fertilizer supplements (factors) screened in the 1st planting cycle of Prata Gorutuba banana trees and (ii) determine whether combinations of these four factors can be identified for a future test. A DSD was combined with a complete 33 factorial scheme composed of three factors with three levels (application doses) each and three extra repetitions of the central level (commercial dose), totaling 30 experimental plots (27 + 3). The experimental area was divided into six blocks in a randomized block design (RBD) with 5 experimental plots each. The four selected factors included three soil conditioning products and a biostimulant based on seaweed extract. Experimental efficiency was maintained by performing a single trial with only 35.71% of the number of total plots used in the previous screening experiment. The results corroborated the main hypothesis of the study, i.e., that the most important factors previously screened in a previous trial could be maintained with three dose levels without altering the cultivation performance.

Resumo em Inglês:

ABSTRACT Considering that the expression of sweetpotato characters may vary according to the environment, we aimed to evaluate the nutritional performance of nine genotypes in two different regions. Experiments were carried out in Itabaiana, SE and Gama, DF, in 2015/2015 and 2015/2016 crop years. The experimental design was a four-replicate randomized block design of 10 plants per row, spaced 75 cm between rows and 40 cm between plants. The treatments were the Beauregard cultivar and eight clones 6, 8, 9, 33, 50, 66, 75, 79; in addition, two local cultivars (Olho Roxo and Ourinhos) were used as controls for sugar analysis. They were evaluated for dry matter, total carotenoid and betacarotene content; and the content of fructose, glucose, sucrose, and total soluble solids. Total and soluble sugars evaluations were performed only in 2015/2016. The resulting data underwent analysis of individual and pool variances, simple correlation, and grouping of treatment means by a Scott-Knott test. It was verified that dry matter, brix, total carotenoids, betacarotene, and sugar (fructose and glucose) levels were different in Itabaiana-SE and Gama-DF evaluations. These findings demonstrate the importance of regional validations of sweetpotato quality traits under different Brazilian conditions.

Resumo em Inglês:

ABSTRACT In economic terms the lettuce (Lactuca sativa L.) is considered relevant among the vegetable crops. The diversity of cultivars available today, their varying climatic requirements and climatic differences between the different producing regions, lettuce may present seasonal variations in supply and prices during agricultural years. The aim of this work was to study the seasonal variation of lettuce supply and prices practiced in the state of Minas Gerais, in the period between January 2012 and December 2017. The data were obtained from CeasaMinas and processed by the centralized moving geometric mean methodology, obtaining the minimum, average and maximum indexes for supply and prices practiced. Lettuce showed a marked seasonal variation in supply and prices, and Ceasa Great-BH presented the highest seasonal variation of price and supply indices practiced. The variations in supply and prices in the hot and rainy season, in relation to the dry season, are markedly more accentuated. It was observed that there is a relationship that follows the “Law of supply”, where in the cold periods of the year the lowest prices associated with the lowest offers were presented and in the hot periods of the year, the highest prices associated with the largest offers were presented.

Resumo em Inglês:

ABSTRACT Canola has considerable global significance in edible oil and biodiesel production. In Brazil, canola has adapted to the temperate South region, where production is now concentrated. However, research indicates potential for growing the crop in warmer regions. This study evaluated the performance of canola hybrids under growing conditions in the Campo das Vertentes mesoregion, Minas Gerais, during the 2019 and 2021 harvests. The experiments were conducted in a randomized block 6 × 6 factorial design, with four replicates. Six canola hybrids, Hyola 433, Hyola 575 CL, Nuola 300, Hyola 571 CL, Diamond, and ALHT B4, and six sowing dates: 02/15/2019, 02/28/2019, 03/20/2019, 04/09/2019, 02/22/2021, and 03/11/2021 were tested. The plant height, total number of siliques per plant, number of grains per silique, grain yield, and canola oil yield were evaluated. The Nuola 300 and Hyola 575 CL hybrids showed superior grain and oil yields, indicating potential success in growing in the Brazilian Cerrado region. Findings indicated an optimal sowing period in the Campo das Vertentes region until March. These results stress the importance of strategically selecting hybrids and sowing timelines to maximize canola yield in the region under study.

Resumo em Inglês:

ABSTRACT Knowledge on the viability of the seeds is important in the management of the Germplasm Bank, as it allows monitoring the longevity and the need for regeneration of the accessions. The objective was to validate the efficiency of the Gomez-Campo methodology for seed conservation by evaluating physical dormancy and physiological quality of 11 Stylosanthes spp. accessions stored between seven and 13 years in the Forage Germplasm Bank of the State University of Feira de Santana (FGB-UEFS). One-hundred seed were used to determine moisture degree (%) and the viability with the descriptors: percentage of germination (G), germination speed index (GSI), synchronicity (Z) and average germination time (AGT). Sowing was done in plates moistened with water, arranged under controlled conditions (BOD chambers: at 20/30 °C and 12 hours/light) and in a completely randomized design in a 2 x 11 factorial scheme (scarified/non-scarified seeds and 11 accessions). After 14 days, it was observed that most of the accessesion presented high G (greater than 70%), GSI less than 2 seeds.day-1, Z with a mean value of 0,52 and AGT with a mean value of 2 days, characterizing a synchronous and rapid event. Thus, the methodology used in storage is efficient for the conservation of Stylosanthes seeds in the medium term.

Resumo em Inglês:

ABSTRACT With the objective of evaluate the use of residues as growing media for the yellow passion fruit seedlings, a randomized block experiment was carried out with treatments distributed in a 2 × 21 factorial scheme corresponding to fertilizer management (presence and absence of controlled-release fertilizer), and combination of growing media from five local agro-industrial wastes (bark of cupuaçu fruit, almond shell of castanha-do-brasil, lumps of acerola fruit, lumps of cajá fruit, and lumps of açaí fruit) and a commercial growing media, which tested pure and was combined in a 1:1 ratio. The variables measured were the seedling height; stem diameter; height: stem diameter ratio; number of leaves; shoot, root, and total dry matter; and Dickson quality index. The dates were submitted to univariate and multivariate analyzes. The pairwise combination of growing medias produced from the bark of cupuaçu fruit, almond shell of castanha-do-brasil, lumps of acerola fruit, lumps of cajá fruit, lumps of açaí fruit, and commercial growing media in a proportion of 1:1 and with the use of controlled-release fertilizer constitute an alternative for other growing medias in the production of yellow passion fruit seedlings.

Resumo em Inglês:

ABSTRACT Paraná leads the Brazilian production of beans so that the cultivation system can restrain the root development of the plants. Limestone and agricultural gypsum can be alternatives to stimulate the development of roots, and it is necessary to establish criteria for their use. The objective of this work was to evaluate the development of bean plants subjected to liming and gypsum doses in a typical Dystrophic Red Argisol. The experiment was carried out in Umuarama, state of Paraná in PVC tubes (80 x 15 cm), growing Phaseolus vulgaris cultivar Pérola for 90 days. Treatments consisted of gypsum doses (0, 420, 670, 950, 1140, 1430, 3000, and 5320 kg ha-1) combined or not with lime application, in a factorial design (8 x 2) with four replications. At the end of the cycle, the aerial part of the plants and soil samples were collected for analysis. Gypsum doses benefited bean development, especially when associated with liming, which raised pH, Ca+2, and Mg+2 and reduced Al+3 in the soil. The doses of maximum technical efficiency of gypsum were 3291 and 2991 kg ha-1 for the treatments with and without liming, respectively, also increasing the Ca+2 and available P concentration in the soil.