Resumo em Inglês:

ABSTRACT The importance of maintaining straw on the soil surface is a subject widely discussed and proven in the literature. However, the effects of this straw on planting efficiency and quality still lack information. In this sense, both time and method of the black oat management influence the permanence of the straw on the soil and, thus, can interfere in the next crop's germination and plantability of the seed drill. This study aimed to evaluate methods and times of black oat management and their implications on the plantability and development of the corn crop in succession in two harvests. A randomized block design with twelve treatments was used, consisting of the combination of three methods of management (crushed, rolled, and desiccated) and four times of management (0, 10, 20, and 30 days before the corn sowing) of black oat straw, arranged in a 3 x 4 factorial scheme, with four replications. The black oat management carried out 30 days before the corn sowing provides the highest corn emergence rate. Management methods that promote greater fragmentation of straw tend to offer less mechanical impediment to seedling development and result in a greater initial and final plant population.

Resumo em Inglês:

ABSTRACT The objective was to study the adaptability and stability of soybean cultivars in the lowland production system under different conditions in a subtropical environment. Fourteen soybean cultivars were evaluated in five locations and three growing seasons in Rio Grande do Sul State, Brazil. Three sowing dates were evaluated in each location and growing season and named as: early, recommended for high yield and recommended to minimize the risk of water deficiency. The experiment was carried out in a randomized complete block design, with three replicates. Yield data was submitted to analysis of variance, and the Eberhart and Russel method was used to study its adaptability and stability. In general, the cultivars that showed adaptability and stability to the three sowing dates showed MG between 5.6 to 6.4 and the type of indeterminate growth. The cultivars A6411 RG, TEC 5936 IPRO and TECIRGA 6070 RR combined wide adaptability and stability, the cultivars Fundacep 65 RR and 6869 RSF RR presented high yield and stability of production and are recommended for lowland environments.

Resumo em Inglês:

ABSTRACT The agronomic traits have complex quantitative inheritance, wheat breeding has a highly cost and time expending to achieve advanced lines, and new cultivars. The objective of this work was to estimate the phenotypic (rp), genotypic (rg) and environmental (re) correlation coefficients and the genetic parameters, as well as to estimate the selection gains between agronomic traits in wheat using multivariate analysis. F6 generation was carried out in a randomized block experimental design, with fifteen wheat genotypes arranged in three replications. The traits measured were days of emergence to flowering, plant height, number of tillers, spike length, number of spikelets, kernel weight and thousand kernel weight. Correlation coefficients, variance components, genetic parameters, selection gain, Euclidiana’s distance, relative contribution of traits and canonical variables were estimated. Selection based on number of tillers, kernel weight and thousand kernel weight may result in expressive selection gains. The number of fertile tillers per plant showed a significant and positive intermediate association with kernel weight and positive correlation with number of spikelets. The cycle showed greater contribution to the genetic divergence among genotypes studied. Distinct groups highlighted the genetic variability among genotypes.

Resumo em Inglês:

ABSTRACT The aim of this study was to analyze whether the use of green manures in association with rock phosphate rates can guarantee corn yields to family farmers. An experiment was conducted with six types of green manures: Mucuna cinereum, Crotalaria juncea, Crotalaria ochroleuca, Cajanus cajan, Pennisetum glaucum and a weedy fallow control treatment; and three rates of phosphorus (0, 50 and 100 kg P2O5 ha-1) in a complete randomized block design. The management with Crotalaria juncea achieved the highest dry mass yield (39.3 Mg ha-1) and in year 2 (2016), with the water deficit during the corn cultivation, led to an increase of the root/shoot mass ratio, as well as presented the lowest water deficit sensitivity index (Ky), indicating that it can be an alternative for managing climate change. The highest corn yield (7510 kg ha-1) was obtained in the management with the Crotalaria ochroleuca, which defines it as a technically and economically viable alternative for family farming, with corn yield exceeding the average yield of the State of Mato Grosso and production cost lower than the average production cost of corn in the State of Mato Grosso.

Resumo em Inglês:

ABSTRACT Strategies for conserving natural resources and reducing agricultural inputs are the great challenge for agriculture, such as sustainable alternatives to control agricultural pests of high economic impact, e.g. plant-parasitic nematodes. This work aimed to evaluate phytonematode’s population dynamics in common bean cultivation grown under crop rotations and no-tillage system. The maize was seeded under pearl millet straw and intercropped with three different crops systems: i) exclusive maize system, ii) maize intercropped with brachiaria and, iii) maize intercropped with crotalaria. The experimental design was a randomized complete block with three treatments (crops systems) and 4 blocks (5 subsamples each block). The common bean was seeded on the straw of exclusive or intercropped maize. The phytonematode population was evaluated in the soil and in the roots in seven moments: (i) fallow; (ii) pearl millet flowering; (iii) pearl millet maturity; (iv) maize flowering; (v) maize maturity; (vi) common bean flowering; and (vii) common bean maturity. The greatest control of the phytonematodes species described in the area was in the maize intercropped with crotalaria treatment, as the phytonematodes population decreased 2.49-fold in this treatment when compared to exclusive maize, resulting in an increase of 11.27% in common bean yield. Therefore, maize intercropped with crotalaria is a viable alternative to reduce phytonematodes infestation in common bean crop.

Resumo em Inglês:

ABSTRACT The best sensorial Brown Turkey figs for the fresh market are the ones harvested soft. However, at this maturity stage, they have a very short shelf life, from two to seven days, depending on environmental conditions, which make their marketing very difficult. This research’s goal was to increase the shelf life of soft 'Roxo de Valinhos' figs, a 'Brown Turkey' plant material grown in Brazil, stored under refrigeration, by applying 1-methylcyclopropene (1-MCP), an ethylene inhibitor. Soft 'Roxo de Valinhos' figs were submitted to 1-MCP at 0; 0.5; 1.0 and 1.5 µg. L-1 for 24 h in airtight, under refrigeration at 4 ± 1 ºC. Subsequently, fruits were stored for up to 17 days at 4 ± 1 ºC. After removing from refrigerated conditions, fruits were kept for one day at room temperature (22 ºC), and then they were evaluated to determine their physical and chemical features. 1-MCP at 1.5 µg. L-1 was able to increase the soft figs shelf life to 12 days.

Resumo em Inglês:

ABSTRACT Witches' broom, caused by Moniliophthora perniciosa, is the most important cacao disease in Brazil, and the final objective of this study is increasing the level and durability of resistance to this fungus, through the association of different alleles or genes favorable to the character, for the generation of new cocoa varieties. It was conducted, for 10 years, the evaluation of the number of vegetative brooms and cushions brooms per plant, of progenies from a cross breeding scheme in North Carolina II design, with the clones: Be 4, Cepec 89, CSul 7, EEG 29, ICS 98, Oc 67, RB 39 and Scavina 6, as group 1 of progenitors, and CCN 10, CCN 51, Cepec 86, ICS 9, IMC 76, Na 33, P4b, and SGu 54, as group 2. For both groups there were differences in terms of the general combining ability and specific combining ability. Differences among progenitors and among progenies were also found for the tendencies in the evolution of the number of brooms over the evaluation period. And it was possible to increase the level and durability of resistance through the association of alleles or genes favorable to this character, all the three results confirming the original hypothesis.

Resumo em Inglês:

ABSTRACT The tomato target spot caused by Corynespora cassiicola may have an important economic impact on tomato production in tropical regions. The objective of this work was to study the effect of different colored plastic films on tomato target spot severity, gas-exchange, and fruit yield. Disease severity, photosynthetic rate, stomatal conductance, transpiration rate, relative chlorophyll content and fruit yield were evaluated in tomato, grown in individual mini-greenhouses covered with transparent plastic films of different colors (clear, red, blue, green, and yellow). At the beginning of the target spot epidemic, the plants under red and blue covers had lower leaf disease infection than those under other colored films (p = 0.013). However, as the disease progressed over time, the effect of the colored films on disease severity become non-significant (p = 0.82), and at the end of the experimental period, the target spot infection was about 70% in all treatments. Photosynthetic rates, stomatal conductance, and transpiration rate were not affected by the plastic film covers; neither the fruit number or fruit production. This study showed that colored films may reduce the infection by target spot, but only in the early stages of disease development (up to ~2% severity).

Resumo em Inglês:

ABSTRACT The particle film technology has been reported as a promising tool in pest control. The objective of this work was to evaluate the efficiency of kaolin-based products against the oviposition of South American fruit fly, Anastrepha fraterculus (Dip.:Tephritidae), and its effect on the quality of citrus fruits. The experiment was conducted in orchards of ‘Okitsu’ tangerine and ‘Valencia’ orange trees in the 2017, 2018 and 2019 harvests. The treatments were as follows: 1) kaolin 10% + 0.1% Break-Thru® adjuvant; 2) Surround® 5% WP; 3) 0.15% phosmet (Imidan® 500 WP), 75 g. a.i.; 4) without application (control). The sprays were performed every 21 days. At harvest, fruits were individually packed in a greenhouse for inspection after 25 days and infestation was recorded. Fruit samples were evaluated for average diameter, average mass, soluble solids, titratable acidity and peel colorimetry. Infestation of A. fraterculus in tangerines was reduced in plants treated with the two kaolin-based products in the 2017 harvest. In the 2017 and 2019 crops, Surround® WP reduced the infestation and the number of puparium/fruits in oranges. The mineral films did not alter the physicochemical characteristics of the fruits, representing a promising alternative for the management of A. fraterculus.

Resumo em Inglês:

ABSTRACT The application of flumioxazin and imazethapyr can affect the interactions between rhizobia and soybean in the rhizosphere. However, it remains unclear the effect of both herbicides, even when applied in mixture, on early nodulation and biological N fixation (BNF) in soybean, mainly related to some important biochemical traits in nodules. This study assessed the effect of flumioxazin, imazethapyr and their mixture on early nodulation and BNF in rhizosphere of soybean. The plant emergence, early nodulation, growth, and N accumulation were evaluated in soybean grown in sandy and clayey soils. The leghemoglobin content and glutamine synthetase (GS) activity were also assessed in fresh nodules. Individually, flumioxazin and imazethapyr did not affect the plant emergence, nodulation and N accumulation in soybean, while the mixture decreased significantly these parameters. Also, the values of leghemoglobin content and GS activity did not decrease with the application of the herbicides individually. The application of herbicides imazethapyr and flumioxazin separately negatively influenced the growth of soybean, while they do not influence the nodulation and N accumulation. However, the use of these herbicides in mixture can negatively influence the early nodulation and N fixation by native rhizobia.

Resumo em Inglês:

ABSTRACT Tifway 419 Bermudagrass is widely used on athletic fields, requiring irrigation and fertilization for its maintenance; however, little information is available for Bermudagrass management in tropical countries, as Brazil. Thus, this study aimed to evaluate the effect of irrigation frequency and nitrogen (N) fertilization on the development of Tifway 419 Bermudagrass. The experiment was carried in 2019, applying two irrigation frequencies (daily and every two days) and five N concentrations of 0, 42.19, 63.28, 105.47 and 126.56 kg N ha-1 divided into three 30-day increments. Photosynthetic pigments, grass height, accumulated dry mass, relative chlorophyll index, regeneration rate, root length, and dry mass of root, rhizome and stolon were analyzed. The best result was observed in between 63.28 and 105.47 kg N ha-1 (15% N) and irrigated every two days. The treatment maintains the green color of the grass. Maximum Bermudagrass regeneration rate was observed within this interval, and the root length and dry mass of roots, rhizomes and stolons were higher compared to the highest concentration.

Resumo em Inglês:

ABSTRACT The Least Limiting Water Range (LLWR) is an indicator of soil physical quality, contributing in information to propose soil management systems in agricultural farming process. This work aimed to assess the usage of LLWR and critical soil bulk density for physical-water quality evaluations, as well as its effect on sugarcane farming under no-tillage and reduced-tillage, in Oxisol. Undisturbed soil samples were collected in 0.00-0.10 and 0.10-0.20 m soil layers, to determine the following attributes: soil bulk density, soil penetration resistance (PR), volumetric water content at field capacity and permanent wilting point and minimum aeration porosity. The LLWR proved to be a good soil physical water quality indicator in sugarcane farming under conservation tillage system. No-tillage presented a greater range of the LLWR when compared to the reduced-tillage, regardless to the PR value adopted as restrictive for sugarcane roots development, increasing the yield of stalks and sugars contents. The critical soil bulk density under no-tillage is between 1.48 and 1.53 Mg m-3 at the RP of 2 and 4 MPa, while under reduced-tillage it is between 1.44 and 1.51 Mg m-3.

Resumo em Inglês:

ABSTRACT A comprehensive knowledge about micronutrient dynamics in leaves and bunches of black pepper is needed in order to proper diagnose nutrient needs, and thus facilitate fertilization management. This study aimed to evaluate micronutrient concentration and accumulation in leaves and bunches of black pepper bunches to understand the crop nutritional demand. The experiment was carried out on in a commercial field of Piper nigrum ‘Bragantina’ located in São Mateus, Espírito Santo, Brazil. Composite samples of leaves and bunches were taken periodically during two crop cycles and the concentration of Fe, Zn, Mn, Cu, and B were assessed. The micronutrient accumulation curves behaved linearly and quadratically, reaching the maximum accumulation point during the time of harvesting. Fe, Mn and B were the micronutrients with highest concentration in both bunches and leaves of black pepper. The nutrient concentration in leaf tissues varied seasonally. These results may contribute to a more sustainable agriculture, in which fertilization rates should consider different needs through the crop stage.

Resumo em Inglês:

ABSTRACT Alternative substrates were evaluated for mycorrhizal inoculants production considering the beneficial effects of arbuscular mycorrhizal fungi (AMF) for plants and environment. The first step of the experiment aimed at evaluating the potential of substrates produced from sugarcane bagasse (SB), coconut fibre (CF) and urban waste compost (UWC) to produce AMF inoculants, by using Brachiaria decumbens as multiplier plant. The experiment has followed a randomized block design, at 7x3 factorial arrangement (seven substrates: SB, CF, SB+CF 1:1, SB+UWC 3:1, CF+UWC 3:1, SB+CF+UWC 3:3:2, Soil+Sand 3:1, vs. three substrate preparations: inoculated/sterilized, inoculated/non-sterilized, non-inoculated/sterilized). Inoculums produced in the first experimental stage were tested at the second stage, based on the inoculated/sterilized preparation. Seed germination, dry shoot biomass, mycorrhizal root rate and total spore production were assessed in both tests. There was significant decrease in seed emergence in organic substrates in relation to Soil+Sand, although the plants growth in organic substrates was greater. Artificial inoculation was not superior to spontaneous substrate mycorrhization or affected inoculum production. Mycorrhizal colonization of roots was equivalent in most organic substrates and in Soil+Sand. However, spore production stood out in organic substrate mixes, mainly when CF and UWC were used. This finding was confirmed at the second experimental stage.

Resumo em Inglês:

ABSTRACT Seed microbiolization has been increasingly contributed to researches due to its beneficial action in the initial growth of seedlings and control of phytopathogens. Thus, the aim of this study was to evaluate the initial growth and control of fungi associated with cowpea seeds by the seed microbiolization with commercial strains of Trichoderma spp. Seeds of cowpea cultivar 'BRS Gurguéia' were analyzed in a completely randomized design, with four replications, using five commercial strains based on Trichoderma asperellum and T. harzianum (Trichodermax®, Quality®, Trichodermil®, Agroguard® and Ecotrich®) and two control treatments, represented by untreated seeds (negative control) and the fungicide carbendazim (positive control). Sanity, germination, emergence and electrical conductivity tests of seeds were carried out to confirm the hypotheses. Seed microbiolization with Trichoderma asperellum and Trichoderma harzianum are effective in reducing the incidence of fungi and have antimicrobial activity similar to synthetic fungicide. The strains T. asperellum T-211 (Trichodemax®), T. asperellum URM-5911 (Quality®) e T. harzianum ESALQ-1306 (Trichodermil®) promote increases for seed vigor. The percentage of seed emergence is maximized with the application of strains T. asperellum (Quality® and Trichodemax®). The commercial strains of Trichoderma tested increase the initial growth of cowpea seedlings cv. 'BRS Gurguéia'.

Resumo em Inglês:

ABSTRACT Propagation of palm trees is mainly by seeds and, in general, germination is uneven and slow, caused by several factors, such as temperature and light. We aimed to evaluate the effect of different temperature conditions and light regimes in the germination of Areca vestiaria and Areca triandra seeds. Two experiments were carried. The experimental design was completely randomized with a 5 × 2 factorial (temperature × light), with four replicates per treatment for the species A. vestiaria and five replications for A. triandra, with 25 e 20 seeds, respectively. The temperatures tested were 25, 30, 35, 20-30 and 25-35 ºC and the light regimes were presence and absence of light. The germination percentage and germination speed index were evaluated. Analysis of variance was performed using the F Test, with subsequent comparison of the means using the Tukey test (α = 0.05). For both species, there were significant differences between the temperature conditions for the studied characteristics. It was concluded that temperatures of 25 ºC, 30 ºC, 25-35 ºC and 20-30 ºC are indicated for germination of seeds of the species Areca vestiaria and, 25-35 ºC for Areca triandra, being the seeds classified as neutral photoblastics.

Resumo em Inglês:

ABSTRACT The coffee leaf miner is responsible for significant decreases in coffee production. To mitigate the problems caused by this pest control strategies need to be applied. The combined application of chemical and biological insecticides is an alternative that can reduce the population of leaf miner in areas with high infestation and occurrence of resistant individuals. The objective of this study was to evaluate the combined application of Isaria fumosorosea and beta-cyfluthrin in the control of coffee leaf miner. A randomized block design was used, in a 4 x 2 factorial scheme, with four treatments: I. fumosorosea, beta-cyfluthrin, I fumosorosea + beta-cyfluthrin and control, besides two application levels, one and two applications. There was no significant effect on the interaction between treatments. The number of applications did not increase the control percentage of the leaf miner. However, the treatments I. fumosorosea, beta-cyfluthrin, I fumosorosea + beta-cyfluthrin showed a higher control percentage of the leaf miner, compared to the control treatment with both one and two applications. I. fumosorosea, beta-cyfluthrin, and the combination of I fumosorosea + beta-cyfluthrin are effective in controlling the leaf miner.