Abstract
Photo-selective shading screens are emerging practices that aim to combine crop physical protection with different solar radiation filtration to achieve desired physiological responses. The ...objective of the present study was to evaluate the effect of photo-selective shading screens on the growth and physiology of purple lettuce for two transplanting seasons in tropical climate in Brazil. A 2 × 4 factorial arrangement was used, being considered the first factor, the transplanting season (spring and fall), and the second factor is the three 35% shading photo-selective shading screens (red, black and silver) and full sun control. The experimental design was a randomized complete block with four replications. The variables studied were: total fresh matter, total dry matter, leaf number, stem diameter, stem length, leaf area, SPAD chlorophyll index, nitrogen balance indexes, chlorophyll, flavonoids and anthocyanins. The photo-selective shading screens influenced the microclimate and the growth variables of purple lettuce, mainly when these plants were sown in the fall. Planting lettuce during spring may result in lower yields due to the higher investment of plants in secondary metabolites to defend against abiotic stress. According to the results, photo-selective shading screens are an appropriate agronomic technique to reduce phenolic compounds and improve lettuce cultivation conditions and can be implemented within protected cultivation practices to improve crop performance.
Tannery sludge has great potential for use in agriculture, however it is a potentially toxic waste, and it is necessary to establish the ideal dose for each crop. The objective of this study was to ...evaluate the influence of fertilization with liquid tannery sludge on growth, chlorophyll a fluorescence and gas exchange of Pennisetum purpureum in two production cycles. A 2 × 6 + 1 split plot scheme was used, where the first factor was composed of two productive cycles, the second factor different fertilizations doses: 0, 30, 70, 110, 150, 190 t ha
−1
of liquid tannery sludge and an additional treatment with nitrogen, phosphorus and potassium control. Plant height, number of leaves and tillers, canopy and stem diameter, leaf area, dry matter, chlorophyll index (SPAD), chlorophyll a fluorescence and gas exchange were evaluated. The highest production of total dry matter was observed in the second production cycle. The range between 72-100 t ha
−1
of liquid tannery sludge showed the greatest gains in growth and production of elephant grass. At doses above 150 t ha
−1
of liquid tannery sludge, the photochemical apparatus begins to show possible damage to the photosystem II (PSII) and reductions in gas exchange.
In vegetable production, seedling propagation is one of the most important steps as it directly influences the final performance of the plants. In order for such condition, the propagation substrate ...must be in good condition. The objective of this work was to evaluate the effect of different combinations of tannery sludge and urban waste compost as substrates in comparison to the commercial substrate Maxfértil
®
on the growth and quality of eggplant seedlings. The experiment was conducted in a greenhouse using a randomized block design with eight treatments and six replications. The commercial substrate was Maxfértil
®
, a crushed pine bark, with limestone, and seven treatments with increasing proportions of tannery sludge/decreasing urban waste compost (0/100; 10/90; 30/70; 50/50; 70/30; 90/10 and 100/0 v/v). Characteristics of emergence, growth, quality and leaf nitrogen (N) content were evaluated. No difference was found in the emergence of eggplant seedlings among the different treatments used; however, the growth characteristics, quality and N content featured significant effects when the seeds were propagated in alternative substrates. Regression adjustments pointed to an optimal range of 41-49% of tannery sludge associated with urban waste compost for the evaluated characteristics. The strong correlation between SPAD and N content shows its potentiality in detecting N deficiencies in seedlings. The use of tannery sludge residues associated with urban waste compost seems to be an appropriate and sustainable practice for recycling with high agronomic potential.
In view of the need to increase genetic variability to obtain materials with a significant capacity to drought tolerance, this study conducted a cycle of a reciprocal recurrent selection of full-sib ...families of maize. To this end, 64 full-sib families of maize were evaluated in two environments according to their morpho-agronomic data in a randomized block design with two replicates. It were analyzed of Male flowering (MF); Female flowering (FF); Flowering interval (IF); days for flowering (DF); Plant height (PH); Ear height (EH); number of plants at the Stand (NPS); Number of broken plant (NBrP); Number of bedded plants (NBeP); Strawing (St); Ear length (EL); Ear diameter (ED); Ear number (EN); Prolificacy (Pr); Number of diseased ears (NDE); Number of ears attacked by pests (NEP); Ear weight (EW); Yield (YIE) and Total Chlorophyll Index (TCI). The analysis of variance was performed by the F test at 5% significance level, and also the evaluation of genetic parameters. Regarding morpho-agronomic data, the analysis of variance and the analysis of genetic parameters showed that there was no interaction genotype x environment with regard to the genetic variability among the families under study. Lastly, the final selection of the superior genotypes was made on the basis of the ranking of the 40 most productive families, from which, combined with the molecular data, the 30 most productive, most drought-tolerant, and most genetically diverse ones were selected to compose the next cycle of recurrent maize selection aiming water-stress tolerance.
RESUMO: Tendo em vista a necessidade de aumentar a variabilidade genética para obter materiais com significativa capacidade de tolerância à seca, este estudo conduziu um ciclo de seleção recorrente recíproca de famílias de irmãos completos de milho. Para tanto, 64 famílias de irmãos completos de milho foram avaliadas em dois ambientes de acordo com seus dados morfoagronômicos em um delineamento de blocos casualizados com duas repetições. Foram analisados o florescimento masculino (MF); florescimento feminino (FF); Intervalo de florescimento (IF); dias para florescimento (DF); Altura da planta (PH); Altura da espiga (EH); número de plantas na parcela (NPS); Número de planta quebrada (NBrP); Número de plantas com acamadas (NBeP); empalhamento (St); Comprimento da espiga (EL); Diâmetro da espiga (DE); Número de espigas (EN); Prolificidade (Pr); Número de espigas doentes (EQM); Número de espigas atacadas por pragas (NEP); Peso de espiga (EW); Rendimento de grãos (YIE) e Índice de clorofila total (TCI). A análise de variância foi realizada pelo teste F com nível de significância de 5% e também pela avaliação dos parâmetros genéticos. Em relação aos dados morfoagronômicos, a análise de variância e a análise dos parâmetros genéticos mostraram que não houve interação genótipo x ambiente no que diz respeito à variabilidade genética entre as famílias em estudo. Por fim, a seleção final dos genótipos superiores foi feita com base no ranking das 40 famílias mais produtivas, das quais, combinadas com os dados moleculares, foram selecionadas as 30 mais produtivas, mais tolerantes à seca e mais geneticamente diversificadas. para compor o próximo ciclo de seleção recorrente de milho visando tolerância ao estresse hídrico.
Plant resistance to drought stress is a parameter that should be studied with more emphasis in the search for higher agricultural yields. In this scenario, research within breeding programs should be ...directed toward specific mechanisms of action and important agricultural crops in worldwide agribusiness. From this perspective, this study carried out a bibliographic investigation regarding the advances in genetic improvement aimed at drought stress in crops using a hybrid model of analysis of scientific articles. The analysis employed bibliometric parameters for qualitative and quantitative discussion of scientific production and the methodological process of systematic review for the synthesis of the results obtained. The work was divided into four stages: the search for articles in databases, meta-analysis, bibliometric analysis, and systematic analysis. Scientific articles were searched for on the Scopus, Scielo, and Web of Science databases within a 20-year timeframe. Most authors and institutions were from Asian countries, demonstrating the need for global expansion of research on the subject. With regard to the co-occurrence networks between the keywords used in the search, a focus was observed on the following terms: drought resistance, drought stress; drought, and drought tolerance. Evidently, the primary mechanism of tolerance or even resistance studied in breeding programs is associated with the expression of genes and genetically modified organisms that confer resistance to plants. Also, the crops addressed in the research retrieved are highly diverse.
Waste from leather processing, called tannery sludge, has been the focus of many studies into its use in agriculture because its composition is rich in nitrogen and organic matter and has high soil ...reducing power, giving it great potential for agricultural use (Sales et al., 2017; Berilli et al., 2018; Berilli et al., 2020). ...in order to make use of tannery sludge as an alternative source of fertilization for plants, other components that act in the stabilization, structuring and complexation of chromium need to be added to seedling substrate. ...the present study aimed to evaluate whether the association of humus and tannery sludge in the substrate is beneficial for the cultivation of conilon coffee seedlings. ...due to the complexity involving humus ionization potential and chromium valence instability, some questions were raised: (1) Does humus really have the capacity to make chromium in tannery sludge unavailable? (2) Does the use of humus in association with tannery sludge positively affect the development of conilon coffee seedlings compared to conventional substrate? (3) If humus does make chromium unavailable, will the plants show signs of oxidative stress induced by chromium? MATERIAL AND METHODS Experiment implantation This study was conducted at the Federal Institute of Education, Science and Technology of Espirito Santo - Itapina campus, located in the municipality of Colatina, northwestern Espirito Santo State, within the geographic coordinates 19° 32'22" south latitude; 40° 37'50" west longitude and altitude of 71 meters.
Yacon is a perennial herbaceous plant that naturally occurs in South America at altitudes ranging from 2,000 m to 3,100 m above sea level. The yacon culture has recently grown in popularity as it has ...high productive potential in mild climates and multiple benefits to human health. This study aimed to determine the lower and upper base temperatures, cycle duration, and thermal constant for the yacon culture, based on phenological data from field experiments that were carried out during three growing seasons (fall, winter, and spring) in 2013. The experiments were conducted in the municipality of Ibatiba in the state of Espírito Santo, Brazil, in a randomized block design with four replicates. The lower base temperature was determined using methods of the lowest standard deviation in days and degree-days, relative development, and variation coefficient in degree-days for two subperiods: emergence to maturation, and onset of tuberization to maturation. The upper base temperature was determined by the standard deviation and coefficient of variation methods, both in degrees-days. The relationship between meteorological elements and the onset of tuberization was also investigated. The lower base temperature values determined for yacon were 12.5ºC in the two subperiods studied with a base temperature above 34.0ºC. The productivity of these tuberous roots was higher in the fall because of the longer cycle, lower temperature, and lower photoperiod. In turn, a higher thermal sum was needed to initiate tuberization with the delay of planting.
Currently, industries are increasingly concerned about the destination of their waste, and one of the solutions found may be the reuse of certain waste in the form of organic fertilizers. Thus, the ...aim of this work was to evaluate the growth and physiology of conilon coffee seedlings under foliar application of liquid tannery sludge as an alternative to fertilization. The experiment was conduced in a greenhouse. The experimental design was in randomized blocks, with eight replications and seven treatments, which consisted of different concentrations of tannery sludge (6.20, 8.80, 11.47, 14.10 and 17.60 mL of sludge tannery diluted in 1 L of water), a conventional treatment with urea and a control treatment using only water. Growth and physiological characteristics were evaluated through gas exchange, fluorometric analysis and color analysis using the Colorimeter. The conilon coffee seedlings fertilized with 14.10 and 17.60 mL L−1 showed a satisfactory growth pattern. The doses of tannery sludge used in this study did not promote changes in color analysis and indices obtained by fluorimetry, except for flavonoids, in which the highest dose promoted greater synthesis of this secondary metabolite. Doses below 14.10 mL L−1 promoted changes in gas exchange, however, leaf photosynthesis was only compromised with doses equal to or less than 8.80 mL L−1.
Abstract Tannery sludge has been highlighted for substrate use in the propagation of seedlings, combining the solution of an environmental problem with its potential for agronomic use. However, when ...a new fertilizer component enters into the composition of a substrate, it remains to be seen whether other characteristics are affected. Thus, the objective of this work was to verify whether supplementary foliar fertilization is necessary when using a substrate with tannery sludge in the propagation of conilon coffee seedlings of the variety “Vitótria Incaper - 8142”. A 2×13 factorial arrangement was used, the first factor being the presence or absence of conventional leaf fertilization, and the second factor being the 13 coffee conilon Vitoria-Incaper 8142 genotypes arranged in a randomized complete block design with four replications. The genotypes V7 and V9 presented leaves of reduced size, leading to a smaller leaf area, which coincided with a lower accumulation of aerial and total dry matter mass. Higher flavonoid indexes were found in the genotypes V1, V2, V6, and V13, indicating a higher sensitivity of these materials to the components present in the tannery sludge. In general, fertilization provided better initial development as well as a better seedling quality index.
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