Total Chlorophyll Index Research Articles

Agronomic Performance of RR® Soybean Submitted to Glyphosate Application Associated with a Product Based on Bacillus subtilis

Despite the great benefits arising from the adoption of Roundup Ready® (RR®) soybean, there are reports about the lack of selectivity of glyphosate for this crop. The use of growth-promoting microorganisms can help attenuate the injuries caused by herbicides. The objective of this work was to evaluate the agronomic performance of RR® soybean submitted to the post-emergence application of glyphosate both isolated and in association with Bacillus subtilis. The experiment was carried out in a completely randomized block design, with four replications. The treatments consisted of the post-emergence applications of glyphosate (1296 g a.i. ha−1), glyphosate (2592 g a.i. ha−1), glyphosate/glyphosate (1296/1296 g a.i. ha−1), glyphosate + B. subtilis BV02 (1296 + 42 g a.i. ha−1), glyphosate + B. subtilis BV02 (2592 + 42 g a.i. ha−1), and glyphosate + B. subtilis BV02/glyphosate + B. subtilis BV02 (1296 + 42/1296 + 42 g a.i. ha−1). The application of glyphosate (2592 g a.i. ha−1) and the sequential application of glyphosate provides higher levels of intoxication. The association of B. subtilis BV02 with glyphosate (2592 g a.i. ha−1) prevented losses in the values of relative chlorophyll a and b and the total chlorophyll index. The soybean yield was reduced when the plants were submitted to a sequential application of glyphosate.

ASPECTOS FISIOLÓGICOS DO MARACUJAZEIRO-AMARELO COM USO DE HIDROGEL E MULCHING

ABSTRACT In the Brazilian semi-arid region, water deficit is one of the main factors that compromise the growth and productive yield of crops, including yellow passion fruit, due to the limitation of carbon assimilation by the photosynthetic activity of plants. Therefore, it is necessary to manage the soil with technologies that can reduce the loss of water in the soil and mitigate the effects of water deficit on yellow passion fruit plants cultivated under semi-arid conditions. The objective of this study was to evaluate the application of hydrogel doses and mulching to the soil on the physiological aspects of irrigated yellow passion fruit cultivation. The experiment was carried out in a randomized block design, in a 5 × 2 factorial scheme, referring to five doses of hydrogel (0.0, 0.5, 1.0, 1.5 and 2.0 g dm−3 of soil) in soil without and with mulching from signal grass (Brachiaria decumbens L.). The variables analyzed were chlorophyll indices, fluorescence (initial, maximum and variable) and gas exchange. The total chlorophyll index was increased with the application of 1.5 g dm−3 of hydrogel and the use of mulching; when applying hydrogel doses of 2.0 g dm−3 the photosynthetic rate of yellow passion fruit plants increased, whereas their transpiration rate increased with the use of mulching and doses of hydrogel; as a consequence, there was a reduction in water use efficiency.

Reciprocal recurrent selection for obtaining water-deficit tolerant maize progeny

ABSTRACT: 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.

Heat-tolerant pepper cultivar exhibits high rates of chlorophyll, photosynthesis, stomatal conductance and transpiration in heat stress regime at fruit developing stage

Relevance. Abiotic stress, as heat, significantly affect plant and floral organs growth and development, fruit set, productivity, the quality, and survival of crops. Heat injury occurs when plants are exposed to these temperatures for a long period of time. Depending on the intensity and duration of exposure to the high temperatures, photosynthesis, respiration, membrane integrity, water relations and the hormone balance of the plants may affected.Material and methods. In this study used the commercial pepper cultivar “NW Bigarim” (HT37) released in South Korea and accessions “Kobra” (HT1) and “Samchukjaere” (HT7) selected as heat tolerant and susceptible, respectively. Total chlorophyll index and photosynthetic activities measured using a SPAD meter (Konica, Japan) and portable photosynthesis measurement system (LI-6400, LI-COR Bioscience, Lincoln, NE, USA), respectively.Results. To evaluate the positive effects of high temperature regime (40/28°C day/night, 14/10-h light/dark cycle) on the response of photosynthetic parameters in pepper plants with different heat susceptibility, we measured the total chlorophyll content (CHL) and photosynthetic activities such as photosynthesis (Pn), stomatal conductance to H2O (Gs) and transpiration rate (Tr) in a heat-tolerant (HT1) and -susceptible cultivars (HT7) in comparison with released cultivar (HT37) at fruit development stage. Heat-tolerant cultivars showed higher and more stable index of the CHL, Pn, Gs and Tr than those in heat-sensitive cultivars for 14 days of heat treatment (HT) period. However, the initial index of Pn, Gs and Tr showed significant alteration among pepper plants regardless of thermotolerance rate before HT on day 0 and day 7 after recovery at normal treatment condition (NT) except for CHL, meaning that plants response to high temperature regime is different from that in normal condition. These results suggest that constant high rates of Pn, Gs and Tr as well as of CHL in heat stress condition periods confer to avoid from heat injury during reproductive growth stages.

Yield components and nutritional quality of soybean grain as a function of foliar fertilizers application time

Foliar fertilization aims to provide rapid-absorption nutrients to the plant, supplement soil fertilization, and fulfill the uptake peaks’ demand. This study’s objective was to verify the effect of foliar fertilizers application in stages R2 (full bloom) and R5 (beginning seed) on soybean grain quality, yield components, and grain yield. The experiment was conducted in three sites through Parana state (Brazil) in a 9 × 2 factorial design, with three replications per treatment. Total chlorophyll index, plant height, yield components (number of pods per plant, number of grains per pod, number of grains per plant and thousand-grain mass), protein and oil concentration in the grain, and final yield were evaluated. Plant height, total chlorophyll index, and grain quality were not affected by this study’s foliar fertilizers. Thousand-grain mass responded to the foliar products and the application times. However, no final grain yield effect was observed, possibly because those nutrients’ soil level was adequate.

Chlorophyll concentration and grain production in Avena sativa L. with two doses of nitrogen fertilizer

The productive potential of a crop can be known by indirect measurements of the chlorophyll content. The objective of this research was to evaluate the chlorophyll content and the grain production of the oat crop, in direct sowing, with two doses of rainfed nitrogen and a control without added fertilizer. The experimental design used was randomized blocks with 12 repetitions for grain yield. The size of the plot was 25 m-2. The cultivar used was Estanzuela 1095a and 2 different doses of N were used (25 and 50 kg ha-1). The chlorophyll content in the last fully developed leaf and the grain yield were measured. The results indicated that there were no significant differences in the chlorophyll a and b index as well as there were no differences in the total chlorophyll index and in the ratio of the chlorophyll a / b index. The grain yield and the weight of one thousand grains did not show significant differences.

Sensory analysis of curly kale produced under conventional and hydroponic systems

Abstract The consumption and cultivation of curly kale in Brazil is recent and information on production systems and their acceptance by the consumer are scarce. The aim of this work was to evaluate the sensory characteristics of curly kales cultivated using the conventional and hydroponic systems, considering the treatments: cultivation under the conventional system, without fertilization (A), conventional system with organic fertilizers (C, E) and hydroponic system (F). The harvests were performed at 60, 90 and 120 days after planting for the plants cultivated using the conventional system and at 30 days for the hydroponic system. The total chlorophyll index content and the sensory analyses of ranking of difference and acceptance were analyzed. The lowest chlorophyll index in the curly kales was verified for the one cultivated under the hydroponic system. In the ranking test, the darkest green color was obtained for the curly kale produced using the conventional system and for the attributes aroma, sweet and bitter taste and crunchiness, there was no significant difference.

Nondestructive analysis of photosynthetic pigments in forage radish and vetch

Chlorophylls and carotenoids are the main photosynthetic pigments in plants, and photosynthetic potential can be used to determine the nitrogen fixation or cycling capacity of cover crops. Therefore, this study quantified and compared the content of photosynthetic pigments in Raphanus sativus and Vicia sativa by using two different methods, namely the extraction method and measurements with a portable chlorophyll meter, and determined whether the results of these two methods showed a significant correlation. Photosynthetic pigments were measured, using both methods, in a greenhouse and laboratory, at four developmental stages: the vegetative stages I (30 days after sowing [DAS]), II (60DAS), and III (90DAS), and the reproductive stage (150DAS). The determination of the photosynthetic pigment content in R. sativus and V. sativa, obtained from the extraction method and chlorophyll index, revealed significant differences depending on the developmental stage in both species. Furthermore, the contents of chlorophyll a, chlorophyll b, and carotenoids determined using the extraction method showed high coefficients of correlation with the total chlorophyll index determined using the portable chlorophyll meter. Therefore, the portable chlorophyll meter can be used for the accurate evaluation of the photosynthetic potential of Raphanus sativus and Vicia sativa, which also saves time and reagents.

Estimation and correlation of chlorophyll and nitrogen contents in Psidium guajava L. with destructive and non-destructive methods

Estimating photosynthetic pigments, such as chlorophylls, as well as the foliar nitrogen content is very important for the evaluation of the nutritional and physiological status of a plant. However, producers cannot easily carry out these estimations because they involve analyses in laboratories that are costly and time-consuming. The SPAD-502 total chlorophyll index meter is efficient at rapidly estimating total chlorophyll contents in situ, along with its relationship with the total nitrogen concentration in tissues. The objective of this research was to validate a non-destructive in situ method (SPAD) for use in place of destructive estimation methods for chlorophylls a, b and total, as well as the foliar nitrogen concentration in guava plants (Pisium guajaba L.), cv. Regional Roja, in three phenological stages under the conditions of the municipality of Vélez-Santander (Colombia). The data obtained with the SPAD-502 and the content of chlorophylls a, b and total were adjusted to a second-degree polynomial with correlation coefficients (r) greater than 0.91 for the three phenological stages, while the concentration of foliar nitrogen was adjusted to a linear type model with determination coefficients (R2) higher than 0.90, indicating a highly linear correlation between the non-destructive method and the destructive methods used in the present study.

Seedlings of cassava varieties are responsive to organic fertilization

In Brazil, there is already a recommendation for the production of cassava seed-cuttings for the production of seedlings originated from micropropagation, which may be extended for the production of seedlings obtained from cuttings from healthy plant stems, in order to avoid the spread of diseases. Therefore, it is essential to establish adequate cultivation substrates of easy acquisition which may stimulate the growth of seedlings, both to reduce the nursery period, as well as the seedling’s production costs. The objective of this work was to evaluate the effect of organic fertilizers made from bovine and goat manures, and tree pruning residues, to produce seedlings of three cassava varieties. The plots were set in a completely randomized design, with six replicates. The treatments consisted of three cassava genotypes (BRS Formosa, BRS Tapioqueira and BRS Kiriris) and five proportions of organic fertilizer: soil (0: 100, 20:80, 40:60, 60:40 and 80:20). The evaluations were performed 30 and 45 days after planting (DAP). There were isolated effects for shoot dry mass, total dry mass, leaf area and number of leaves. Interactions were verified for root length, chlorophyll a and total chlorophyll index, root dry mass and shoot dry mas/root dry mass ratio 45 DAP. The organic fertilizer stimulated the initial growth of cassava seedlings in the three varieties studied in the proportion of 50% of organic fertilizer and 50% of Latosol. Varieties BRS Formosa and BRS Kiriris showed the highest Dickson Quality Scores. Genotypes reacted efficiently to organic fertilization and can be propagated on these easily acquisition cultivation substrates.

Non-destructive analysis of photosynthetic pigments in Avena strigosa and Avena sativa

Chlorophylls and carotenoids are the main photosynthetic pigments in plants. The photosynthetic potential of crop plants is used to determine the correct rate of nitrogen fertilization. To date, no studies have been conducted to understand the relationship between different methods of measurement of photosynthetic pigments in oats. The objective of this study was to quantify and compare the levels of photosynthetic pigments in Avena strigosa and A. sativa using two different methods, the extraction method and portable chlorophyll meter, and to determine whether the results of these two methods showed a significant correlation. Photosynthetic pigments were measured using both methods in a greenhouse and the laboratory at four developmental stages: tillering [28 days after sowing (DAS)], vegetative stage I (55 DAS), vegetative stage II (75 DAS), and reproductive stage (120 DAS). The same leaves were used to measure the relative chlorophyll content using a portable chlorophyll meter and extractable chlorophyll using the laboratory extraction method. The readings of the chlorophyll index differed for each developmental stage of both A. sativa and A. strigosa. The contents of chlorophyll a, chlorophyll b, and carotenoids determined using the extraction method showed high coefficients of correlation with the total chlorophyll index determined using the portable chlorophyll meter. Thus, the measurement of chlorophyll using the portable chlorophyll meter can be used for the accurate evaluation of the photosynthetic potential of oats, thus saving time and reagents.

Agronomic Performance of Intacta RR2 Soybean Submitted to Doses of Glyphosate

ABSTRACT: This study aimed at evaluating the agronomic performance of Intacta RR2 soybean submitted to the application of glyphosate doses in post-emergence. For this, two experiments were conducted in two locations (Palotina and Marechal Cândido Rondon - Paraná state). Applications were carried out with increasing rates of glyphosate (0, 720, 1,440, 2,160, 2,880, 3,600, 4,320 g a.e. ha-1), constituting seven treatments with an experimental design in randomized blocks with four replications, totaling 28 plots for each location. The cultivar used for both experiments was Monsoy 6210 Intacta RR2 IPROTM. The analyzed variables were phytotoxicity at 3, 7, 14, 21 and 28 DAA, A-B and total chlorophyll index, final height, number of pods, 100-seed weight, and yield. A regression analysis was used. There was a positive behavior of the linear regression for phytotoxicity and a negative one for final height, number of pods, A-B and total chlorophyll index, and yield in the city of Palotina. In Marechal Cândido Rondon, there were adjustments of the positive linear regressions for phytotoxicity, and negative linear regressions for chlorophyll index, final height, number of pods and yield. Results show that the glyphosate increase from the dose 1,440 g a.e. ha-1 in the studied cultivar damaged the agronomic performance of the culture.

Avaliação fenoprodutiva e teores clorofilianos de rabanete sob fertilização com urina de vaca e cobertura morta

The radish (Raphanus sativus L.) is a short-cycle vegetable that has a rapid demand for nutrients to grow and produce. Because of the small number of reports on organic fertilization with this crop, this work was conducted in the Plant Production Sector of the Course of Agroecology of the Picuí Campus ,IFPB and aimed to evaluate the attributes of growth, yield and chlorophyll index of radish in response to the application of cow urine, via soil, as an alternative fertilization. The experimental design was organized in randomized blocks, with four replications, in a 6 x 2 factorial arrangement, which corresponded to six concentrations of cow urine (0.00%, 0.25%, 0.50%, 0.75%, 1 , 00% and 1,25% - v / v), applied weekly with and without mulch. The variables analyzed were plant height, number of leaves, leaf area, specific leaf area, leaf area index, Falker a, b and total chlorophyll index, longitudinal and equatorial diameters of tuberous roots, fresh tuberous root mass, Axial root length, total dry mass, percentage of commercial tuberous roots, productivity and dry matter yield. The use of mulch reduced specific leaf area, fresh matter and radish productivity, regardless of the concentration of cow urine applied. The leaf chlorophyll index of radish was higher in the plants without mulching. Longer radishes were obtained on substrates without mulching or 0.51% cow urine. Possibly, due to the production of secondary metabolites (allelochemicals) from the mulch (rice straw), the application of 0.54% cow urine without mulching provided higher radish productivity. The concentration of cow urine of 0.38% provided higher yields of dry matter.

Post-emergent applications of isolated and combined herbicides on corn culture with cp4-epsps and pat genes

For optimum yield, it is necessary to incorporate a good weed control into the system. This study aimed to determine the effects of a post-emergent application of different herbicides (individually and combined) on corn presenting cp4-epsps and pat genes. Field studies were conducted on the corn hybrid 2B810 with the cp4-epsps and pat genes in the agricultural years 2012/13 and 2013/14 and included 8 treatments with isolated and combined application of glyphosate, glufosinate-ammonium, and atrazine. The variables evaluated were chlorophyll type a and b, total chlorophyll index, stem diameter, height of the cob insertion, prolificacy index, first height, second height, yield, and volume of 100 grains. The combination of all three herbicides hindered the yield of corn cultures. This practice therefore requires caution when applied to weed management. The combination of two herbicides did not affect the final height or yield and may be a useful method of weed management in future.

Glyphosate affects chlorophyll, photosynthesis and water use of four Intacta RR2 soybean cultivars

The planting of RR2 Intacta soybeans by farmers has been expanding strongly. However, some visual injuries have been noted after glyphosate application. The aim of this study was to evaluate the influence of glyphosate application on chlorophyll, photosynthesis and water use of four Intacta RR2 soybean cultivars. The experiment was conducted in a greenhouse, in a randomized block design with a 3 × 4 factorial scheme, consisting of three glyphosate rates and four soybean cultivars. The glyphosate formula used was isopropylamine salt + potassium salt. The parameters analyzed were phytotoxicity at 7, 14, 21 and 28 days after application, and total chlorophyll index at 0, 3, 7, 14, 21, 28, 35, 42 and 49 days after application. Furthermore, 40 days after application, the net CO2 assimilation rate (A), transpiration rate (E), stomatal conductance (G), and internal CO2 concentration (Ci) were evaluated as well. The water-use efficiency (WUE) and carboxylation efficiency were calculated. The data were submitted to analysis of variance and compared by the Tukey’s test (p ≤ 0.05), followed by regression analysis. The phytotoxicity influence could be seen until 21 days after application, in which Monsoy 6210 IPRO cultivar was the most injured. The increasing doses promoted a reduction of the chlorophyll level up to 35 days after application in Monsoy 6410 IPRO. The cultivars tested here showed similar chlorophyll index values. On the 3rd, 7th and 14th DAA (Fig. 5a–c), there was a significant linear decline in the chlorophyll index with rising glyphosate dose for all four cultivars. The chlorophyll index cultivars were not influenced by the doses on the 42nd and 49th DAA. There was no difference in water use and carboxylation efficiency. The parameters A, E and A/Ci showed a positive correlation as the doses increased, while Ci declined, in both cultivars. The application of glyphosate on these soybean cultivars causes different injuries according to the sensitivity. In general, RR2 soybeans have the ability to recover from visual intoxication injuries and reestablish the normal chlorophyll production and photosynthetic parameters after glyphosate application.

Nitrogen doses in rice grown in a tropical lowland

The rice plant is characterized by having high nutrient demand, being nitrogen (N) the main limiting factor to its productivity. The objective of this study was to evaluate the response of two rice cultivars according to doses of nitrogen fertilization. The experiment was carried out in an irrigated lowland area with hydromorphic soil (humic gleysol) at the region of Formoso do Araguaia-TO, Brazil. The experiment design consisted of five N doses (30, 60, 90, 120 and 150 kg ha -1) applied as urea, and two rice cultivars (Irga-424 and Irga-423). Each experimental plot consisted of twenty-seven lines with 15 m in length, spaced 0.17 m between rows. The useful plot size was made up of four central lines with two linear meters of length. The evaluated characteristics were plant height, number of panicles per m2 , grain yield in kg ha -1, hundred grain mass in g, nitrogen content in dag kg-1, and total chlorophyll index in CFI. Data were submitted to variance analysis and regression at 5% probability by F test. The maximum yield was obtained at a dose of 96 and 126.38 kg N ha -1 for Irga- 424 and Irga-423, respectively. The highest grain yield was 7800 and 5860 kg ha -1 for Irga-424 and Irga-423, respectively.