scholarly journals Competition of maize hybrids with alexandergrass (Urochloa plantaginea)

2019 ◽  
pp. 1447-1455
Author(s):  
Fernando Frandoloso ◽  
Leandro Galon ◽  
Ricardo Luis Gabiatti ◽  
Felipe Bianchessi ◽  
Cinthia Maethê Holz ◽  
...  

Maize is one of the world's major cereals, and alexandergrass is the most damaging weed in the crop. The objective of this work was to evaluate the relative competitive ability of maize hybrids in the presence of alexandergrass through replacement series experiments. The experiments were set up in a complete randomized block design, with four replications. Firstly, for the maize hybrids as well as for the alexandergrass, the plant population was determined in which the final production becomes constant. were composed of plastic pots with a capacity of 8 dm3, and in each experimental unit was placed in the proportion corresponding to each treatment (100: 00, 75:25, 50:50, 25:75 and 0: 100) in each experimental unit, the species competing or not between them. For each hybrid, a separate experiment was considered with the objective of evaluating intra and interspecific competition. The analysis of the competitiveness of the species was carried out through diagrams applied to the replacement experiments and by the relative competitiveness indexes. At 50 days after the emergence of the maize the leaf area (LA) and the dry mass of the aerial part (DM) of the plants were checked. The relative competition was occured among the weed and each maize hybrid, being negatively affected for both of species, independently of the proportion of weed causing reductions in LA and DM of the maize. Interspecific competition causes less damage to LA and DM of species than intraspecific competition. There is basically competition for the same environment resources (water, CO2, sun light and nutrients) between maize and alexandergrass, being the crop more competitive than the weed.

Author(s):  
Henrique Guimarães de Favare ◽  
Sandra da Costa Preisigke ◽  
Leonarda Grillo Neves ◽  
Kelly Lana Araújo ◽  
Milson Evaldo Serafim ◽  
...  

The production of good quality passion fruit seedlings depends on substrates with adequate physical and chemical characteristics. Therefore, this experiment was conducted to evaluate the effect of doses of ash from burning of sugarcane bagasse on improvement of traits of the substrate "gully soil". The experiment was set up in a greenhouse and arranged in randomized block design, in a 2x7x2 factorial scheme. The following factors and their respective levels were studied: (i) soil structure,- aggregating between 4 and 10 mm and <2 mm; (ii) ash doses - 0; 1.5; 3; 6; 12; 24; and 48 t ha-1; (iii) families of passion fruit - F29 and F48. The use of ash combined to the soil with structure <2mm significantly increased the production of shoot fresh mass and shoot dry mass for both families studied. The density of the substrate obtained by the mixture of ash and gully soil (soil) decreased as ash doses increased, regardless of the size of the aggregates and the family studied.


2019 ◽  
pp. 1375-1382
Author(s):  
Tulio Martinez Santos ◽  
Edna Maria Bonfim Silva ◽  
Tonny José Araújo da Silva ◽  
Ana Paula Alves Barreto Damasceno

Soil compaction is a big limitation to food production in agriculture. Wood ash is an agro-industrial residue generated by the burning of biomass in boilers for energy production. It can be used as a corrective agent and fertilizer of the soil. In this context, the objective of this study was to evaluate the root system of safflower cultivated under bulk density levels and wood ash doses in dystrophic Oxisol. The experiment was conducted in a greenhouse with a randomized block design under a 5x5 factorial scheme composed of 5 wood ash doses (0, 8, 16, 24, 32 g dm-3) and 5 bulk density levels (1.0, 1.2, 1.4, 1.6, 1.8 Mg m-3) with 4 replicates. The soil was collected from 0-0.20 m depth layer. Later it was incubated with the respective wood ash doses. Each experimental unit consisted of a pot made of three PVC (polyvinyl chloride) rings, in which the layers of 0.1-0.2 m were compacted. At 75 days after emergence, the plants were cut, their roots washed and the volume and dry mass checked. The results were submitted to analysis of variance and subsequent regression test, both at 5% probability. Soil densities negatively influenced the root system development and culture of safflower. Application of wood ash doses of 20 to 24 g dm-3 significantly improved root development of plant.


2011 ◽  
Vol 29 (4) ◽  
pp. 803-809 ◽  
Author(s):  
G Concenço ◽  
I Aspiazú ◽  
L Galon ◽  
E.A Ferreira ◽  
M.A.M Freitas ◽  
...  

The objective of this work was to evaluate the characteristics related to the photosynthetic ability of hybrid and inbred rice varieties, as a way to assess which of the two presented higher potential to stand out under conditions of competition. The trial was set in a greenhouse in completely randomized block design and 2 x 6 factorial scheme with four replications. Factor A consisted of rice varieties (hybrid or inbred) and factor B by competition levels. Treatments consisted in maintaining one plant of either BRS Pelota (inbred) or Inov (hybrid) variety at the center of the plot, under competition with 0, 1, 2, 3, 4 or 5 plants of the variety BRS Pelota at the periphery of the experimental unit, according to the treatment. Fifty days after emergence (DAE), sub-stomatal CO2 concentration (Ci - mmol mol-1), photosynthetic rate (A - mmol m-2 s-1) and CO2 consumed (DC - mmol mol-1) were quantified, as well as shoot dry mass(SDM).Hybrid plants present higher photosynthesis capacity than inbred plants, when competing with up to 3 times its own density. When under the same competitive intensity, hybrid plants surpass the inbred. However, it should be emphasized that, when in farm condition, the lower competitive capacity with weeds often attributed to the hybrid varieties, probably is due to their lower planting density, but if weed competition is kept at low levels, hybrid rice plants may perform in the same way or usually better than inbred plants.


Author(s):  
E. M. Silva ◽  
R. G. Nobre ◽  
L. P. Souza ◽  
F. W. A. Pinheiro ◽  
A. B. A. Andrade

<p>Além de favorecer o desenvolvimento e a produção das culturas, a adubação tem sido considerada uma técnica capaz de reduzir o efeito da salinidade nas plantas. Neste sentido, desenvolveu-se o trabalho<strong> </strong>para avaliar a influência de doses de nitrogênio na formação de mudas de goiabeira cv. Paluma irrigadas com águas de diferentes salinidades. O experimento foi desenvolvido em casa de vegetação do Centro de Ciências e Tecnologia Agroalimetar da UFCG, Pombal, PB com delineamento experimental em blocos casualizados, em esquema fatorial 5 x 4, sendo os tratamentos correspondentes aos níveis de condutividade elétrica da água (CEa) de 0,3; 1,1; 1,9; 2,7 e 3,5 dS m<sup>-1</sup> associados a 70, 100, 130 e 160% da dose recomendada de nitrogênio (N) para mudas de goiabeira cv. Paluma, com quatro repetições, e cinco plantas por unidade experimental. Aos 180 dias após a emergência, a adubação nitrogenada na dose de 773 mg de N dm<sup>-3</sup> reduz o efeito da salinidade da água de irrigação sobre o diâmetro do caule das mudas. As plantas adubadas com as doses variando de 541 a 618,4 mg de N dm<sup>-3</sup> atingem maior crescimento em altura de planta, número de folhas e área foliar. A área foliar e a massa seca total de mudas de goiabeira atingem maiores valores no nível de CEa de 1,3 dS m<sup>-1</sup>.</p><p align="center"><strong>Effect of nitrogen fertilization in the formation of guava seedlings irrigated with salted water</strong></p><p><strong>Abstract</strong><strong>: </strong>In addition to favoring the development and production of crops, the fertilizer has been considered a technique capable to reduce the effect of salinity on plants. The experiment was conducted in a greenhouse of the ‘Centro de Ciências e Tecnologia Agroalimentar’ of UFCG, Pombal, PB in a randomized block design a 5 x 4 factorial, with the treatments corresponding to the electrical conductivity of irrigation water (ECw) 0.3; 1.1; 1.9; 2.7 and 3.5 dS m<sup>-1</sup> associated with doses of 70, 100, 130 and 160% of recommended nitrogen (N) for guava seedlings Paluma,  with four replications, using five plants per experimental unit. At 180 days after emergence, the nitrogen fertilization at a dose of 773 mg N dm<sup>-3</sup> reduces the effect of irrigation water salinity on the stem diameter of seedlings. The plants fertilized with doses ranging from 541 at 618.4 mg of the N dm<sup>-3</sup> reach higher growth in plant height, leaf number and leaf area. The leaf area and total dry mass of guava seedlings reach higher values at the ECw level of 1.3 dS m<sup>-1</sup>.</p>


2021 ◽  
Vol 34 (2) ◽  
pp. 298-309
Author(s):  
LEANDRO GALON ◽  
RICARDO LUIS GABIATTI ◽  
FELIPE JOSÉ MENIN BASSO ◽  
ANDRÉ LUIZ RADÜNZ ◽  
FRANCISCO WILSON REICHERT JÚNIOR ◽  
...  

ABSTRACT Maize is one of the main cereals cultivated worldwide and wild poinsettia is among the weeds that cause damage in grain production. The objective of this study was to evaluate the relative competitive ability of maize hybrids in the presence of a wild poinsettia biotype through experiments in replacement series. In preliminary experiments, it was determined the plant population in which the dry mass becomes constant. For the maize hybrids ‘Agroeste’, ‘Morgan’, ‘Nidera’, and ‘Velox’, as well as the wild poinsettia, the population was 20 individuals vase-1. Subsequently, experiments were carried out in replacement series in different combinations of species that varied the relative proportions (100:0, 75:25, 50:50, 25:75, and 0:100%). The analysis of the species' competitiveness was carried out using diagrams applied to the replacement experiments and by the relative competitiveness indexes. The height (PH), chlorophyll index (CI), leaf area (LA), and the shoot dry mass (DM) of the plants were evaluated 50 days after emergence. There was competition between the maize hybrids and the wild poinsettia; both were negatively affected, regardless of the proportion of plants, causing reductions in the species' PH, CI, LA, and DM. The competition between maize and wild poinsettia occurs for the same resources in the environment, and interspecific competition caused greater damage to maize and wild poinsettia than intraspecific competition. In general, it was observed that only the hybrids ‘Nidera’ and ‘Velox’ were more competitive than the wild poinsettia.


2016 ◽  
Vol 37 (3) ◽  
pp. 1209
Author(s):  
Núbia Maria Correia ◽  
Leonardo José Petean Gomes

The objective of this study was to evaluate the soybean oversowing with braquiarão (Urochloa brizantha cv. Marandu) and colonião (Panicum maximum cv. Aruana) and the capacity of these forage crops to produce dry mass during the fall-winter-spring period. Two experiments, one for each forage species, were conducted in field conditions in the 2011/2012 season and were repeated in 2012/2013. The experimental set-up was arranged in a randomized block design with four repetitions in a 2 x 5 factorial. The soybean oversowing was studied in the development stages R6 and R8 (2011/2012) or R5 and R8 (2012/2013) with braquiarão or colonião grass in five seed amounts (200, 400, 600, 800 and 1000 points of cultural value – PCV = seeds amount x culture value). In both seasons, the braquiarão oversowing at soybean stages R5 and R6 resulted in higher dry mass production, when compared to stage R8. Additionally, the amount of 600 seeds PCV was sufficient to obtain an excellent percentage of soil cover (&gt;95%), in addition to the satisfactory number of plants per m2 and the dry mass production. On the other hand, independent of the soybean development stage in the oversowing moment, colonião was not promising for use in this sowing type because its low stand and irregular soil covering, even at the higher seed amounts.


2020 ◽  
Vol 44 ◽  
Author(s):  
Juliana Muller Freire ◽  
Letícia Nakamura Veríssimo ◽  
Beatriz Rodrigues Pereira ◽  
Janaína Ribeiro Costa Rouws ◽  
José Carlos Arthur Junior

ABSTRACT The objective of this work was to evaluate the vegetative propagation of Hymenaea courbaril (jatobá) and Apuleia leiocarpa (garapa) using the mini-cutting technique with the use of indolebutyric acid (IBA) growth regulator in different types of mini-cuttings. Two experiments were set up: the first involving the two species and three mini-cutting techniques (basal, intermediate and apical) in the presence and absence of IBA (4000 mg kg-1). In the second experiment, only the garapa species was evaluated by testing the same three mini-cutting techniques at four IBA concentrations: 0, 1000, 2000 and 4000 mg kg-1. The mini-cuttings were obtained from 6-month-old seedlings produced from seeds in a nursery. A randomized block design was used in a 3 x 2 x 3 factorial scheme (three mini-cutting techniques, two IBA concentration levels and three evaluation dates) in the first experiment, and a 3 x 4 x 3 factorial scheme (three mini-cutting techniques, four IBA concentrations and three evaluation dates) in the second experiment. At 90 days, jatobá had an average survival of 54%, with less than 5% of total rooting, without significant influence of the mini-cutting technique or IBA use. Garapa presented higher survival for the basal mini-cuttings in both experiments, which were the only ones that took root. IBA did not influence survival or rooting percentage of garapa mini-cuttings, but negatively influenced the root number, length and dry mass. We concluded that the basal mini-cutting is a viable technique for vegetative propagation of garapa, presenting 40% of rooting, but the propagation by mini-cutting for jatobá was not successful under the conditions of this study.


2020 ◽  
Vol 8 (10) ◽  
pp. 338-349
Author(s):  
Guilherme Gallas Salvalaggio ◽  
Eduardo Franz Berkenbrock ◽  
Jhonatan Rafael Wendling Hartmann Hister ◽  
Eliane Cristina Gruszka Vendruscolo ◽  
Hendrel Vinícius Richter Assis ◽  
...  

The present work evaluated the segregation of the RR-biotechnology and the agronomic performance of maize hybrids originated from three seed categories: single-cross commercial hybrids, double-cross hybrids, and saved seeds (F2 population). The experiment was set up in the field, within a producing area used for market purposes, in São Miguel do Iguaçu, Paraná, Brazil. The research followed a randomized block design with four repetitions. We investigated the following treatments: saved seeds/F2 population (MG 580 PW, MG 30A37 PW, MG 600 PW, and MG 545 PW), seeds of single-cross commercial hybrids (MG 580 PW, MG 30A37 PW, AS 1777 PRO3, AG 9000 PRO3, and DKB 290 PRO3) and home-bred seeds/double-cross hybrids (DKB 290 PRO3 x MG 30A37 PW, DKB 290 PRO3 x DKB 285 PEO3, DKB 290 PRO3 x DOW 2B587 PW, and DKB 290 PRO3 x MG 600 PW). The study considered agronomical characters, as well as the segregation of the RR-biotechnology. The hybrids MG 580 PW and DKB 290 PRO3 were the most productive ones, yielding 9,244.31 and 9,151.84 kg ha-1, respectively. The groups formed by double-cross and F2-population hybrids had the highest average values of RR-biotechnology segregation (20.5% and 13%, respectively). The group of commercial hybrids proved to be superior to the others in all variables appraised, and they also did not show segregation of the RR-biotechnology. The principal component analysis made it possible to sort the three categories of seeds. In conclusion, despite the high cost, the commercial seeds stood out showing the best cost-benefit for maize crops.


2003 ◽  
Vol 60 (2) ◽  
pp. 259-268 ◽  
Author(s):  
Telma Passini ◽  
Pedro Jacob Christoffoleti ◽  
Inês Fumiko Ubukata Yada

Methodologies of competitive interaction quantification between weeds and crops are not widely elucidated and compared in the literature. The competitive ability of common-bean (Phaseolus vulgaris) relative to alexandergrass (Brachiaria plantaginea) was assessed and two approaches of replacement series experiment analysis were compared. The response of the species to the presence of each other at different densities and proportion was evaluated. Replacement series at total densities of 625, 816 and 1,111 plants m-2 were performed at the proportions of common-bean:alexandergrass of 100:0 (pure stand of common-bean), 75:25, 50:50, 25:75 and 0:100% (pure stand of alexandergrass), at four replicates in a randomized block design. Data analyses were performed by the qualitative compared to the quantitative approach. The quantitative approach provided larger number of information than did the qualitative approach, and indicated that there was intraspecific competition among common-bean plants, and a minimum of interspecific competition from alexandergrass. There was no intraspecific competition among alexandergrass plants, being the crop effect on the weed larger than the effect among alexandergrass plants. The ecological niche differentiation was partial, since the crop intraspecific competition was larger than the interspecific, and the last one was negligible, at the same time that the weed interspecific competition was larger than the intraspecific. Common-bean, as a competitor species, is superior to alexandergrass.


2021 ◽  
Vol 34 (2) ◽  
pp. 380-387
Author(s):  
PAULO HENRIQUE SOARES SILVA ◽  
ARTHUR BERNARDES CECÍLIO FILHO ◽  
ISAÍAS DOS SANTOS REIS ◽  
SÉRGIO MANUEL RUGELES REYES ◽  
MARA CRISTINA PÊSSOA DA CRUZ

ABSTRACT Nitrogen is the second nutrient most demanded by arugula. However, the positive effect it has on yield can negatively impact the quality of this vegetable, with negative effects on human health. Two experiments (summer and autumn) were carried out to evaluate the effect of N rates (0, 50, 100, 150, 200 and 250 kg ha−1) on the arugula growth, yield and quality (nitrate content). Each experiment was set up in a randomized block design with four replications. Increasing rates of N reflected positively on leaf N content and thus, higher and desirable values of height, leaf number, leaf area and plant dry mass were obtained in both growing seasons. Consequently, the yield had significant increase, which N was maximized in summer (4.9 kg m−2) and autumn (2.6 kg m−2) and leaf N of 29.4 and 27.0 g kg−1, respectively, at rates of 250 and 213 kg ha−1 and both growing seasons. The higher rate the higher foliar nitrate content of arugula, in summer (2931.3 mg kg−1) and autumn (4218.4 mg kg−1). The foliar nitrate content in both crop season do not reach the risk level to human being heath.


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