scholarly journals Desempenho morfofisiológico de cultivares de soja de ciclo médio em condições de alagamento do solo

Author(s):  
Marcos Paulo Ludwig ◽  
Sandro De Oliveira ◽  
Luis Osmar Braga Schuch ◽  
Francisco Jesus Vernetti Junior ◽  
Rogério Seus ◽  
...  

<p>O aumento no cultivo de soja no Brasil têm atingido áreas antes utilizadas para outros fins, como em regiões de solos de várzea, estando assim, sujeita a eventuais alagamentos do solo. Este trabalho objetivou avaliar alterações morfofisiológicas em cultivares de soja de ciclo médio, em condições de alagamento do solo, nos estádios fenológicos vegetativo e reprodutivo para recomendação de cultivares. Os experimentos foram conduzidos na Estação Experimental de Terras Baixas, da Embrapa Clima Temperado em Capão do Leão, RS. Foram aplicados três sistemas de manejo da água: condição normal de cultivo (sem alagamento), alagamento no período vegetativo (V3/V4) e alagamento no período reprodutivo (R2/R3). As avaliações realizadas durante o ciclo da cultura foram: altura de plantas, diâmetro da haste principal, índice do teor de clorofila, fenologia e número de nós nas hastes por planta. O alagamento do solo reduz o número de nós na haste principal, reduzindo a estatura das plantas, sendo os efeitos mais acentuados quando o alagamento ocorre no estádio vegetativo. Além disso, o alagamento do solo no período reprodutivo promove aumento do diâmetro da haste principal. O alagamento do solo causa retardamento de ocorrência dos estádios fenológicos, bem como do ciclo total das cultivares de soja.</p><p align="center"><strong><em>Morphophysiological performance of medium cycle soybean cultivars under flooding</em></strong><strong><em></em></strong></p><pre><strong>Abstract: </strong>The increase in soybean cultivation in Brazil has reached areas previously used for other purposes, such as in regions of lowland soils, thus being subject to possible soil flooding. This study aimed to evaluate morphophysiological changes in medium cycle soybean cultivars, under soil flooding conditions, in the vegetative and reproductive stages to recommend cultivars.<strong> </strong>The experiments were conducted at the Estação Experimental de Terras Baixas, EMBRAPA Clima Temperado in the Capão do Leão city, RS. Three water management systems were applied: normal cultivation condition (without flooding), flooding in the vegetative stage (V3 / V4) and flooding during the reproductive stage (R2 / R3). During the crop cycle, plant height, diameter of the main stem, chlorophyll content index, phenology and number of nodes in the stem per plant were collected. On the basis of the results this study, it can be concluded that he flooding reduces the number of nodes on the main stem, reducing plant height, with the most pronounced effects when flooding occurs in the vegetative stage. Furthermore, flooding the reproductive stage promotes increased diameter of the main stem. Flooding causes delay of occurrence of phenological stages and the total cycle of soybean cultivars.</pre>

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Greta G. Gramig ◽  
David E. Stoltenberg

Field experiments were conducted to determine whether exposure to reduced red : far-red light ratios (R : FR) typical of crop–weed environments was associated with adaptive changes in morphology, productivity, and fecundity of common lambsquarters. Plants were grown in reduced or ambient R : FR environments (both in full sunlight) until initiation of flowering, after which plants were grown in full sunlight or partial shade. At initiation of flowering, plants that had been exposed to reduced R : FR exhibited greater specific leaf area, stem elongation, main stem leaf area, specific stem length, and main stem mass compared with plants exposed to ambient R : FR. However, biomass allocation to stems, leaves, and roots did not differ between vegetative-stage R : FR treatments. At the end of flowering, morphology and productivity of plants exposed to partial shade did not differ between vegetative-stage R : FR treatments. In contrast, plants exposed to full sunlight during flowering after exposure to reduced R : FR during the vegetative stage had less total plant mass, less total leaf area, greater stem elongation, greater specific stem length, and a greater ratio of main stem to total stem mass compared with plants exposed to ambient R : FR during the vegetative stage. At physiological maturity, plants exposed to reduced R : FR during the vegetative stage and to partial shade during the reproductive stage had less total seed mass and fewer seeds compared with plants exposed to ambient R : FR during the vegetative stage and to partial shade during the reproductive stage. Fecundity of plants exposed to full sunlight during the reproductive stage did not differ between vegetative-stage R : FR treatments. These results indicate that exposure of common lambsquarters to reduced R : FR during the vegetative stage was maladaptive at later stages of growth in competitive environments, and suggest that interactions of light quality and quantity are important determinants of common lambsquarters fecundity.


2012 ◽  
Vol 7 (12) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Lili Huang ◽  
Hong Wang ◽  
Hechun Ye ◽  
Zhigao Du ◽  
Yansheng Zhang ◽  
...  

cDNAs encoding Hypericum sampsonii benzophenone synthase (HsBPS) and chalcone synthase (HsCHS) were isolated and functionally characterized. Differential expressions of HsBPS and HsCHS were monitored using quantitative polymerase chain reaction (PCR). In the vegetative stage, HsBPS was highly expressed in the roots; its transcript level was approx. 100 times higher than that of HsCHS. Relatively high transcript amounts of HsBPS were also detected in older leaves, whereas the youngest leaves contained higher transcript amounts of HsCHS. In the reproductive stage, maximum HsCHS expression was detected in flowers, the transcript level being approx. 5 times higher than that of HsBPS. The inversed situation with a 10-fold difference in the expression levels was observed with fruits. High transcript amounts for both proteins were found in roots.


2020 ◽  
Vol 8 (3) ◽  
pp. 63
Author(s):  
Priscila Pereira Sacramento ◽  
Letícia Cunha da Hungria ◽  
Jamil Chaar El-Husny ◽  
Luis De Souza Freitas

The aim of this study was to evaluate the influence of planting density and cultivar of soybean on yield components in the southeast Amazon. The experiment was carried out in an Oxisol, with a randomized block design in a 2 x 4 factorial scheme. The treatments were two soybean cultivars (BRS 9090 RR and BRS 8990 RR) and four planting densities (13, 15, 18 and 20 plants m-1), with three replications. First pod insertion height (IFP), plant height (H), number of pods per plant (NPP), grain yield (Y) and weight of 100 grains (W100) were evaluated. The insertion height of the first pod showed a tendency of increase with the increment of plants per linear meter for cultivar BRS 8990 RR, different of the behavior observed for the cultivar BRS 9090 RR, which only showed difference when the density of 300.000 plants ha-1 was tested. For plant height, among soybean cultivars, there was only difference in D400, with BRS 8990 RR showing a maximum height of 83.3 cm, 21% higher than BRS 9090 RR. When evaluated under D350, BRS 8990 RR showed an increase of 13% in the number of pods compared to BRS 9090 RR. Both cultivars showed linear behavior for the grain yield, increasing according the plant population, with the highest grain yield obtained under the density of 400.000 plants ha-1 (4527.3 kg ha-1). The weight of 100 grains was not influenced by any variation factor.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 916
Author(s):  
Innocent Maseko ◽  
Bhekumthetho Ncube ◽  
Samson Tesfay ◽  
Melake Fessehazion ◽  
Albert Thembinkosi Modi ◽  
...  

African leafy vegetables (ALVs) are nutrient dense and can contribute to crop and dietary diversity, especially in water-stressed environments. However, research on their productivity under limited water availability remains scant. The objective of the study was to evaluate growth, physiology and yield responses of three ALVs (Vigna unguiculata, Corchorus. Olitorius and Amaranthus cruentus) and a reference vegetable (Beta vulgaris var. cicla) to varying water regimes [30%, 60% and 100% of crop water requirement (ETc)]. Field trials using a randomised complete block design, replicated three times, were conducted over two summer seasons, 2015/16 and 2016/17. Leaf number, plant height, chlorophyll content index (CCI), chlorophyll fluorescence (CF), and yield were measured in situ. For A. cruentus and C. olitorius, water stress (30% ETc) was shown to produce a lower yield, although leaf number, plant height and chlorophyll content index were unaffected, while for B. vulgaris, leaf number and yield were reduced by water stress. For V. unguiculata, CF, CCI, plant height, leaf number, and yield were not affected by water stress, indicating its suitability for production in water scarce environments. Using 60% ETc was suitable for the production of A. cruentus, C. olitorius and B. vulgaris var. cicla, whereas 30% ETc is recommended for V. unguiculata. The yield results of V. unguiculata indicate that it performs better, while the yield of A. cruentus and C. olitorius is comparable to that of B. vulgaris under similar conditions, indicating potential for marginal production.


Weed Science ◽  
1973 ◽  
Vol 21 (4) ◽  
pp. 279-281 ◽  
Author(s):  
R. J. Smith ◽  
C. E. Caviness

Ten commercial soybean [Glycine max (L.) Merr.] cultivars were evaluated for reaction to over-the-top applications of two rates of 3′,4′-dichloropropionanilide (propanil) at the growth stage when three nodes on the main stem had completely unrolled leaves. Propanil, a herbicide commonly applied to rice [Oryza sativa L.] for control of grass weeds, was applied at 0.56 and 3.36 kg/ha; the higher rate is commonly used for control of weeds in rice. ‘Davis’, ‘Hood’, and ‘York’ soybean cultivars were damaged more by propanil than ‘Hill’, ‘Lee’, ‘Lee 68’, ‘Pickett’, ‘Semmes’, ‘Bragg’, or ‘Dare’ when damage was measured by reductions in seed yield and stand and by leaf injury.


Plant Disease ◽  
2006 ◽  
Vol 90 (5) ◽  
pp. 597-602 ◽  
Author(s):  
M. T. Kirkpatrick ◽  
C. S. Rothrock ◽  
J. C. Rupe ◽  
E. E. Gbur

The effect of flooding and Pythium ultimum on soybean, Glycine max, was determined in a series of greenhouse experiments using the cultivars Hutcheson and Archer. Seeds were planted into pasteurized soil either not infested or infested with sand-cornmeal inoculum of P. ultimum and either flooded at emergence for 2 days or at the four leaf node stage (V4) for 5 days. A nonflooded control was included in each experiment. Seeds placed directly into infested soil resulted in little or no stand for Hutcheson regardless of flood treatment, whereas stand was reduced for Archer only in the flooded infested soil treatment. Additional experiments were conducted by placing seed onto a 2- to 5-mm layer of pathogen-free soil on top of the infested soil. Flooding at emergence reduced plant height, growth stage, and top dry weight for Hutcheson and root fresh weight for both cultivars. Greater reductions for Hutcheson in root weight, and top dry weight in P. ultimum-infested soil in the soil layer experiments, also indicated that Hutcheson was more susceptible than Archer. Flooding alone decreased root weights, and infestation with P. ultimum reduced weights further resulting in an additive effect. This also was the case for plant height, growth stage, and top dry weight for Hutcheson for flooding at emergence. Root discoloration was greatly increased for both cultivars in infested soil flooded at emergence. Similar results were found when plants were flooded at V4; however, the effect was not as great as with flooding at emergence. These studies indicate that Pythium damping-off and root rot may account for a portion of the negative response of soybean to flooding. The results also indicate that Archer has some resistance to P. ultimum.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Michele Pittol ◽  
Erin Scully ◽  
Daniel Miller ◽  
Lisa Durso ◽  
Lidia Mariana Fiuza ◽  
...  

In agricultural systems, interactions between plants and microorganisms are important to maintaining production and profitability. In this study, bacterial communities in floodwaters of rice fields were monitored during the vegetative and reproductive stages of rice plant development using 16S amplicon sequencing. The study was conducted in the south of Brazil, during the crop years 2011/12 and 2012/13. Comparative analyses showed strong differences between the communities of floodwaters associated with the two developmental stages. During the vegetative stage, 1551 operational taxonomic units (OTUs) were detected, while less than half that number (603) were identified in the reproductive stage. The higher bacterial richness observed in floodwater collected during the vegetative stage may have been favored by the higher concentration of nutrients, such as potassium, due to rhizodeposition and fertilizer application. Eighteen bacterial phyla were identified in both samples. Both communities were dominated by Gammaproteobacteria. In the vegetative stage, Alphaproteobacteria and Betaproteobacteria were more abundant and, in contrast, Bacilli and Clostridia were the more dominant classes in the reproductive stage. The major bacterial taxa identified have been previously identified as important colonizers of rice fields. The richness and composition of bacterial communities over cultivation time may contribute to the sustainability of the crop.


2019 ◽  
Vol 37 ◽  
Author(s):  
L.B.P. BRAZ ◽  
G.B.P. BRAZ ◽  
S.O. PROCÓPIO ◽  
C.J.B. FERREIRA ◽  
A.G. SILVA ◽  
...  

ABSTRACT: The presence of volunteer corn plants in coexistence with soybean has been increasing since the introduction of glyphosate-resistant corn hybrids. This study aimed to evaluate the effect of interference of volunteer RR® corn plants at different densities on two RR® soybean cultivars. The experiment was conducted in Rio Verde, GO. The experimental design was a randomized block design in a factorial arrangement (2×5), with four replications. Factor A consisted of two soybean cultivars (BMX Potência RR® and M8210 IPRO®), while five densities of RR® corn plants per m2 (0, 4, 8, 12, and 16) were adopted for factor B. The following evaluations were carried out for soybean: plant height, SPAD index, percentage of interrow closure, shoot dry matter, first pod height, number of pods per plant, 100 grain weight, and grain yield of grains. Soybean plant height presented a linear and positive relationship with the increased density of corn plants. Shoot dry matter, 100 grain weight, number of pods per plant, and grain yield were negatively affected by the increased density of volunteer corn infestation. The soybean cultivar M8210 IPRO® was more susceptible to corn plant interference when compared to the cultivar BMX Potência RR®.


2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4151
Author(s):  
Giovani Facco ◽  
Alberto Cargnelutti Filho ◽  
Alessandro Dal’Col Lúcio ◽  
Gustavo Oliveira dos Santos ◽  
Réges Bellé Stefanello ◽  
...  

The objectives of this study were to determine the sample size (i.e., number of plants) required to accurately estimate the average of morphological traits of pigeonpea (Cajanus cajan L.) and to check for variability in sample size between evaluation periods and seasons. Two uniformity trials (i.e., experiments without treatment) were conducted for two growing seasons. In the first season (2011/2012), the seeds were sown by broadcast seeding, and in the second season (2012/2013), the seeds were sown in rows spaced 0.50 m apart. The ground area in each experiment was 1,848 m2, and 360 plants were marked in the central area, in a 2 m × 2 m grid. Three morphological traits (e.g., number of nodes, plant height and stem diameter) were evaluated 13 times during the first season and 22 times in the second season. Measurements for all three morphological traits were normally distributed and confirmed through the Kolmogorov-Smirnov test. Randomness was confirmed using the Run Test, and the descriptive statistics were calculated. For each trait, the sample size (n) was calculated for the semiamplitudes of the confidence interval (i.e., estimation error) equal to 2, 4, 6, ..., 20% of the estimated mean with a confidence coefficient (1-?) of 95%. Subsequently, n was fixed at 360 plants, and the estimation error of the estimated percentage of the average for each trait was calculated. Variability of the sample size for the pigeonpea culture was observed between the morphological traits evaluated, among the evaluation periods and between seasons. Therefore, to assess with an accuracy of 6% of the estimated average, at least 136 plants must be evaluated throughout the pigeonpea crop cycle to determine the sample size for the traits (e.g., number of nodes, plant height and stem diameter) in the different evaluation periods and between seasons.


Author(s):  
Ramazan İlhan Aytekin ◽  
Sevgi Çalışkan

Uniform description of developmental stages in crops improve communication among producers, researchers and others. A standardized, accurate, and easy system is needed to describe bean (Phaseolus vulgaris L.) plant development. The objective of this study was to develop and describe stages of bean plant development in a manner which is simple but accurate. The biological cycle of the bean plant is divided into two successive phases: the vegetative stage (V) and the reproductive stage (R). Vegetative stages are determined by counting the number of trifoliolate leaves (V1 to VN) on the main stem beginning above the unifoliate leaf. Reproductive stages R1 and R2 are based on flowering, R3 and R4 on pod development, R5 and R6 on seed development, and R7, R8 and R9 on maturation.


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