scholarly journals Analysis of cassava growth at different harvest times and planting densities

2019 ◽  
Vol 40 (1) ◽  
pp. 113
Author(s):  
Eli Carlos de Oliveira ◽  
Luiz Henrique Campos de Almeida ◽  
Claudemir Zucareli ◽  
Teresa Losada Valle ◽  
José Roberto Pinto de Souza ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Mass ◽  
Area Ratio ◽  
Plant Population ◽  
Leaf Area Ratio ◽  
Primary Data ◽  
Population Densities ◽  
Relative Growth

Vegetative canopy architecture, and plant population density, has a direct influence on the growth and production of crops. The objective of this study was to evaluate the growth of four cassava cultivars of contrasting canopies, in four population densities, during two vegetative cycles. A randomized complete block design was used in a subdivided plot scheme, with two replications, with the population densities in the plots and harvesting times in the subplots. ‘Branca de Santa Catarina’ (BSC), ‘IAC 13’, ‘IAC 14-18’ and ‘Fibra’ were collected every four months, beginning at 120 and ending at 720 days after planting (DAP). Primary data on dry matter and leaf area were calculated. The total dry mass (Wt), leaf area ratio (La), leaf area index (L), relative growth rate (Rw), and net assimilation rate (Ea) were calculated based on the primary data. All cultivars accumulated more total dry mass (Wt) at lower planting densities. The plants reached a higher leaf area ratio (La) 120 days after planting. In the second vegetative cycle, the four cultivars, independently of the population, presented a reduction of assimilate translocation to the leaves. Relative growth rate (Rw) of the cultivars varied strongly with the plant population only in the second cycle. ‘IAC 14-18’ showed greater dependence on spacing, and ‘Fibra’ less dependence. Growth (Rw) and assimilatory (Ea) rates decreased at the end of the first cycle, then increased slowly until the end of the second cycle of vegetation.

scholarly journals Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

2012 ◽  
Vol 30 (2) ◽  
pp. 317-325 ◽  
Author(s):  
R.C. Souza ◽  
A.C. Dias ◽  
M.R.A. Figueiredo ◽  
F.E.B. Obara ◽  
P.J Christoffoleti
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Area Ratio ◽  
Leaf Area Ratio ◽  
Leaf Number ◽  
Relative Growth ◽  
Absolute Growth Rate ◽  
Absolute Growth

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

scholarly journals The Contribution by Leaves of Different Age to New Growth of Subterranean Clover Plants Following the Removal of a Sulphur Stress I. Origin and Distribution of Dry Matter

1972 ◽  
Vol 25 (6) ◽  
pp. 1147 ◽  
Author(s):  
D Bouma ◽  
EAN Greenwood ◽  
EJ Dowling
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Area Ratio ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Net Assimilation ◽  
Nutrient Solutions

During the first 3 days after transfer of moderately sulphur-deficient plants (S1) to full nutrient solutions, the relative growth rate (Rw) was considerably lower than that of plants raised at higher sulphur levels (S2 and Sa). This was reflected in a lower leaf area ratio of the S1 plants, and particularly in a reduction of nearly 50% in the net assimilation rate (EA). Net losses in dry matter from younger emerged leaves and petioles accounted for 25% of the dry matter in new leaves and petioles of S1 plants produced during this period.

scholarly journals Evaluación de respuestas fisiológicas de la planta arbórea Hibiscus rosasinensis L, (Cayeno) en condiciones de campo y vivero

2010 ◽  
Vol 11 (1) ◽  
pp. 61 ◽  
Author(s):  
Nestor Dario Cuéllar ◽  
Juan Manuel Arrieta Herrera
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Area Ratio ◽  
Net Assimilation Rate ◽  
Silvopastoral Systems ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Hibiscus Rosa Sinensis ◽  
Net Assimilation

<p>Con la finalidad de conocer y entender las características fisiológicas y productivas de especies forrajeras con una alta potencialidad para ser involucradas dentro de los sistemas silvo-pastoriles, se llevó a cabo el presente estudio sobre Hibiscus rosa-sinensis. Las plantas se ubicaron bajo condiciones de vivero (17°C) y siembra directa en campo (22°C), en la estación experimental La Esperanza, localizada en el municipio de Fusagasugá (Cundinamarca, Colombia) a 4°16´34´´ N y 23´11´´ W, 1750 msnm, 20°C de temperatura promedio, 1200 mm./año, el 81% de humedad relativa y 1387 horas de luz/año. Los muestreos se realizaron cada ocho (8) días y se evaluaron los estados de crecimiento y desarrollo de la especie forrajera Hibiscus y el modelo de distribución radicular. Cuando la planta de Hibiscus rosa-sinensis se desarrolla bajo condiciones de vivero se genera un modelo de raíz gravitrópico, fuerte, con dos raíces principales pivotantes, con abundantes y extensas raíces laterales primarias y secundarias (Modelo Tsutsumi et al, 2003); por el contrario, en campo el modelo predice que las plantas desarrollan un modelo radicular plagio-gravitrópico superficial; a los 105 días la relación raíz:brote (R:B) es muy deficiente (0,16), frente a las de vivero (0,25). Las dos (2) raíces principales y las laterales primarias y secundarias no son muy abundantes. Hasta los 105 días después de la siembra, las plantas bajo las condiciones de vivero son superiores a las establecidas en siembra directa en su índice de área foliar (IAF), área foliar efectiva (AFE), tasa de asimilación neta (TAN) y, por consiguiente, en su tasa de crecimiento relativo (TCR); a partir de este tiempo, las plantas en campo comienzan una fase de crecimiento exponencial, como lo mostró la TCR y la TAN. La especie Hibiscus rosa-sinensis necesariamente requiere una fase de vivero de hasta los 98 o 105 días. El sistema de raíz desarrollado por la planta permite conocer que la fertilización temprana no sería viable y que ésta se puede realizar a partir de los 60 días después del transplante, cuando el desarrollo alométrico de la planta es equilibrado. Las tasas e índices fisiológicos (TAN, RAF, AFE, IAF, TCR) nos permiten proponer la especie Hibiscus rosa-sinensis como una planta óptima para los sistemas de silvopastoreo y planificar las labores culturales y agronómicas como especie forrajera.</p><p> </p><p><strong>Evaluating Physiological Responses to Hibiscus rosa-sinensis L. under Conditions of Direct Planting and Nursery</strong></p><p>Aiming to know and understanding the physiological and productive forages species traits potentially to get involved into silvopastoral systems, this experiment were conducted at nurserys (17°C) and direct sown (22°C) conditions. The experimental station “La Esperanza” is in Fusagasugá, Colombia at 4°16´34´´N and 23´11´´´W, 1750 masl, 20°C average temperature, 1200 mm/year, 81% RH, 1387 light hour/year. The sampling were realized each eight (8) days and assessing variability in growth, cumulative leaf area, aboveground biomass, mean relative growth rate, mean net assimilation rate, and mean leaf area ratio related to forages specie Hibiscus rosa-sinensis L. Moreover were evaluated a distribution roots model. Plant species widely differ in their grown potential when they are grown under different conditions. The results shown that H. rosa-sinensis rising in nursery conditions had a more elongated, greater radial growth and gravitrópic roots than those of direct planting plants. The ratio between roots and shoot is strongly and positive related to the nursery (0.75) and poor in direct sown (0.16) conditions during 105 days after planting (dap). Also another factor as physiology (the net assimilation rate, specific leaf area, leaf area ratio) can explain the difference in RGR (relative growth rate) between species grown in nursery and direct planting conditions. At this stage (105 days) the plants shown the highest values on relative growth and net assimilation rate in nursery conditions. Furthermore the Hibiscus rosa-sinensis specie require grown in a nursery phase until 98 days to optimum conditions to planting in open fields. Fees and physiological indices (TAN, RAF, SLA, LAI, RGR) allow us to propose the species Hibiscus rosa-sinensis as an optimal plant silvopastoral systems and cultural planning and agricultural work as a forage.</p>

scholarly journals Seed mass effects on germination and growth of diverse European Scots pine populations

1994 ◽  
Vol 24 (2) ◽  
pp. 306-320 ◽  
Author(s):  
P.B. Reich ◽  
J. Oleksyn ◽  
M.G. Tjoelker
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Scots Pine ◽  
Field Experiments ◽  
Seed Mass ◽  
Growing Season ◽  
Turkish Population ◽  
Dry Mass ◽  
Relative Growth ◽  
Mass Effects

Seedlings of 24 European Scots pine (Pinussylvestris L.) populations were grown in controlled environment chambers under simulated photoperiodic conditions of 50 and 60°N latitude to evaluate the effect of seed mass on germination and seedling growth characteristics. Seeds of each population were classified into 1-mg mass classes, and the four classes per population with the highest frequencies were used. Photoperiod had minimal influence on seed mass effects. Overall, seed mass was positively related to the number of cotyledons and hypocotyl height. Populations differed significantly in seed mass effect on biomass. In northern populations (55–61°N), dry mass at the end of the first growing season was little affected by seed mass. However, dry mass in 9 of 15 central populations (54–48°N) and all southern (<45°N) populations correlated positively with seed mass. Relative growth rate was not related to seed mass within or across populations, and thus early growth is largely determined by seed mass. Relative growth rate also did not differ among populations, except for a geographically isolated Turkish population with the highest seed mass and lowest relative growth rate. After one growing season, height was positively correlated (r2 > 0.6) with seed mass in 15 populations. To check the duration of seed mass effects, height growth of 1- to 7-year-old field experiments established with the same seed lots were compared. Seed mass effects on height were strongest for 1-year-old seedlings and declined or disappeared by the age of 5–7 years among central and southern populations, but remained stable over that time in northern populations.

Low temperature effects on the growth of evening primrose (Oenothera spp.) rosettes

2004 ◽  
Vol 52 (1) ◽  
pp. 19-28
Author(s):  
A. F. Fieldsend
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Relative Rate ◽  
Field Trials ◽  
Effect Of Temperature ◽  
Relative Growth ◽  
Evening Primrose ◽  
Intermittent Exposure ◽  
Environment Experiment

In field crops of evening primrose (Oenothera spp.) the post-winter growth of rosettes is slow to re-start. The effect of temperature on the growth of rosettes was assessed in a controlled environment experiment. Relative growth rate was positively correlated with temperature, but in apparent contrast to the results from field trials, the rosettes grew at constant temperatures as low as 6.5ºC. However, following transfer to warmer temperatures an increase in relative growth rate did not occur until 7-10 days later, whilst a change to a cooler environment caused an immediate reduction in relative growth rate. Thus, it seems likely that growth is inhibited by intermittent exposure to temperatures of 0°C or below. Partitioning of biomass between root and shoot was independent of temperature, but at 6.5ºC the relative rate of leaf area increase was very low. Consequently, the specific leaf area was lower in rosettes growing at lower temperatures.

scholarly journals Growth Analysis of Wheat Using Machine Vision: Opportunities and Challenges

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6501
Author(s):  
Mohammad Ajlouni ◽  
Audrey Kruse ◽  
Jorge A. Condori-Apfata ◽  
Maria Valderrama Valencia ◽  
Chris Hoagland ◽  
...  
Keyword(s):  
Growth Rate ◽  
Machine Vision ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Growth Analysis ◽  
Growth Parameters ◽  
Dry Weight ◽  
Projected Area ◽  
Relative Growth ◽  
Leaf Dry Weight

Crop growth analysis is used for the assessment of crop yield potential and stress tolerance. Capturing continuous plant growth has been a goal since the early 20th century; however, this requires a large number of replicates and multiple destructive measurements. The use of machine vision techniques holds promise as a fast, reliable, and non-destructive method to analyze crop growth based on surrogates for plant traits and growth parameters. We used machine vision to infer plant size along with destructive measurements at multiple time points to analyze growth parameters of spring wheat genotypes. We measured side-projected area by machine vision and RGB imaging. Three traits, i.e., biomass (BIO), leaf dry weight (LDW), and leaf area (LA), were measured using low-throughput techniques. However, RGB imaging was used to produce side projected area (SPA) as the high throughput trait. Significant effects of time point and genotype on BIO, LDW, LA, and SPA were observed. SPA was a robust predictor of leaf area, leaf dry weight, and biomass. Relative growth rate estimated using SPA was a robust predictor of the relative growth rate measured using biomass and leaf dry weight. Large numbers of entries can be assessed by this method for genetic mapping projects to produce a continuous growth curve with fewer replicates.

Phenyl indole-3-thiolobutyrate increases growth of transplanted 1-0 red oak

1988 ◽  
Vol 18 (1) ◽  
pp. 131-134
Author(s):  
Daniel K. Struve ◽  
W. Timothy Rhodus
Keyword(s):  
Leaf Area ◽  
Butyric Acid ◽  
Dry Weight ◽  
Area Ratio ◽  
Leaf Area Ratio ◽  
Red Oak ◽  
Relative Growth ◽  
Auxin Treatment ◽  
Net Assimilation

The basal 1 cm of taproot of dormant bareroot 1-0 red oak (Quercusrubra L.) seedlings were given a 3-s dip in 20, 40, or 80 mM concentrations of indole-3-butyric acid (IBA), phenyl indole-3-thiolobutyrate (P-ITB), or equal parts IBA and P-ITB at 20 or 40 mM concentrations. Sixty control seedlings were dipped in 95% ethanol, while 30 seedlings were used for each auxin treatment. Seedlings were potted on May 12, 1986, and grown outdoors. At the end of the 104-day study period, all concentrations of IBA and P-ITB significantly increased number of roots regenerated (from 5.3 with 20 mM IBA to 11.9 for 80 mM IBA) compared with control seedlings. However, P-ITB-treated seedlings produced significantly more leaves (20–24) and leaf area (320–472 cm2), and up to 10 g more dry weight than IBA and non-auxin-treated seedlings. P-ITB treated seedlings had higher relative growth and net assimilation rates and lower leaf area ratio than IBA-treated or control seedlings. Seedlings treated with 20 mM of equal parts IBA and P-ITB were similar to P-ITB-treated seedlings while seedlings treated with the 40 mM IBA and P-ITB combination were similar to IBA-treated seedlings.

scholarly journals Fitness Cost of Imazamox Resistance in Wild Poinsettia (Euphorbia heterophylla L.)

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1859
Author(s):  
Saeid Hassanpour-bourkheili ◽  
Mahtab Heravi ◽  
Javid Gherekhloo ◽  
Ricardo Alcántara-de la Cruz ◽  
Rafael De Prado
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Dry Weight ◽  
Area Ratio ◽  
Fitness Cost ◽  
Seed Plant ◽  
Growth Indices ◽  
Relative Growth ◽  
Net Assimilation

Wild poinsettia (Euphorbia heterophylla L.) is a difficult-to-control weed in soybean production in Brazil that has developed resistance to herbicides, including acetolactate synthase inhibitors. We investigated the potential fitness cost associated to the Ser-653-Asn mutation that confers imazamox resistance in this weed. Plant height, leaf and stem dry weight, leaf area and seed production per plant as well as the growth indices of specific leaf area, leaf area ratio, relative growth rate and net assimilation in F2 homozygous resistant (R) and susceptible (S) wild poinsettia progenies were pairwise compared. S plants were superior in most of the traits studied. Plant heights for S and R biotypes, recorded at 95 days after planting (DAP), were 137 and 120 cm, respectively. Leaf areas were 742 and 1048 cm2 in the R and S biotypes, respectively. The dry weights of leaves and stems in the S plants were 30 and 35%, respectively, higher than in the R plants. In both biotypes, the leaves had a greater share in dry weight at early development stages, but from 50 DAP, the stem became the main contributor to the dry weight of the shoots. The R biotype produced 110 ± 4 seed plant−1, i.e., 12 ± 3% less seeds per plant than that of the S one (125 ± 7 seed plant−1). The growth indices leaf area ratio and specific leaf area were generally higher in the S biotype or similar between both biotypes; while the relative growth rate and net assimilation rate were punctually superior in the R biotype. These results demonstrate that the Ser-653-Asn mutation imposed a fitness cost in imazamox R wild poinsettia.

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