scholarly journals Seeding date, photoperiod and nitrogen effects on specific leaf area of field-grown wheat

1998 ◽  
Vol 78 (1) ◽  
pp. 51-61 ◽  
Author(s):  
G. K. Hotsonyame ◽  
L. A. Hunt
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Simulation Models ◽  
Sowing Date ◽  
Field Conditions ◽  
Leaf Position ◽  
Leaf Production ◽  
Individual Leaf ◽  
Sowing Dates ◽  
The Impact

Specific leaf area (SLA), the ratio of leaf area to leaf weight, is an important plant characteristic that affects the rate of dry matter production of crop canopies. It is affected by the conditions of growth of both isolated plants and crop communities, but the extent to which various environmental factors impact on SLA under field conditions is not clearly understood. This study was conducted to study the variability in SLA of leaves on the main culm, and in the leaf canopy as an entity, under different conditions of photoperiod, nitrogen and temperature for a number of wheat genotypes grown under field conditions. Five plantings at approximately bimonthly intervals on 12 May, 5 July and 22 September 1993; and on 9 June and 10 August 1994 were made under both natural photoperiod and an extended photoperiod of 20 h. A split plot design with two levels of nitrogen (0 kg N ha−1 and 150 kg N ha−1) as main plots and four genotypes of wheat comprising two spring types (Norseman and Roblin) and two winter types (Ruby and Harus) as subplots was used.SLA of individual leaves varied among leaf positions, but the pattern of variation was dependent on sowing date and genotype. For May and June sowing dates, SLA increased with leaf number up to leaf 5 and then declined with subsequent leaf numbers for the spring genotypes, but increased to leaf 5 and changed little thereafter for the winter types. For July or August sowing and for both spring and winter genotypes, the change in SLA with leaf position was less clear. The results further showed that some of this variability in SLA with leaf position could be accounted for by the mean air temperatures over which the leaves developed. As temperatures increased from 8 °C to 26 °C, SLA increased to a maximum value achieved at 18–20 °C and then declined. However, there was a large scatter of SLA values around 18–20 °C, due partly to some lower SLA values for the July and August sowing dates. This suggests the impact of other factors such as radiation and the degree of mutual shading within the canopy on SLA. Mean canopy SLA reflected the individual leaf values during the period of leaf production, and varied with sowing date and genotype, although the pattern of genotypic variability was inconsistent over sowing dates; it decreased rapidly after spike emergence presumably reflecting leaf aging. Neither nitrogen nor photoperiod had significant effects on SLA on both individual leaf and canopy bases.The results suggest that temperature is one factor affecting SLA under field conditions, but that further work to identify other factors impacting on SLA in the field will be necessary. For application of simulation models to situations in which temperatures are likely to vary, an accounting for the impact of temperature on the SLA of individual leaves would be desirable. Key words: Specific leaf area (SLA), sowing date, temperature, simulation, wheat

scholarly journals Estimation of buckwheat leaf area by leaf dimensions

2021 ◽  
Vol 42 (3Supl1) ◽  
pp. 1529-1548
Author(s):  
Alberto Cargnelutti Filho ◽  
◽  
Rafael Vieira Pezzini ◽  
Ismael Mario Márcio Neu ◽  
Gabriel Elias Dumke ◽  
...  
Keyword(s):  
Leaf Area ◽  
Linear Model ◽  
Leaf Blade ◽  
Sowing Date ◽  
Quadratic Model ◽  
Digital Photo ◽  
Sowing Dates ◽  
Leaf Dimensions ◽  
Fagopyrum Esculentum Moench ◽  
Uniformity Trials

The objective of this work was to model and identify the best models for estimating the leaf area, determined by digital photos, of buckwheat (Fagopyrum esculentum Moench) of the cultivars IPR91-Baili and IPR92-Altar, as a function of length (L), width (W) or length x width product (LW) of the leaf blade. Ten uniformity trials (blank experiments) were carried out, five with IPR91-Baili cultivar and five with IPR92-Altar cultivar. The trials were performed on five sowing dates. In each trial and cultivar, expanded leaves were collected at random from the lower, middle and upper segments of the plants, totaling 1,815 leaves. In these 1,815 leaves, L and W were measured and the LW of the leaf blade was calculated, which were used as independent variables in the model. The leaf area of each leaf was determined using the digital photo method (Y), which was used as a dependent variable of the model. For each sowing date, cultivar and thirds of the plant, 80% of the leaves (1,452 leaves) were randomly separated for the generation of the models and 20% of the leaves (363 leaves) for the validation of the models of leaf area estimation as a function of linear dimensions. For buckwheat, IPR91-Baili and IPR92-Altar cultivars, the quadratic model (Ŷ = 0.5217 + 0.6581LW + 0.0004LW2, R2 = 0.9590), power model (Ŷ = 0.6809LW1.0037, R2 = 0.9587), linear model (Ŷ = 0.0653 + 0.6892LW, R2 = 0.9587) and linear model without intercept (Ŷ = 0.6907LW, R2 = 0.9587) are indicated for the estimation of leaf area determined by digital photos (Y) based on the LW of the leaf blade (x), and, preferably, the linear model without intercept can be used, due to its greater simplicity.

scholarly journals Influence of High Tunnel and Field Conditions on Strawberry Growth and Development

HortScience ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 329-335 ◽  
Author(s):  
Sorkel Kadir ◽  
Edward Carey ◽  
Said Ennahli
Keyword(s):  
Leaf Area ◽  
Fruit Quality ◽  
Growth Yield ◽  
Fruit Production ◽  
Field Conditions ◽  
Soluble Solids ◽  
Shoot Biomass ◽  
Leaf Production ◽  
High Tunnel ◽  
Solids Concentration

Plant growth, yield, and fruit quality of two strawberries (Fragaria ×ananassa Duch.)—`Chandler' and `Sweet Charlie'—grown under high tunnels (HTs) were compared with that of field plants during 2002–03 and 2003–04 growing seasons. Plug plants were planted in mid-October 2002 and mid-September 2003 on raised beds covered with black polyethylene mulch. Microclimate of the HTs protected strawberry crowns from winter damage and advanced fruit production 5 weeks earlier than that of plants grown under field conditions. From December to February, average minimum and maximum crown temperatures under the HTs were 5 and 12 °C warmer than those of the field crowns, respectively. The earliest HT fruit were harvested on 7 Apr. 2003 and 11 Mar. 2004. Yield and fruit quality under the HTs were superior to that of field-grown plants. HT plants, especially `Sweet Charlie', bloomed earlier than did field plants, but `Chandler' produced higher yield than `Sweet Charlie' late in the season. Larger fruit with higher soluble solids concentration (SSC) were produced inside the HTs than outside. HT `Sweet Charlie' fruit were sweeter than `Chandler' fruit, but `Chandler' produced larger fruit. Larger leaf area, greater number of leaves and shoot biomass, more branch-crowns, and fewer runners were developed under HTs than field conditions. Total leaf area, leaf production, total shoot biomass, and number of branch-crowns of HT `Chandler' were greater than HT `Sweet Charlie'. Results of this study indicate that strawberry plants under HTs were not only precocious, but also produced higher yields and superior quality to that of field plants. HT conditions suppressed runner growth, but enhanced branch-crown development.

scholarly journals THE IMPACT OF LIGHT PENETRATION INTO CANOPY AND SEASONALITY ON PHOTOSYNTHETIC INDICES IN APPLE TREE LEAVES

AGROFOR ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Giedrė SAMUOLIENĖ ◽  
Kristina LAUŽIKĖ ◽  
Nobertas USELIS
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Apple Tree ◽  
Weight Ratio ◽  
Dry Weight ◽  
Light Penetration ◽  
Fresh Weight ◽  
Photochemical Reflectance Index ◽  
Plant Senescence ◽  
The Impact

The aim of this study was to analyse the impact of light penetration into canopy and the effect of distances between technological tools and seasonality on photosynthetic behaviour. Apple tree cultivar ‘Auksis’ was grafted onto superdwarfing rootstock P22 and planted at different distances (from 0,25 m to 1 m in rows, while space between rows was 3 m). Photochemical reflectance and plant senescence reflectance indices were measured at two heights: 1.0 – 1.2 m above ground and 1.8 – 2.0 m above ground; specific leaf area, fresh and dry weight were evaluated from all the canopy. Strong positive correlations were determined between photochemical reflectance index and plant senescence reflectance index in higher and lower levels of the canopy. Strong negative correlations were determined between photochemical reflectance index and plant senescence reflectance index and between specific leaf area and dry and fresh mass ratio. Increasing density between apple trees from 1 m to 0.5 m led to increase in photochemical reflectance index and specific leaf area, but plant senescence reflectance index decreased. Meanwhile, seasonality had significant impact on specific leaf area formation and dry to fresh weight ratio. Dry and fresh weight ratio increased by 5% in autumn compared to summer. Our results indicated that with decreased light penetration into canopy photochemical reflectance index decreased, but plant senescence reflectance index increased. Moreover, in autumn, trees prepare for winter by storing more nutrients and leaves accumulate more dry mass.

Evaluating the Impact of a Trait for Increased Specific Leaf Area on Wheat Yields Using a Crop Simulation Model

2003 ◽  
Vol 95 (1) ◽  
pp. 10 ◽  
Author(s):  
Senthold Asseng ◽  
Neil C. Turner ◽  
Tina Botwright ◽  
Anthony G. Condon
Keyword(s):  
Simulation Model ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Crop Simulation Model ◽  
Crop Simulation ◽  
The Impact

Effects of sowing date, sowing density and nitrogen supply on leaf extension in spring barley

1989 ◽  
Vol 113 (3) ◽  
pp. 305-315 ◽  
Author(s):  
A. A. S. Maan ◽  
D. Wright ◽  
M. B. Alcock
Keyword(s):  
Leaf Area ◽  
Sowing Date ◽  
Nitrogen Supply ◽  
Extension Growth ◽  
Thermal Time ◽  
Extension Rate ◽  
Leaf Position ◽  
Main Shoot ◽  
N Supply ◽  
Leaf Extension

SUMMARYThree pot experiments were performed in unheated glasshouses at the University College of North Wales College Farm, Aber, Gwynedd in 1980–1983. Two experiments tested the effects of sowing date and N supply, the third sowing density and nitrogen supply. Extension growth of main-stem leaves was measured by ruler and expressed in thermal time units to allow comparisons between sowing dates. Rate and duration of leaf extension were determined from linear regressions of leaf length against thermal time.Increasing N supply increased leaf extension rate but had no significant effects on leaf extension duration. Leaf extension rate increased with leaf position on the main shoot, but decreased slightly in leaves extending at the time of stem elongation. Leaf extension duration also increased with leaf position on the main shoot and was related to mean temperature during the leaf extension phase. Plants sown in September were able to compensate for lower radiation receipts by having a faster rate and longer duration of leaf extension, by producing larger leaves with a greater specific lamina area and by partitioning a greater proportion of extension growth into lamina and less into sheaths. In plants sown in June, the largest leaf occurred at a lower stem node and leaves emerging later showed a strong response to N. It is suggested that this is attributable to earlier onset of internal competition for assimilates. Variation in leaf extension rate was the main factor influencing variation in final leaf area. There was a strong positive relationship between leaf extension rate and leaf N content.Increasing sowing density increased the area of the first four leaves on the main shoot and decreased that of later leaves, changes mainly associated with changes in leaf extension duration. It is concluded that progress in the modelling of leaf area expansion, light interception and dry matter production requires more information about how sowing date, sowing density and N supply interact to influence crop development and leaf growth.

scholarly journals Influence of sowing dates on stemphylium blight disease severity and yield performance of lentil at Rampur, Chitwan, Nepal

2018 ◽  
pp. 129-136 ◽  
Author(s):  
S. Subedi ◽  
S. M. Shrestha ◽  
G. B. Khatri-Chhetri ◽  
R. B. Thapa ◽  
S. K. Ghimire ◽  
...  
Keyword(s):  
Disease Severity ◽  
Lens Culinaris ◽  
Sowing Date ◽  
Field Conditions ◽  
Disease Development ◽  
Yield Performance ◽  
Sowing Dates ◽  
Stemphylium Blight ◽  
Blight Disease ◽  
Year 2013

A study on lentil (Lens culinaris Medik) was carried out at Rampur, Chitwan with different sowing dates under field conditions to assess the severity of Stemphylium blight disease severity and yield performance during two consecutive years 2012-2014. During 2012/013, lower (3.00) and higher disease severity (6.50) were recorded on lentil plants sown on November 6 and December 16, respectively. Early sown lentil resulted in higher yield (2025 kg/ha) followed by late shown one (1213 kg/ha). Similarly, trends of disease development were similar in succeeding year (2013/14). Lentil seed shown on November 1 had lower disease severity (3.50) and produced higher yield (962.50 kg/ha) compared to that were shown on later dates. Disease severity increased with the advancement of sowing date from November 1 to December 21 with decreased yields. Hence, over years, early shown lentil (November 1, 6 and 11) escaped the higher severity of Stemphylium blight with the increase in yield.Journal of the Institute of Agriculture and Animal Science.Vol. 33-34, 2015, Page: 129-136

Final grain weight in wheat as affected by short periods of high temperature during pre- and post-anthesis under field conditions

1999 ◽  
Vol 26 (5) ◽  
pp. 453 ◽  
Author(s):  
Roxana Savin ◽  
Daniel F. Calderini ◽  
Gustavo A. Slafer ◽  
Leonor G. Abeledo
Keyword(s):  
High Temperature ◽  
Grain Filling ◽  
Sowing Date ◽  
Temperature Treatment ◽  
Grain Weight ◽  
Field Conditions ◽  
High Temperature Treatment ◽  
Sowing Dates ◽  
Grain Filling Period ◽  
Response To Temperature

Individual grain weight is an important source of variation for grain yield in wheat. The aim of this study was to investigate the effect of short periods of high temperature immediately pre-anthesis, or during post-anthesis, on grain weight under field conditions. Thus, two wheat cultivars of different grain weight potential were sown on four different sowing dates to provide different temperature conditions during the pre- and post-anthesis periods. In addition, for two sowings, acrylic boxes were installed to increase spike temperature either immediately before anthesis, or during the lineal phase of the grain-filling period. Final grain weight was significantly affected by sowing date, genotype and grain position on the spike. Grain weight showed a clear relationship with the average temperature of the grain filling period, but this relationship was either linear or curvilinear, depending on the cultivar. Both high temperature treatments, i.e. at pre- or post-anthesis, significantly diminished final grain weight, and their effect was similar with the exception of heavier grains, which were unresponsive to the high temperature treatment at pre-anthesis. Finally, a better understanding of final grain weight was reached when temperatures from the pre-anthesis period were included in the analysis of grain weight response to temperature.

scholarly journals Growth attributes of rapeseed varieties (Brassica campestris l.) in relation to sowing dates and weedings treatments

2015 ◽  
Vol 21 ◽  
pp. 51-59
Author(s):  
Mst Towhida Akhter ◽  
PB Kundu ◽  
NK Paul
Keyword(s):  
Leaf Area ◽  
Brassica Campestris ◽  
Sowing Date ◽  
Area Index ◽  
Crop Growth Rate ◽  
Sowing Dates ◽  
Growth Attributes ◽  
Net Assimilation ◽  
Hand Weeding ◽  
Plot Design

Context: To analyze the effect of sowing dates and weeding treatments on growth attributes such as total dry matter (TDM), leaf area index (LAI), net assimilation rate (NAR), crop growth rate (CGR), leaf area ratio (LAR) of three rapeseed (Brassica campestris L.) Objectives: The objective of the study was to identify the growth in relation to sowing dates and weed competition and identify the weeding number for better growth of rapeseed. Materials and Methods: This investigation was arranged as factorial experiment based on the split-split plot design with three replications. Four sowing dates were including 18 October (S1), 12 November (S2), 17 November (S3) and 3 December (S4) and three weeding treatments were no weeding (W0), one hand weeding (W1) and two hand weeding (W2) and three varieties viz., BINA Sarisha-5, BINA Sarisha-6 and BARI Sarisha-14 were investigated. Results: The results showed that, TDM, LAI, CGR, NAR and LAR were affected by sowing date and weeding treatments. The highest TDM, LAI and CGR were obtained in the first sowing and two weedings treatment. The highest NAR was found in S2 plants and W0 treatment. The highest LAR was found in S2 plants and W1 treatment. Conclusion: The results obtained in this study suggest that the first sowing and two weeding treatments are superior for the production of rapeseed. DOI: http://dx.doi.org/10.3329/jbs.v21i0.22519 J. bio-sci. 21: 51-59, 2013

scholarly journals Leaf Area Estimation in Chamomile

2019 ◽  
Vol 11 (2) ◽  
pp. 429
Author(s):  
Jocélia Rosa da Silva ◽  
Arno Bernardo Heldwein ◽  
Andressa Janaína Puhl ◽  
Adriana Almeida do Amarante ◽  
Daniella Moreira Salvadé ◽  
...  
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Dry Matter ◽  
Direct Methods ◽  
Area Index ◽  
Area Estimation ◽  
Sowing Dates ◽  
Plant Densities ◽  
Area Determination

The knowledge of the variables specific leaf area and leaf area index is important for direct or indirect quantification of plant growth, development and yield. However, there is a lack of these information due to the difficulty in measuring the leaf area of chamomile. Measuring leaf area by direct methods, such as the use of leaf area integrator is a very laborious and time consuming activity because the plant has many leaves and with small size. The use of leaf dry matter is a promising variable for the leaf area estimation. As an important measure to evaluate plant growth, the present study aimed to obtain a model for chamomile leaf area estimation through leaf dry matter. The experiment was conducted in two sowing dates (March 18 and June 30, 2017) at different plant densities (66, 33, 22, 16, 13, 11 and 8 plants m-2). The leaves of chamomile plants were collected in the plant vegetative and reproductive phases. The leaf area determination was performed using the electronic integration method of leaf area. The specific leaf area was 133 cm2 g-1, with no differences between sowing dates, plant densities and phenological phases of plant collection. The leaf area measured with the electronic leaf area integrator exhibited high correlation with chamomile leaf dry matter and the resulting model of leaf area data by the integrator presented optimum performance. This model is indicated for leaf area determination of chamomile when there is availability of leaf dry matter data.

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