Some relationships between plant population, yield components and grain yield of wheat in a Mediterranean environment

1986 ◽  
Vol 37 (3) ◽  
pp. 219 ◽  
Author(s):  
WK Anderson
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Plant Density ◽  
Plant Population ◽  
Individual Plant ◽  
Spring Bread Wheat ◽  
Grain Yields ◽  
Optimum Population ◽  
Large Numbers ◽  
The Relationship

Eight spring bread wheat cultivars (Triticum aestivum L.), differing widely in their nominal yield component characteristics, were tested under rain-fed conditions for three years at sowing densities ranging from 50 to 800 seeds m-2. The objectives of the experiments were to estimate the relationship between grain yield and particular yield components, the expression of plant type (yield components) in relation to plant density, and the plant population x cultivar interaction for grain yield over a range of seasons in a given environment. The 'optimum' plant population (at maximum grain yield) varied over 30-220 plants m-2, depending on season and cultivar. In general, variation in the 'optimum' population was greater between seasons for a given cultivar than between cultivars within seasons. The relationship between grain yield and yield components was examined at the 'optimum' population rather than at an arbitrary population at which grain yield may have been suboptimal for some cultivars or seasons. Grain yields at the optimum populations for the various cultivar x season combinations were positively related to culms m-2, spikes m-2 and seeds m-2. They were not clearly related to culm mortality (%). When averaged across seasons, cultivar grain yields were positively related to harvest index, but the general relationship was not so clear when seasons and cultivars were examined individually. Spike size (seeds spike-I or spike weight) and seed size were also not clearly related to grain yield at the 'optimum' population, and it was thus postulated that the production and survival of large numbers of culms, which in turn led to large numbers of seeds per unit area, were the source of large grain yields. Some interactions were found between yield components and plant population for some cultivars that could have implications for plant breeders selecting at low plant densities. The implications for crop ideotypes of the individual plant characters at the 'optimum' population are also discussed. Interactions between cultivars and plant populations implied that some cultivars required different populations to achieve maximum yields in some seasons. There was a tendency for larger yields to be achieved from cultivar x season combinations where the optimum population was larger, which suggested that commercial seed rates should be re-examined when changes to plant types or yield levels are made.

scholarly journals Increasing population density reduces soybean yield components and productivity

2021 ◽  
Vol 37 ◽  
pp. e37042
Author(s):  
Marcelo De Almeida Silva ◽  
Ana Carolina De Santana Soares ◽  
Melina Rodrigues Alves Carnietto ◽  
Alexandrius De Moraes Barbosa
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Spatial Arrangement ◽  
Plant Population ◽  
Row Spacing ◽  
Individual Plant ◽  
Growth Type ◽  
Soybean Yield ◽  
Plant Densities ◽  
Plant Yields

Studies addressing the interaction of different spatial arrangement in soybean are needed in order to achieve management that leads to higher grain yield associated with rational seed use. The objective of this work was to evaluate the yield components and productivity of an undetermined growth type soybean as a function of different row spacing and plant densities. The treatments consisted of three row spaces (0.25, 0.35 and 0.45 m) and three plant population densities (30, 40 and 50 plants/m²). There was no interaction of row spaces and plant population on soybean yield. Regarding the overall spacing average, the grain yield of the population of 30/m² plants was higher than the productivity of the populations of 40 and 50/m² plants. The largest populations reduce plant sizes due to greater competition between plants. In addition, smaller populations promote higher individual plant yields due to the increase components of the production. This characteristic is defined as the ability of the plant to change its morphology and yield components in order to adapt to the conditions imposed by the spatial arrangement.

Rainfall, sowing time, soil type, and cultivar influence optimum plant population for wheat in Western Australia

2004 ◽  
Vol 55 (9) ◽  
pp. 921 ◽  
Author(s):  
W. K. Anderson ◽  
D. L. Sharma ◽  
B. J. Shackley ◽  
M. F. D'Antuono
Keyword(s):  
Grain Yield ◽  
Soil Type ◽  
Yield Components ◽  
Regression Tree ◽  
Growing Season ◽  
Sowing Date ◽  
Plant Population ◽  
Plant Populations ◽  
Optimum Population ◽  
Growing Conditions

In this paper we analyse existing experimental data (grain yield and yield components) from seed rate experiments on wheat in Western Australia, with the aims of determining which factors most influence the optimum plant population, and advancing some practical guidelines for improving the choice of seed rate under rain-fed conditions. Experiments (32) were conducted in the rain-fed cropping zone of Western Australia between 1996 and 2001, using factorial combinations of wheat cultivars (3–25) and target plant populations (4 or 5). Some of them also contained treatments of nitrogen fertiliser (0 or 40 kg/ha of N) or sowing times (2). Each cultivar × plant population dataset (248) was considered to be a record for the sake of the subsequent analyses. Actual plant numbers were counted in each experiment and the optimum plant population was estimated when the slope of an inverse polynomial curve (choosing the most appropriate of the LDL and QDL models in GenStat) fitted to each record was 2.5 kg/ha of grain yield for each extra plant/m2. The optimum populations were initially grouped using a regression tree technique into groups with similar characteristics using pre-sowing rainfall, rainfall in the growing season, sowing date, and soil type. The variables cultivar and nitrogen fertiliser rate were later added to the regression tree analysis. Yield components available for most experiments were used as an aid to interpretation of the results. The optimum plant population varied from 35 to 175 plants/m2 and average grain yields varied from 0.42 to 3.91 t/ha. Rainfall in the growing season (sowing date to harvest date) provided the first split in the regression tree, but pre-sowing rainfall (January to sowing date), sowing date, and soil type further modified the optimum population. The addition of N fertiliser rate as a variable in the regression tree did not induce any different groupings of the optimum population sets, but cultivars were grouped into 4 response types according to pre- and post-sowing rainfall amounts. Where rainfall in the growing season was <205 mm, improved growing conditions due to more pre-sowing rainfall, earlier sowing, and more seasonal rainfall, were associated with higher optimum plant populations. Where rainfall in the growing season exceeded 205 mm, higher pre-sowing rainfall was associated with lower optimum populations. The optimum population was greater on sands than on clay loams. However, on sandy loam soils the optimum was less where rainfall in the growing season was <291 mm, or more for crops sown after 27 May at rainfall >291 mm. Increases in yield components in response to improved growing conditions above about 400 culms/m2, 300 ears/m2, 10 000 kernels/m2, and 600 g/m2 of dry matter at anthesis were not associated with higher optimum plant populations. In general, the optimum plant population increased at about 40 plants/m2 for each tonne of grain yield up to about 3.0 t/ha. The effect of cultivar on the optimum population appeared at yield levels above 2.5 t/ha, but was only detectable when the rainfall in the growing season exceeded 205 mm. Growing conditions and cultivars associated with lower weight per ear (due to fewer kernels and/or lower kernel weight) were associated with higher optimum plant population when the rainfall in the growing season exceeded 205 mm. It is suggested that farmers can make better estimates of the appropriate plant population (and hence can calculate seed rate) on the basis of pre-sowing rainfall (likely stored water), rainfall zone (probability of rainfall in the growing season), sowing date, soil type, and characteristics of individual cultivars where known.

scholarly journals Optimizing Grain Yield and Water Use Efficiency Based on the Relationship between Leaf Area Index and Evapotranspiration

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 313
Author(s):  
Guoqiang Zhang ◽  
Bo Ming ◽  
Dongping Shen ◽  
Ruizhi Xie ◽  
Peng Hou ◽  
...  
Keyword(s):  
Grain Yield ◽  
Water Use Efficiency ◽  
Leaf Area Index ◽  
Water Use ◽  
Plant Density ◽  
Maize Yield ◽  
Area Index ◽  
Irrigation Level ◽  
Use Efficiency ◽  
The Relationship

Achieving optimal balance between maize yield and water use efficiency is an important challenge for irrigation maize production in arid areas. In this study, we conducted an experiment in Xinjiang China in 2016 and 2017 to quantify the response of maize yield and water use to plant density and irrigation schedules. The treatments included four irrigation levels: 360 (W1), 480 (W2), 600 (W3), and 720 mm (W4), and five plant densities: 7.5 (D1), 9.0 (D2), 10.5 (D3), 12.0 (D4), and 13.5 plants m−2 (D5). The results showed that increasing the plant density and the irrigation level could both significantly increase the leaf area index (LAI). However, LAI expansion significantly increased evapotranspiration (ETa) under irrigation. The combination of irrigation level 600 mm (W3) and plant density 12.0 plants m−2 (D4) produced the highest maize yield (21.0–21.2 t ha−1), ETa (784.1–797.8 mm), and water use efficiency (WUE) (2.64–2.70 kg m−3), with an LAI of 8.5–8.7 at the silking stage. The relationship between LAI and grain yield and evapotranspiration were quantified, and, based on this, the relationship between water use and maize productivity was analyzed. Moreover, the optimal LAI was established to determine the reasonable irrigation level and coordinate the relationship between the increase in grain yield and the decrease in water use efficiency.

scholarly journals Determination of leaf area coefficient in sunflower.

1977 ◽  
Vol 25 (4) ◽  
pp. 238-242
Author(s):  
A.S.R. Pereira
Keyword(s):  
Leaf Area ◽  
Yield Components ◽  
Plant Density ◽  
Photosynthetic Capacity ◽  
Leaf Position ◽  
Area Estimation ◽  
End Use ◽  
The Relationship

For studies on the relationship between photosynthetic capacity and yield components in sunflower a method for estimating leaf area was required. To this end use of the leaf area coefficient (LAC), i.e. the quotient area/(length X max. width), was evaluated. It was found that LAC may be a function of leaf position and plant density, depending on the cv. concerned. For the Russian cv. Armavirec, LAC was independent of leaf position and plant density. For the Rumanian hybrid HS 18, LAC was dependent on leaf position but not plant density. For the French hybrid INRA 4701, LAC depended on both leaf position and plant density, but even in this case, it was concluded that LAC can be a useful aid in leaf area estimation. (Abstract retrieved from CAB Abstracts by CABI’s permission)

THE RELATIONSHIP BETWEEN FINAL YIELD AND PHOTOSYNTHESIS AT FLOWERING IN INDIVIDUAL MAIZE PLANTS

1979 ◽  
Vol 59 (3) ◽  
pp. 585-601 ◽  
Author(s):  
G. O. EDMEADES ◽  
T. B. DAYNARD
Keyword(s):  
Grain Yield ◽  
Shoot Growth ◽  
Plant Density ◽  
Meteorological Data ◽  
Dry Weight ◽  
Plant Variation ◽  
Final Yield ◽  
Black Layer ◽  
Maize Plants ◽  
The Relationship

In an attempt to explain plant-to-plant variation in dry weight of maize (Zea mays L.), a computer program was developed to predict daily assimilation per plant and its distribution throughout the shoot at flowering. Inputs to the model were meteorological data, photosynthetic rate-irradiance curves, measurements of intraplant assimilate distribution at flowering, and the positions of individual leaves of plants grown in the field at three densities (50 000, 100 000 and 150 000 plants/ha). Dry weights were recorded on these same plants following black layer formation. Predicted effects of plant density on shoot growth compared favorably with available data. The correlation coefficient between predicted assimilation 1 day after anthesis and grain yield on the same plants, with treatment effects removed, was 0.67 (N = 360). The coefficient of variation of predicted assimilate flux per plant increased significantly with increasing density, and the fluxes were generally normally distributed. Results supported the concept of a threshold assimilation rate per plant below which grain would not normally form, and this appears to be the cause of the bimodal frequency distribution of grain yield per plant observed at high densities.

Grain Yield Gains and Associated Traits in Tropical X Temperate Maize Germplasm Under High and Low Plant Density

2021 ◽  
Author(s):  
Vince Ndou ◽  
Edmore Gasura ◽  
Pauline Chivenge ◽  
John Derera
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Plant Density ◽  
Plant Population ◽  
Population Densities ◽  
Genetic Gains ◽  
Maize Germplasm ◽  
High Plant Density ◽  
Number Of Leaves ◽  
Plant Population Density

Abstract Development of ideal breeding and crop management strategies that can improve maize grain yield under tropical environments is crucial. In the temperate regions, such yield improvements were achieved through use of genotypes that adapt high plant population density stress. However, tropical germplasm has poor tolerance to high plant population density stress, and thus it should be improved by temperate maize. The aim of this study was to estimate the genetic gains and identify traits associated with such gains in stable and high yielding temperate x tropical hybrids under low and high plant population densities. A total of 200 hybrids derived from a line x tester mating design of tropical x temperate germplasm were developed. These hybrids were evaluated for grain yield and allied traits under varied plant population densities. High yielding and stable hybrids, such as 15XH214, 15XH215 and 15XH121 were resistant to lodging and had higher number of leaves above the cob. The high genetic gains of 26% and desirable stress tolerance indices of these hybrids made them better performers over check hybrids under high plant population density. At high plant population density yield was correlated to stem lodging and number of leaves above the cob. Future gains in grain yield of these hybrids derived from temperate x tropical maize germplasm can be achieved by exploiting indirect selection for resistance to stem lodging and increased number of leaves above the cob under high plant density conditions.

scholarly journals Thermal Imaging Reliability for Estimating Grain Yield and Carbon Isotope Discrimination in Wheat Genotypes: Importance of the Environmental Conditions

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2676 ◽  
Author(s):  
Sebastián Romero-Bravo ◽  
Ana María Méndez-Espinoza ◽  
Miguel Garriga ◽  
Félix Estrada ◽  
Alejandro Escobar ◽  
...  
Keyword(s):  
Grain Yield ◽  
Thermal Imaging ◽  
Mediterranean Climate ◽  
Vapor Pressure Deficit ◽  
Stress Condition ◽  
Water Status ◽  
Canopy Temperature ◽  
Spring Bread Wheat ◽  
Wheat Genotypes ◽  
The Relationship

Canopy temperature (Tc) by thermal imaging is a useful tool to study plant water status and estimate other crop traits. This work seeks to estimate grain yield (GY) and carbon discrimination (Δ13C) from stress degree day (SDD = Tc − air temperature, Ta), considering the effect of a number of environmental variables such as the averages of the maximum vapor pressure deficit (VPDmax) and the ambient temperature (Tmax), and the soil water content (SWC). For this, a set of 384 and a subset of 16 genotypes of spring bread wheat were evaluated in two Mediterranean-climate sites under water stress (WS) and full irrigation (FI) conditions, in 2011 and 2012, and 2014 and 2015, respectively. The relationship between the GY of the 384 wheat genotypes and SDD was negative and highly significant in 2011 (r2 = 0.52 to 0.68), but not significant in 2012 (r2 = 0.03 to 0.12). Under WS, the average GY, Δ13C, and SDD of wheat genotypes growing in ten environments were more associated with changes in VPDmax and Tmax than with the SWC. Therefore, the amount of water available to the plant is not enough information to assume that a particular genotype is experiencing a stress condition.

scholarly journals Interference of GR® Volunteer Corn Population and Origin on Soybean Grain Yield Losses

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
C. PIASECKI ◽  
M.A. RIZZARDI ◽  
D.P. SCHWADE ◽  
M. TRES ◽  
J. SARTORI
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Individual Plant ◽  
Soybean Yield ◽  
Maximum Loss ◽  
Tillage System ◽  
Volunteer Corn ◽  
Corn Plants ◽  
F2 Generation ◽  
The Impact

ABSTRACT: The cultivation of GR® maize prior to soybean, mainly in the no-tillage system favors the higher occurrence of GR® volunteer corn interfering in soybean crops. Volunteer corn originate from seeds that were lost during harvest or from non-harvested seeds from the field; these are individual seeds, originating individual plants, or several seeds adhered to segments of the rachis, which originate clumps. Volunteer corn in the form of clumps predominates in soybean crops, but little information about its effect on soybean is available in the literature. During two years, three experiments were carried out with the objective of evaluate the impact of the interference of GR® F2 generation volunteer corn populations coming from individual and clump seeds (seven corn plants emerged at the same point) over soybean yield components and grain yield. The results show that losses in soybean yield components and grain yield are influenced by the population and origin of volunteer corn. Clumps cause losses over 90% for populations above four clumps m-2, while the mean maximum loss observed for individual plants was 83% in the largest studied populations. Soybean yield decreased significantly when competing with populations below one plant or clump m-2, being 16% and 46% in the population of 0.5 individual plant and clump m-2, respectively.

Effectiveness of some copper compounds applied as foliar sprays in alleviating copper deficiency of wheat grown on copper-deficient soils of Western Australia

1990 ◽  
Vol 30 (5) ◽  
pp. 687 ◽  
Author(s):  
RF Brennan
Keyword(s):  
Grain Yield ◽  
Western Australia ◽  
Copper Deficiency ◽  
Relative Effectiveness ◽  
Grain Yields ◽  
Foliar Sprays ◽  
Cu Deficiency ◽  
Copper Compounds ◽  
The Difference ◽  
The Relationship

The effectiveness of copper oxychloride (CU2Cl(OH)3, 52% Cu) and chelated Cu (Cu-EDTA, 15% Cu) were compared with the effectiveness of copper sulphate (CuSO4, 25% Cu) as foliar sprays for alleviating Cu deficiency and obtaining maximum grain yields of wheat (1.93-2.5 t/ha). The experiments were conducted over 4 years at 4 sites in the Lake Grace and Newdegate districts, about 300-350 km south-east of Perth, Western Australia. Each source was sprayed at 6 or 7 rates of Cu to define the relationship between grain yield and the amount of foliar Cu applied for wheat grown on soils where Cu had not been previously applied. The levels of Cu sprayed in experiment 1 were 0, 21, 63, 125, 250, and 375 g/ha, and for experiments 2,3 and 4, the levels of Cu were 0, 25, 50, 100, 200, 400 and 800 g/ha. The relative effectiveness of foliar-applied chelated Cu and CU2Cl(OH)3, compared with CuSO4, was 1.72-2.24 and 0.47-0.63, respectively. Although the relative effectiveness of each product was different, similar quantities of each were required to achieve maximum wheat grain yield because of the difference in the Cu contents of each source of Cu. The amounts of Cu product sprayed for maximum grain yields of wheat varied within the ranges 0.9-1.8 kg/ha, 0.8-1.2 kg/ha and 0.8-1.8 kg/ha for CuSO4, chelated Cu and CU2Cl(OH)3, respectively.

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