The effect of changing plant density on floral initiation and development of barley (cv. Sultan)

1971 ◽  
Vol 77 (1) ◽  
pp. 135-139 ◽  
Author(s):  
R. R. B. Leakey
Keyword(s):  
Plant Density ◽  
Tiller Number ◽  
Downward Trend ◽  
Low Density ◽  
Floral Initiation ◽  
Ear Development ◽  
Plastic Character

SummaryBarley plants were grown at low, high, increasing and decreasing densities in an attempt to manipulate the environment. The effects on tiller production and development were measured.Increasing density with time had less effect than decreasing it. Tiller number was the most plastic character, tiller production being earlier in those plants which emerged into low density, being delayed or inhibited in other treatments. The number of spikelets/ear and the length of the inflorescence were found to be less stable characters than the stage of ear development. Percentage spikelet survival showed a downward trend, with increasing density stress.

Day-length influence on reproductive development and tillering in ‘Fergus’ barley

1975 ◽  
Vol 53 (23) ◽  
pp. 2770-2775 ◽  
Author(s):  
D. T. Fairey ◽  
L. A. Hunt ◽  
N. C. Stoskopf
Keyword(s):  
Hordeum Vulgare ◽  
Reproductive Development ◽  
Tiller Number ◽  
Day Length ◽  
Floral Initiation ◽  
Internode Elongation ◽  
Spikelet Number ◽  
Hordeum Vulgare L ◽  
Initial Formation ◽  
Double Ridge

Effects of variation in day length on spikelet and tiller development were studied in a two-rowed barley, Hordeum vulgare L. cultivar ‘Fergus.’ Spikelet number and the length of the spikelet-forming phase increased with progressive reductions in day length from 24 to 12 h. However, increases in spikelet number were offset by abortion of spikelet primordia during spikelet differentiation and elongation of the stem internodes. Floral initiation occurred at all day lengths, but intemode elongation and heading were markedly delayed at 12 h. The cessation of spikelet initial formation and the beginning of internode elongation did not occur simultaneously in any day length. The latter began just before or at double ridge formation.Tiller numbers were highest at 12 h and progressively decreased in longer day lengths. Each plant produced four primary tillers at all day lengths, and differences in tiller number were accounted for by secondary and tertiary tiller production.

scholarly journals Plant Yield Efficiency by Homeostasis as Selection Tool at Ultra-Low Density. A Comparative Study with Common Stability Measures in Maize

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1203
Author(s):  
Evaggelia Sinapidou ◽  
Chrysanthi Pankou ◽  
Fotakis Gekas ◽  
Iosif Sistanis ◽  
Constantinos Tzantarmas ◽  
...  
Keyword(s):  
Plant Density ◽  
Phenotypic Expression ◽  
Yield Potential ◽  
Low Density ◽  
Potential Yield ◽  
Plant Yield ◽  
Yield Efficiency ◽  
Parametric Statistics ◽  
Resource Deficit ◽  
Field Experimentation

The study pertains to field experimentation testing seven maize (Zea mays L.) hybrids at four densities, across five locations under normal (NIR) and low-input (LIR) regimes. The main objective was to assess the prognostic value of plant yield efficiency by homeostasis (PYEH) for breeding purposes at ultra-low plant density to predict hybrid yield potential and stability. PYEH comprises plant yield efficiency (PYE) that reflects the ability of individual plants to exploit resources, and plant yield homeostasis (PYH) that indicates the crop’s ability to evade acquired plant-to-plant variability. The same hybrids were also evaluated for stability by commonly used parametric and non-parametric statistics based on data at low (LCD) and high crop densities (HCD). Hybrid stability focused on potential yield loss due to erratic optimum density (OD). Most methods produced conflicting results regarding hybrid ranking for yield and stability especially at LCD. In contrast, PYEH consistently highlighted high-yielding and stable hybrids, potentially able to reach the attainable crop yield (ACY) inter-seasonally irrespective of crop spacing. Low density is common practice under resource-deficit conditions, so crop adaptation to crop spacing is a viable option to overcome erratic OD that constitutes a root source of crop instability in rainfed maize. The results were further supportive of breeding at ultra-low density to facilitate the identification and selection of superior genotypes, since such conditions promote phenotypic expression and differentiation, and ensure repeatability across diverse environments.

Determination of spikelet number in wheat. I. Effect of varying photoperiod on ear development

1977 ◽  
Vol 28 (2) ◽  
pp. 265 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Floral Initiation ◽  
Wheat Cultivars ◽  
Spikelet Number ◽  
Shoot Apices ◽  
Rate Of Development ◽  
Ear Development ◽  
Main Factors ◽  
Photoperiod Control

The effects of constant photoperiods (8, 9, 10, normal and 24 hr) and of transfer to another photoperiod at floral initiation (from 24 hr to 10 and vice versa) on rate of development and spikelet number per ear were studied in eight wheat cultivars grown at 20°C. The objective was to know what factors related to photoperiod control spikelet number. The lengths of the vegetative, spikelet and ear elongation phases, the numbers of spikelets and leaves, the numbers of phytomers and lengths of the shoot apices at floral initiation increased, but the rate of spikelet initiation decreased, as the photoperiod decreased from 24 to 8 hr. Responses to varying photoperiod for all these parameters were similar in the different cultivars but the sizes of the responses differed. Within a given cultivar, an increase in spikelet number was always associated with longer durations of the vegetative and spikelet phases and longer apices at floral initiation. The results of the transfer treatments suggest that spikelet number is not fully determined by the time of floral initiation, but can be altered significantly by manipulating the environment during the spikelet phase. It was concluded that the main factors determining spikelet number are rate and duration of spikelet initiation.

The effect of plant density upon the growth and yield of barley

1967 ◽  
Vol 68 (3) ◽  
pp. 317-324 ◽  
Author(s):  
E. J. M. Kirby
Keyword(s):  
Seedling Establishment ◽  
Yield Components ◽  
Plant Density ◽  
Growth Parameters ◽  
Tiller Number ◽  
Growth And Yield ◽  
Wide Range ◽  
Cereal Plant ◽  
Variety Effect ◽  
Ear Number

1. Cereal plant density affects yield and growth parameters of fundamental importance. An experiment is described in which growth and development, and yield and yield components of barley grown over a wide range of density were examined.2. Four varieties of barley—Proctor, Plumage-Archer, Domen, and Moore—were grown at densities approximately equivalent to 35, 70, 140 and 280 lb/acre. Density was found not to affect seedling establishment or plant survival, but there was a variety effect on seedling establishment.3. Varietal differences were seen in maximum tiller number, and the percentage of tillers surviving to form ears. These differences were most marked between the six-row variety and two-row varieties. The effect of increasing density was to increase the maximum tiller number, but this was followed by different rates of tiller death until early June, after which there was no further compensation for tiller number. Ear emergence and ear number were affected both by variety and density.

Determination of spikelet number in wheat. III.* Effect of varying temperature on ear development

1978 ◽  
Vol 29 (3) ◽  
pp. 459 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Floral Initiation ◽  
Wheat Cultivars ◽  
Variable Response ◽  
Spikelet Number ◽  
Rate Of Development ◽  
Ear Development ◽  
Elongation Phase

The effects on rate of development and spikelet number per ear in eight wheat cultivars grown at various temperatures (16/9, 23/16, and 30/23°C for 8/16 hr) throughout or transferred from one temperature to another at floral initiation were studied under normal (12.5–14.0 hr) and 24 hr photoperiods. Under a 24 hr photoperiod, the durations of the vegetative, spikelet and elongation phases, and spikelet number per ear decreased as the temperature increased from 16/9 to 30/23°C in all cultivars. The rate of spikelet initiation increased as temperature increased from 16/9 to 23/16° in most cultivars, but further increase in temperature caused a variable response. Under a normal photoperiod, increasing the temperature from 16/9 to 23/16°C changed spikelet number little, but further increase in temperature decreased it in most cultivars. The rate of initiation increased, but the durations of the vegetative, spikelet and elongation phases, and the apex length at floral initiation decreased in all cultivars as the temperature increased from 16/9 to 23/16°; with further increase in temperature, the rate of initiation, apex length and duration of the elongation phase decreased in most cultivars, but the durations of the vegetative and spikelet phases either increased or changed little. Variation in the number of spikelets per ear in relation to variation in the factors considered to be its possible determinants is discussed with a view to understanding the control of spikelet number. ___________________ *Part II, Aust. J. Agric. Res., 28: 575 (1977).

scholarly journals Spacing experiments with brussels sprouts grown for single-pick harvests.

1970 ◽  
Vol 18 (1) ◽  
pp. 89-104
Author(s):  
E.W.M. Verheij
Keyword(s):  
Dry Matter ◽  
Plant Density ◽  
High Density ◽  
Average Weight ◽  
Low Density ◽  
Planting Pattern ◽  
Brussels Sprouts ◽  
Wide Range ◽  
Plant Densities ◽  
Time Of Harvest

Two-year trials are discussed on the effects of different spacings, planting pattern and row orientation, stopping the plants, and time of harvest on the cropping, habit and root growth of the hybrid brussels sprouts variety Thor. Yields of dry matter per sq.m. rose sharply with increasing plant density up to about 4 plants per sq.m., above which there was little further increase. The average weight per plant, however, showed the reverse trend, and declined with closer spacing. The total yields of sprouts from unstopped plants attained a maximum at a density of about 1 plant per sq.m., but the maximum yields and numbers of marketable sprouts were obtained with densities of about 2 and 2 plants per sq.m., respectively. Plants grown at high densities were taller and more slender than low-density plants, a habit well suited to mechanical stripping. Moreover, the sprouts from high-density plants were more uniform, which facilitated grading. There was little difference between the number and distribution of the roots, including depth of rooting, over a wide range of plant densities. However, high-density plants had fewer thick roots, and at the widest spacings the total number of roots per sq.m. declined. The pattern of planting had a slight influence on the height of the low-density plants, but differential effects of various row orientations were negligible. Stopping the plants greatly increased the total yields of sprouts at all densities; the numbers of marketable sprouts from the stopped plants were also greater, especially at densities of 3 plants per sq.m. and above. Harvesting stopped plants in late October instead of late September resulted in much higher yields of sprouts at all densities except the lowest, despite a decline in the fresh weights of the plants during this period.-I.T.T., Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Rooting and plant density strongly determine greenhouse gas budget of water hyacinth (<i>Eichhornia crassipes</i>) mats

2016 ◽  
Author(s):  
Ernandes Sobreira Oliveira Junior ◽  
Yingying Tang ◽  
Sanne J. P. van den Berg ◽  
Leon P. M. Lamers ◽  
Sarian Kosten
Keyword(s):  
Greenhouse Gas ◽  
Growth Rates ◽  
Water Hyacinth ◽  
Nutrient Dynamics ◽  
Plant Density ◽  
High Growth ◽  
High Density ◽  
Low Density ◽  
Nutrient Pool ◽  
Chimney Effect

Abstract. Water hyacinth occurs in numerous tropical and subtropical countries, either as a native or as an invasive exotic species, where it can establish large and dense mats. The plant is also frequently used for water purification and bioremediation purposes. Although it is a free-floating species, the plant roots into the sediment of shallow waters, tapping into the sediment nutrient pool. Its long and extensive root system strongly increases nutrient absorption, resulting in high growth rates and concurring high carbon sequestration rates. On the other hand, the plants may also fuel methane (CH4) production as dense mats may deplete oxygen in the surface water and sediment below, which in combination with the high production of organic matter creates favorable conditions for methanogenesis. We hypothesize that water hyacinth vegetation acts as a strong greenhouse gas (GHG) sink due to its high growth rates, especially when (sediment) nutrient availability is high. Still, this sink may be counterbalanced by CH4 release, which will be most pronounced when the plants are rooting in the sediment due to potential CH4 shuttling from the sediment through the roots and leaves into the atmosphere (chimney effect). To mechanistically unravel the influence of water hyacinth on nutrient dynamics and greenhouse gas fluxes, we performed an aquarium experiment in which plant density and root access to the sediment were manipulated. Although plant cover led to lower concentrations of dissolved total phosphorus (DTP) and phosphate, there were no effects of density or rooting. We found no vegetation effect on the ebullition of CH4, but its diffusion was 4.5 times higher at high plant coverage. Rooting increased CH4 diffusion by 1.3 (high density) and 4 times (low density), demonstrating the chimney effect that we hypothesized. Independent of rooting, however, water hyacinth at high density sequestrated less carbon compared to low density, possibly due to space limited growth and self-shading. Overall, water hyacinth enhanced CH4 emissions, especially when rooted. Due to water hyacinth's high CO2 sequestration rates, the overall GHG budget in terms of CO2 equivalents still resulted in water hyacinth mats being near-neutral or even a GHG sink, depending on water hyacinth density. Our results show that the effect of water hyacinth mats on GHG fluxes strongly depends on both plant density and contact with the sediment. This indicates that, when making regional GHG balances, not only plant presence but also its density and water depth – regulating sediment-root contact – should be taken into account.

Grain yield in determinate and indeterminate cultivars of Vicia faba with different plant distribution patterns and population densities

1992 ◽  
Vol 118 (3) ◽  
pp. 343-352 ◽  
Author(s):  
H. Stützel ◽  
W. Aufhammer
Keyword(s):  
Vicia Faba ◽  
Growth Rates ◽  
Plant Density ◽  
Distribution Patterns ◽  
Crop Growth ◽  
Plant Distribution ◽  
Low Density ◽  
Seed Filling ◽  
High Plant Density ◽  
Plant Distribution Patterns

SUMMARYA determinate and an indeterminate cultivar of Vicia faba were grown in the field to study the effects of two different plant densities and three plant distribution patterns on yield formation. The relationship between crop growth rate during flowering and the number of pods produced was identical in both cultivars. The higher growth rates of the indeterminate cultivar and of dense stands were associated with higher pod numbers. Average crop growth rates in the period between flowering and 30 days thereafter were related to the number of mature seed-containing pods. This relationship was similar in both cultivars except that the determinate cultivar aborted seed-containing pods as late as 40–45 days after flowering when grown at the low density. Rates of seed filling for both cultivars were similar at the low density (c 1·4 mg per °C per day per pod), but were larger for the determinate cultivar at the high density. The annual differences in seed weights per pod were not related to seed filling rates. Grain yields and harvest indices were generally lower in the determinate than in the indeterminate cultivar, but high plant density increased seed yields of the determinate more than of the indeterminate, because of an increase in harvest index. Plant distribution pattern had no significant effect on the above characters.

Selection at ultra-low density identifies plants escaping virus infection and leads towards high-performing lentil (Lens culinaris L.) varieties

2013 ◽  
Vol 152 (5) ◽  
pp. 749-758 ◽  
Author(s):  
A. KARGIOTIDOU ◽  
E. CHATZIVASSILIOU ◽  
C. TZANTARMAS ◽  
E. SINAPIDOU ◽  
A. PAPAGEORGIOU ◽  
...  
Keyword(s):  
Virus Infection ◽  
Mosaic Virus ◽  
Lens Culinaris ◽  
Plant Density ◽  
Phenotypic Variability ◽  
Pure Line ◽  
Yellow Mosaic Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Density ◽  
High Performing

SUMMARYCultivated lentil (Lens culinaris L.) landraces offer a challenge to exploiting their genetic variability and deriving new pure-line varieties. For insect-transmitted viruses, low densities favour increased virus spread. The objective of the present work was to evaluate a selection procedure applied within a landrace under ultra-low plant density and low-input conditions toward the isolation of high-performing genotypes that escape virus infection. Field trials were conducted through four growing seasons (2006–2011) in the Democritus University of Thrace research farm in Orestiada, Greece. Selection of individual plants for high grain yield was applied for three generations, while virus presence was tested by enzyme-linked immunosorbent assay in the seeds used or the plants selected in each selection cycle. Early high plant-to-plant phenotypic variability, reflected by high coefficient of variation (CV) values, was partly attributed to virus infection. However, sister lines were consistently higher yielding and of lower CV than the mother population (MP). Second generation lines yielded up to 136 and 23% more than the source landrace at the ultra-low density and dense stand, respectively. Pea seed-borne mosaic virus was detected in the seeds of the MP, whereas bean yellow mosaic virus and bean leafroll virus were mainly involved in the subsequent selection rounds. In general, the highest-yielding plants were free of the viruses detected during experimentation. It was concluded that selection at ultra-low density of the highest-yielding plants from the sister lines with the lowest CV constitute an effective way to improve the health status of the seeds produced and result in high yielding and potentially virus-tolerant pure-line varieties.

scholarly journals Ear development and formation of grain yield in winter wheat.

1980 ◽  
Vol 28 (3) ◽  
pp. 156-163 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Plant Density ◽  
Grain Filling ◽  
Wheat Crop ◽  
Grain Production ◽  
Ear Development ◽  
Growing Period ◽  
Plant Densities ◽  
Winter Wheat Crop

The pattern of grain production of a winter wheat crop and the effect of plant density and time of tiller emergence on grain yield/ear were studied. At harvest, ear size and ear components were ascertained and were discussed in relation to ear growth and ear development during the prefloral and postfloral growing period. Detailed information was obtained on the productivity of ear-bearing tillers and their contribution to final grain yield. Shoot productivity decreased in denser crops; ears were smaller because spikelet differentiation, grain set and grain filling were inadequate. The date that the tiller emerged largely determined its subsequent grain yield. With later tiller initiation and emergence fewer ears were produced. Moreover, these ears were smaller because spikelet initiation, spikelet differentiation, grain set and grain filling were reduced. At low and moderate plant densities, the grain yield of the early-emerged tillers only slightly lagged behind that of main shoots and max. grain yield could be achieved at moderate plant densities. It was concluded that in cereal farming, high and stable grain yields are aims to be achieved. These can be best achieved by having moderate plant densities and applying correct treatments for good crop growth. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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