Population and Spacing Studies with Malawian Groundnut Cultivars

1974 ◽  
Vol 10 (3) ◽  
pp. 177-184 ◽  
Author(s):  
R. C. N. Laurence
Keyword(s):  
Inverse Relationship ◽  
Plant Density ◽  
Kernel Weight ◽  
Plant Population ◽  
Variable Component ◽  
Kernel Size ◽  
Plant Habit ◽  
Commercially Important ◽  
Very High ◽  
Pod Number

SUMMARYThe effects of plant population on the yields of four commercially important Malawian groundnut cultivars have been investigated. Pod number per plant was found to be the most variable component, bearing an inverse relationship to plant density. Kernel weight and shelling percentage were low at reduced populations, and yields and kernel size declined at very high populations. The effect of plant habit upon spacing requirement is discussed and recommendations are made.

scholarly journals Managing Density Stress to Close the Maize Yield Gap

2021 ◽  
Vol 12 ◽  
Author(s):  
Eric T. Winans ◽  
Tryston A. Beyrer ◽  
Frederick E. Below
Keyword(s):  
Plant Density ◽  
Maize Yield ◽  
Kernel Weight ◽  
Plant Population ◽  
Management Control ◽  
Yield Gap ◽  
Induced Stress ◽  
Agronomic Management ◽  
Standard Level ◽  
N Fertility

Continued yield increases of maize (Zea mays L.) will require higher planting populations, and enhancement of other agronomic inputs could alleviate density-induced stress. Row spacing, plant population, P-S-Zn fertility, K-B fertility, N fertility, and foliar protection were evaluated for their individual and cumulative impacts on the productivity of maize in a maize-soybean [Glycine max (L.) Merr.] rotation. An incomplete factorial design with these agronomic factors in both 0.76 and 0.51 m row widths was implemented for 13 trials in Illinois, United States, from 2014 to 2018. The agronomic treatments were compared to two controls: enhanced and standard, comprising all the factors applied at the enhanced or standard level, respectively. The 0.51 m enhanced management control yielded 3.3 Mg ha–1 (1.8–4.6 Mg ha–1 across the environments) more grain (25%) than the 0.76 m standard management control, demonstrating the apparent yield gap between traditional farm practices and attainable yield through enhanced agronomic management. Narrow rows and the combination of P-S-Zn and K-B fertility were the factors that provided the most significant yield increases over the standard control. Increasing plant population from 79,000 to 109,000 plants ha–1 reduced the yield gap when all other inputs were applied at the enhanced level. However, increasing plant population alone did not increase yield when no other factors were enhanced. Some agronomic factors, such as narrow rows and availability of plant nutrition, become more critical with increasing plant population when density-induced stress is more significant. Changes in yield were dependent upon changes in kernel number. Kernel weight was the heaviest when all the management factors were applied at the enhanced level while only planting 79,000 plants ha–1. Conversely, kernel weight was the lightest when increasing population to 109,000 plants ha–1 while all other factors were applied at the standard level. The yield contribution of each factor was generally greater when applied in combination with all other enhanced factors than when added individually to the standard input system. Additionally, the full value of high-input agronomic management was only realized when matched with greater plant density.

scholarly journals Development of Efficient and Selective Processes for the Synthesis of Commercially Important Chlorinated Phenols

Organics ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 142-160
Author(s):  
Keith Smith ◽  
Gamal A. El-Hiti
Keyword(s):  
Lewis Acid ◽  
Large Scale ◽  
Commercial Application ◽  
Chlorinated Phenols ◽  
Sulphur Compounds ◽  
Inorganic Solids ◽  
Solvent Free Conditions ◽  
Commercially Important ◽  
Ortho Cresol ◽  
Very High

para-Selective processes for the chlorination of phenols using sulphuryl chloride in the presence of various sulphur-containing catalysts have been successfully developed. Several chlorinated phenols, especially those derived by para-chlorination of phenol, ortho-cresol, meta-cresol, and meta-xylenol, are of significant commercial importance, but chlorination reactions of such phenols are not always as regioselective as would be desirable. We, therefore, undertook the challenge of developing suitable catalysts that might promote greater regioselectivity under conditions that might still be applicable for the commercial manufacture of products on a large scale. In this review, we chart our progress in this endeavour from early studies involving inorganic solids as potential catalysts, through the use of simple dialkyl sulphides, which were effective but unsuitable for commercial application, and through a variety of other types of sulphur compounds, to the eventual identification of particular poly(alkylene sulphide)s as very useful catalysts. When used in conjunction with a Lewis acid such as aluminium or ferric chloride as an activator, and with sulphuryl chloride as the reagent, quantitative yields of chlorophenols can be obtained with very high regioselectivity in the presence of tiny amounts of the polymeric sulphides, usually in solvent-free conditions (unless the phenol starting material is solid at temperatures even above about 50 °C). Notably, poly(alkylene sulphide)s containing longer spacer groups are particularly para-selective in the chlorination of m-cresol and m-xylenol, while, ones with shorter spacers are particularly para-selective in the chlorination of phenol, 2-chlorophenol, and o-cresol. Such chlorination processes result in some of the highest para/ortho ratios reported for the chlorination of phenols.

Effects of Plant Density and Thinning on High-Yielding Dry Beans (Phaseolus vulgaris) in Mexíco

1977 ◽  
Vol 13 (4) ◽  
pp. 325-335 ◽  
Author(s):  
Aguilar M. Immer ◽  
R. A. Fischer ◽  
Joshue Kohashi S.
Keyword(s):  
Phaseolus Vulgaris ◽  
Leaf Area ◽  
Seed Weight ◽  
Plant Density ◽  
Plant Competition ◽  
Growth And Yield ◽  
Positive Relation ◽  
Dry Beans ◽  
Leaf Area Duration ◽  
Pod Number

SUMMARYThe influence of leaf area and inter-plant competition on the growth and yield of a crop of high-yielding dry beans (Phaseolus vulgaris L.) in central Mexico was studied, using density and thinning treatments. The highest seed yield (4210 kg/ha at 14% moisture) was obtained with the highest density (28·8 plants/m2). Thinning showed that pods/plant was sensitive to inter-plant competition between 36 and 78 days after seeding (first flower at 50 days), but seeds/pod, and especially seed weight, were not sensitive. It is suggested that the close positive relation between yield and leaf area duration derives from the influence of photosynthate supply upon pod number.

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.

Effects of high plant populations on the growth and yield of winter oilseed rape (Brassica napus)

1999 ◽  
Vol 132 (2) ◽  
pp. 173-180 ◽  
Author(s):  
J. E. LEACH ◽  
H. J. STEVENSON ◽  
A. J. RAINBOW ◽  
L. A. MULLEN
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Plant Density ◽  
High Density ◽  
Growth And Yield ◽  
Winter Oilseed Rape ◽  
Plant Populations ◽  
Rothamsted Experimental Station ◽  
Plant Densities ◽  
Very High

The effects of plant density on the growth and yield of winter oilseed rape (Brassica napus) were examined in a series of five multifactorial experiments at Rothamsted Experimental Station between 1984 and 1989. Plant densities, manipulated by changing the seed rate and row spacing, or because of overwinter losses, ranged from 13·5 to 372 plants/m2. Normalized yields for the multifactorial plots increased with densities up to 50–60 plants/m2. In very high density plots in 1987/88, yield decreased as density increased >150 plants/m2. Plants grown at high density had fewer pod-bearing branches per plant but produced more branches/m2. Branch dry matter (DM) per plant was decreased by 42%, the number of fertile pods per plant and pod DM/plant by 37%. There was no effect of density on the number or DM of pods/m2. Over 74% of the fertile pods were carried on the terminal and uppermost branches of plants grown at high density in 1987/88 compared with only 34% in plants grown at low density in 1988/89. Seed DM/plant decreased with increase in density but seed size (1000-seed weight) increased. There was no effect of density on seed glucosinolate or oil contents.

Yield response of narrow-leafed lupin plants to variations in pod number

1998 ◽  
Vol 49 (1) ◽  
pp. 63 ◽  
Author(s):  
J. A. Palta ◽  
C. Ludwig
Keyword(s):  
Seed Size ◽  
Seed Yield ◽  
Plant Density ◽  
Yield Response ◽  
Seed Number ◽  
Subsequent Removal ◽  
Seed Filling ◽  
Specific Number ◽  
Pod Number ◽  
Number Of Seeds

The effect of pod number on the seed yield and components of seed yield was examined for narrow-leafed lupin (Lupinus angustifolius L.) grown at a plant density of 36 plants/m2 in both the glasshouse and the field. Diflerent numbers of pods per plant in the glasshouse-grown lupin were generated by the application of N6-benzylaminopurine (BAP) to a specific number of flowers to ensure artificially that they set pods, and the subsequent removal of the remaining untreated flowers. Pod number ranged from 6 to 65 pods/plant in the glasshouse and was naturally distributed from 2 to 22 pods/plant in the field. Increases in seed yield per plant occurred as pod number per plant increased from 2 to 30 pods. No further increases in seed yield resulted when pod number per plant increased from 30 to 55 pods. Seed yield per plant was depressed as pod number increased from 55 to 65 pods. Seed size fell as pod number per plant increased over 20 pods and was less affected once the number of seeds per pod was reduced. The reduction in seed number per pod resulted from an increase in the number of seeds that aborted during seed filling. The data suggest that at a plant density of 36 plants/m2 there is potential for improving seed yield per plant by increasing the number of pods that reach maturity, provided it does not exceed 30 pods/plant. However, if consideration is given to producing large seeds, often preferred by buyers, the number of pods per plant should not exceed 20 pods.

Relationship between extract viscosity and kernel size in winter rye

1998 ◽  
Vol 78 (3) ◽  
pp. 423-427
Author(s):  
Y. T. Gan ◽  
J. G. McLeod ◽  
G. J. Scoles ◽  
G. L. Campbell
Keyword(s):  
Secale Cereale ◽  
Kernel Weight ◽  
Selection Strategy ◽  
Winter Rye ◽  
Kernel Size ◽  
Kernel Width ◽  
Secale Cereale L ◽  
The Relationship ◽  
Efficient Selection ◽  
Selection Of

Rye (Secale cereale L.) grain with low extract viscosity (EV) and superior kernel characteristics is desired when used in diets of monogastric animals. Knowledge of the relationship between EV and kernel characteristics is needed to develop an efficient selection strategy for breeding cultivars that meet the two criteria. Grains of 11 open-pollinated population varieties/lines grown in 21 environments were studied to determine the relationship between EV and kernel weight (KWT) among genotypes and environmental effects. Grains of eight out of the eleven varieties/lines were screened into five kernel-size categories, <2.0, 2.0–2.4, 2.4–2.8, 2.8–3.2, >3.2 mm in kernel width, to determine the relationship between EV and kernel width within a genotype. EV was a linear function of KWT; high KWT is indicative of low EV. The degree of the relationship was affected by environment. For example, grains grown at Swift Current had a stronger relationship between EV and KWT than those from Lacombe (b = −1.67 vs. −0.31). For the grain from Swift Current, 60% of variability in EV was attributable to KWT, while for the grain from Lacombe only ≈ 20% of variability in EV was explainable by KWT. Among the various kernel-width categories within a genotype, 60 to 98% of variability in EV was attributable to kernel width, with some genotypes responding to a greater degree than others. In development of winter rye cultivars low in extract viscosity, breeders could combine kernel weight/width into the selection strategy to enhance the selection progress or use kernel weight/width as a reference in selection of extract viscosity trait. Key words: Pentosans, arabinoxylans, kernel weight, Secale cereale

QUALIDADE NA COLHEITA MECANIZADA DE MILHO SEMEADO EM DIFERENTES VELOCIDADES

2016 ◽  
Vol 15 (3) ◽  
pp. 582 ◽  
Author(s):  
ANTONIO TASSIO SANTANA ORMOND ◽  
MURILO APARECIDO VOLTARELLI ◽  
CARLA SEGATTO STRINI PAIXÃO ◽  
ALINE SPAGGIARI ALCÂNTARA1 ◽  
ELIZABETH HARUNA KAZAMA ◽  
...  
Keyword(s):  
Process Control ◽  
Statistical Process Control ◽  
Plant Density ◽  
Plant Population ◽  
Longitudinal Distribution ◽  
Statistical Control ◽  
Individual Values ◽  
Sowing Time ◽  
Statistical Process

RESUMO - As perdas na colheita podem estar relacionadas tanto a colhedora, como também a fatores ligados a cultura como: mau preparo do solo, densidade de plantas, inadequação da época de semeadura são alguns deles. O presente estudo objetivou determinar a influência da velocidade de semeadura no processo de colheita mecanizada de milho, por meio do controle de qualidade do processo. O experimento foi conduzido em Latossolo Vermelho, textura argilosa e relevo suave ondulado. O delineamento foi baseado na óptica do Controle Estatístico de ProcessoCEP, onde os dados foram coletados em pontos aleatórios em função do tempo. Os indicadores de qualidade avaliados foram divididos em parâmetros de semeadura (população de plantas e distribuição longitudinal de plântulas); e de colheita (Perdas de grãos e distribuição de palha) em função de seis velocidades de deslocamento (aproximadamente 2,0; 4,0; 6,0; 9,0; 10,0 e 12,0 Km.h-1). Os dados foram submetidos a análise descritiva para análise do comportamento. Como ferramentas do controle estatístico de processo utilizou-se, run charts ou gráfico sequencial e carta de controle de valores individuais para análise da qualidade do processo. A maior velocidade (V6) apresentou a maior variabilidade dos dados para todas as variáveis. A operação da colheita mecanizada de milho foi influenciada por fatores extrínsecos e intrínsecos a ela.Palavras-chave: Controle estatístico de processo, espaçamentos normais, perdas, população de plantas.QUALITY IN MECHANIZED HARVEST OF CORN SOWN IN DIFFERENT SPEEDSABSTRACT - The harvest losses may be associated to harvester as well as factors related to cultivation such as poor soil preparation, plant density, unsuitable sowing time. This study aimed to determine the effect of speed sowing in the mechanized harvest of corn, through the control of the quality of the process. The experiment was conducted in a clayey Oxisol and undulate relief. The design was based on the optics of the Statistical Process Control SPC, and the data were collected at random points in function of time. The quality indicators evaluated were divided into sowing parameters (plant population and longitudinal distribution of seedlings) and harvesting (loss of grain and straw distribution) in function of six displacement speeds (approximately 2.0, 4.0, 6.0, 9.0, 10.0 and 12.0 Km.h-1). The data were submitted to descriptive analysis for behavior analysis. As tools for the statistical control of the process, run charts or sequential graph were used, and control chart of individual values for analysis of the quality of the process. The highest speed (V6) showed the highest variability of the data for all variables. The operation of mechanized harvest of corn was influenced by extrinsic and intrinsic factors.Keywords: statistical process control, normal spacings, losses, plant population.

Yield-density relationships and optimum plant populations in two cultivars of solid-seeded dry bean (Phaseolus vulgaris L.) grown in Saskatchewan

2002 ◽  
Vol 82 (3) ◽  
pp. 521-529 ◽  
Author(s):  
Steven J. Shirtliffe ◽  
Adrian M. Johnston
Keyword(s):  
Seed Weight ◽  
Plant Density ◽  
Maximum Yield ◽  
Plant Population ◽  
Seeding Density ◽  
Seeding Rate ◽  
Higher Plant ◽  
Plant Populations ◽  
Dry Bean ◽  
Density Relationship

There is relatively little agronomic information on solid-seeded production of dry bean in western Canada. Recommended seeding density for dry bean can depend on the growth habit of the plant, the yield–density relationship, percent emergence, seed cost and environment. The objective of this study was to determine the yield–density relationships in two determinate bush type cultivars of dry bean and the optimum plant population under solid-seeded production in Saskatchewan. CDC Camino, a late-season pinto bean and CDC Expresso, a medium-season-length black bean were the cultivars evaluated. In most sites, the yield-density relationship of the cultivars was asymptotic and an optimum plant density for maximum yield could not be determined. Camino generally required a lower plant population to reach a given yield than Expresso. Increasing plant population did not affect 1000-seed weight. Higher seeding rate did result in a greater number of seeds produced m-2, with Expresso having a greater increase in seed produced m-2 compared with Camino. Expresso was required to be at higher plant densities than Camino to maximize economic returns. This reflects the differences between cultivars in yield-density relationship and seed cost, as Camino has a heavier 1000-seed weight than Expresso. Saskatchewan bean growers wishing to maximize profit should target plant populations for Expresso and Camino of approximately 50 and 25 plants m-2, respectively. Key words: Saskatchewan, yield components, non-linear regression, seeding rate, narrow rows, solid-seeded

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.

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