Small grain screenings in wheat—using the grain size distribution for predicting cultivar responses

2006 ◽  
Vol 57 (7) ◽  
pp. 771 ◽  
Author(s):  
D. L. Sharma ◽  
M. F. D'Antuono ◽  
W. K. Anderson
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Laplace Distribution ◽  
Grain Weight ◽  
Average Weight ◽  
Grain Length ◽  
Breeding Material ◽  
Small Width ◽  
Flour Yield

Small grain is a concern for wheat growers in water-limited environments worldwide. Following from our preliminary results that cultivars can differ for small grain screenings despite similarity of average grain weight in wheat, grain size distribution was investigated with the aim of identifying alternative parameters that could more reliably discriminate cultivars for their tendency to screenings without actually subjecting breeding material to harsh environments. Pre-cleaned harvest samples (using screen with 1.5-mm-wide holes) of 5 cultivars from 2 field cultivar × time of sowing experiments were divided into 5 grain-width fractions using 4 sieves with holes from 2.5 to 3.4-mm wide. The experiments conducted in the Western Australian wheatbelt experienced a dry finish in 2000 and a relatively wetter year in 2003. The grain that was separated into each width fraction was weighed and the average weight of grains for each fraction (called the size-specific weight) was derived from a subsample. The weight of grain (expressed as a percentage of the whole) collected between the 2.8 and 3.1-mm screens (fraction F3) was highly and negatively correlated with small grain screenings (r = –0.85; P < 0.001), thus strengthening the perception that screenings percentages may follow a certain form of grain size distribution. Among various grain size distributions, the skew-Laplace distribution fitted on grain weight was found to be the most suitable to characterise the cultivars. This provides a general approach in the examination of a grain size distribution, which is invariant to combinations of sieve sizes that different individuals may choose. We conclude that: (i) parameters µ and 1/α of the skew-Laplace distribution based on grain weight separated into each fraction can be used as a selection tool in predicting propensity for small grain screenings in wheat without having to subject breeding material to harsh conditions; (ii) higher values for both µ and 1/α are desirable but if the cultivar has small µ, a high 1/α is required to reduce screenings; (iii) breeders could consider the grain size distribution in addition to grain weight as a breeding objective; and (iv) millers should be looking for higher average grain weight and higher weight per unit grain length especially at small width fractions, to maximise flour yield. Hence, we anticipate that future research into aspects of starch packaging such as grain shape and endosperm density will optimise grain size distribution, grain weight per unit grain length, and eventually the flour yield per unit land area.

Use of grain size distribution parameters to explain variation in small grain screenings of wheat in multi-environment trials involving new cultivars

2009 ◽  
Vol 60 (7) ◽  
pp. 658
Author(s):  
D. L. Sharma ◽  
B. J. Shackley ◽  
M. Amjad ◽  
C. M. Zaicou-Kunesch ◽  
M. F. D'Antuono ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Kernel Weight ◽  
Grain Weight ◽  
High Yield ◽  
Future Research ◽  
Plant Structure ◽  
Nitrogen Inputs ◽  
Distribution Parameters

The proportion of small grain screenings is a worldwide problem for wheat growers in water-limited environments and is known to be influenced by both genetic and environmental factors including crop management. This paper follows our previous finding that parameters μ (reflecting point of majority mass of the grain size distribution) and 1/α (reflecting the slope of grain size distribution up to the majority point) of a skew-Laplace distribution can be used to differentiate the tendency of cultivars to produce small grains. The variability of these parameters over environments (15 Cultivar × Time of sowing and 2 Cultivar × Plant population × Nitrogen rates experiments) was investigated in order to indicate their utility in breeding cultivars and managing wheat crops. The estimated values of both μ and 1/α varied over experiments but the relative cultivar ranking remained similar. Of the genetic and management factors, cultivar had more effect on variance of μ than of 1/α, while applied nitrogen level significantly influenced 1/α. We conclude that: (i) cultivars can be grouped according to their μ and 1/α values; (ii) cultivars owing their lower screenings to high 1/α need a careful optimising of nitrogen inputs, while breeding for high μ is likely to provide stability against small grain screenings; (iii) both the parameters were associated with kernel weight and grains/spike but not grains/m2; and (iv) future research establishing the relationship of 1/α with specific kernel position within the plant will be useful in proposing an ideal ear and plant structure for minimising small grain screenings. When using parameters of the suggested grain size distribution, we suggest the following relevant points be considered: (i) 1/α is not a linear slope, it is related to ‘skewness’; (ii) the peak at majority mass (MM) reflects the tendency to concentrate grain mass and therefore provides an opportunity to increase skewness (1/α) despite a lower μ and a lower mean grain weight; (iii) there is a point up to which skewness of grain size distribution can sufficiently protect against high screenings and is highly dependent upon the value of μ; and (iv) 1/α is a potentially useful parameter nonetheless, because in practice, grain weight may be reduced as number of grains/area is increased in pursuit of high yield through breeding and agronomic practices.

Grain size distribution in evaporated permalloy films

1970 ◽  
Vol 2 (2) ◽  
pp. K69-K73 ◽  
Author(s):  
M. Reinbold ◽  
H. Hoffmann
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

scholarly journals Influence of bimodal grain size distribution on the corrosion resistance of Mg-4Li-3Al-1Zn (LAZ431)

2021 ◽  
Author(s):  
Anna Dobkowska ◽  
Boguslawa Adamczyk – Cieślak ◽  
Dariusz Kuc ◽  
Eugeniusz Hadasik ◽  
Tomasz Płociński ◽  
...  
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Bimodal Grain Size ◽  
Bimodal Grain Size Distribution

scholarly journals Effect of Strain-Induced Precipitation on the Recrystallization Kinetics in a Model Alloy

2021 ◽  
Author(s):  
Mo Ji ◽  
Martin Strangwood ◽  
Claire Davis
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Avrami Exponent ◽  
Model Alloy ◽  
Size Distributions ◽  
Recrystallization Kinetics ◽  
Grain Size Distributions ◽  
Recrystallized Grain Size ◽  
Nb Addition

AbstractThe effects of Nb addition on the recrystallization kinetics and the recrystallized grain size distribution after cold deformation were investigated by using Fe-30Ni and Fe-30Ni-0.044 wt pct Nb steel with comparable starting grain size distributions. The samples were deformed to 0.3 strain at room temperature followed by annealing at 950 °C to 850 °C for various times; the microstructural evolution and the grain size distribution of non- and fully recrystallized samples were characterized, along with the strain-induced precipitates (SIPs) and their size and volume fraction evolution. It was found that Nb addition has little effect on recrystallized grain size distribution, whereas Nb precipitation kinetics (SIP size and number density) affects the recrystallization Avrami exponent depending on the annealing temperature. Faster precipitation coarsening rates at high temperature (950 °C to 900 °C) led to slower recrystallization kinetics but no change on Avrami exponent, despite precipitation occurring before recrystallization. Whereas a slower precipitation coarsening rate at 850 °C gave fine-sized strain-induced precipitates that were effective in reducing the recrystallization Avrami exponent after 50 pct of recrystallization. Both solute drag and precipitation pinning effects have been added onto the JMAK model to account the effect of Nb content on recrystallization Avrami exponent for samples with large grain size distributions.

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