Genotype by environment interactions affecting grain sorghum. III. Temporal sequences and spatial patterns in the target population of environments

2000 ◽  
Vol 51 (2) ◽  
pp. 223 ◽  
Author(s):  
S. C. Chapman ◽  
G. L. Hammer ◽  
D. G. Butler ◽  
M. Cooper
Keyword(s):  
Soil Type ◽  
Target Population ◽  
Soil Types ◽  
Stress Index ◽  
Variable Environments ◽  
Eastern Australia ◽  
Variable Nature ◽  
North Eastern ◽  
Farm Profit ◽  
The Difference

The variable nature of rainfall in north-eastern Australia confounds the process of selecting sorghum hybrids that are broadly adapted. This paper uses a crop simulation model to characterise the drought environment types (ET) that occur in the target population of environments (TPE) for dryland sorghum. Seventy seasons (1921–1990) of simulations of the yield of a sorghum genotype and the associated within-season sequence of a stress index were conducted for a small TPE of 6 locations and also for a large TPE of 211 locations that attempted to represent the entire sorghum region. Previously, using the small dataset of 6 locations, pattern analysis enabled us to group seasonal stress indices from each trial into major ETs: ‘low terminal stress’ (ET1), severe terminal stress (ET2), and intermediate mid-season/terminal stress (ET3) in the ratio 33 : 38 : 29. When the dataset was broken into a sequence of 16 multi-environment trials (METs), each of 3 years and 6 locations, the ratios of ET1 : ET2 : ET3 differed greatly among METs, i.e. any single MET was not randomly sampling the TPE. Hence, for any MET, the average yield (GVu) was not the same as the overall mean of the entire 70-year dataset. If the trial yields were weighted according to the ratio of ET1 : ET2 : ET3 in the overall TPE, then GVw (s.d. = 0.13) for a single MET was much closer to the overall mean than was GVu (0.38). For different METs, the values of GVw were up to 30% higher or 15% lower than GVu. Across METs, the difference between GVu and GVw was positively correlated (r = 0.88, n = 16, P < 0.05) with the frequency of ET1 (‘low terminal stress’) encountered within the MET and negatively correlated (r = −0.82) with the frequency of ET2. The value of weighting was confirmed by its ability to verify that two simulated genotypes had the same mean yield over many trials, even though they differed in their specific adaptation to the different ETs. The large TPE consisted of more than 15 000 simulations and was classified in 2 stages (within/among locations), repeated for each of 3 soil types. In years in which the simulation sowing criteria were met, the ratios of ET1 : ET2 : ET3 were about 4:2:4, 4:5:1, and 6:3:1 in the shallow, intermediate, and deep soils, respectively. Hence, over all soil types and locations, the sorghum TPE for northern Australia consists of at least 30% each of low terminal stress (ET1) or severe terminal stress (ET2) and these environment types need to be sampled. The incidence and nature of the ‘intermediate midseason/terminal stress’ environment type (ET3) varies with soil type and location. Weighting genotype performance should improve the precision of the estimate of its broadly adapted value, and be of practical use in breeding programs in these variable environments. Although the ‘boundary conditions’ of the TPE are not yet resolved, this paper also shows that simulation and pattern analyses can be used to determine the structure of the abiotic TPE. Taking other factors into account (e.g. soil type distribution, shire production levels, and farm profit), selection trials could be weighted to improve selection for narrow or broad adaptation, depending on the purpose of the breeding program.

Using crop simulation to generate genotype by environment interaction effects for sorghum in water-limited environments

2002 ◽  
Vol 53 (4) ◽  
pp. 379 ◽  
Author(s):  
Scott C. Chapman ◽  
Mark Cooper ◽  
Graeme L. Hammer
Keyword(s):  
Cropping Systems ◽  
Target Population ◽  
Genotype By Environment Interaction ◽  
Expected Improvement ◽  
Stress Index ◽  
Environment Interaction ◽  
Genotype By Environment ◽  
Systems Model ◽  
Water Stress Index ◽  
Eastern Australia

Multi-environment trials (METs) used to evaluate breeding lines vary in the number of years that they sample. We used a cropping systems model to simulate the target population of environments (TPE) for 6 locations over 108 years for 54 ‘near-isolines’ of sorghum in north-eastern Australia. For a single reference genotype, each of 547 trials was clustered into 1 of 3 ‘drought environment types’ (DETs) based on a seasonal water stress index. Within sequential METs of 2 years duration, the frequencies of these drought patterns often differed substantially from those derived for the entire TPE. This was reflected in variation in the mean yield of the reference genotype. For the TPE and for 2-year METs, restricted maximum likelihood methods were used to estimate components of genotypic and genotype by environment variance. These also varied substantially, although not in direct correlation with frequency of occurrence of different DETs over a 2-year period. Combined analysis over different numbers of seasons demonstrated the expected improvement in the correlation between MET estimates of genotype performance and the overall genotype averages as the number of seasons in the MET was increased.

Genotype by environment interactions affecting grain sorghum. I. Characteristics that confound interpretation of hybrid yield

2000 ◽  
Vol 51 (2) ◽  
pp. 197 ◽  
Author(s):  
S. C. Chapman ◽  
M. Cooper ◽  
D. G. Butler ◽  
R. G. Henzell
Keyword(s):  
Variance Components ◽  
Genetic Correlations ◽  
Target Population ◽  
Breeding Strategies ◽  
Random Set ◽  
Crop Water ◽  
Genotype By Environment ◽  
Eastern Australia ◽  
North Eastern ◽  
Seasonal Weather

Past sorghum hybrid trials in north-eastern Australia have detected substantial genotype by environment (G×E) interactions for yield in sampling a variable target population of environments (TPE) that is affected by spatial and seasonal differences in crop water supply. Three datasets, comprising yields of commercial and final stage experimental hybrids and covering 9–17 years (Y) and up to 30 locations (L), were analysed to quantify variance components for trial error, genotypic (σ2g), and G×E (σ2gl, σ;2gy, and σ2gly) interaction effects. Whereas trial means varied 2–3-fold across seasons, a greater range was estimated for variance components of trial error (range of 0.05–0.5), G (0–>0.3), and G×L interaction (0.05–>1.0). There was substantial seasonal variation in the ratio of σ2g to (σ2g +σ2gl), and in two datasets, 73% of the seasonal σ2gl was due to poor genetic correlations among locations. This implies that any given set of hybrids in a random set of locations would be ranked differently from season to season. Analysis of locations over years detected 90% of the total G×E interaction as G×L×Y, rather than G×L or G×Y, although this was reduced by accounting for genotype maturity. To achieve repeatabilities of >80%, trials would need to be conducted over at least 5 years and 20 locations per year. The variable and unpredictable nature of much of the G×E interaction in the region implies that broad adaptation to different water regimes is required, unless prior knowledge of the seasonal weather can be used to choose ‘narrowly adapted’ cultivars. With current approaches, a large sample of environments is needed to identify such hybrids, and testing across locations and years is equally important. Alternative breeding strategies based on classifying environment types are discussed.

Magnesium in tropical and subtropical soils from north-eastern Australia. I. Magnesium fractions and interrelationships with soil properties

Soil Research ◽  
1997 ◽  
Vol 35 (3) ◽  
pp. 615 ◽  
Author(s):  
K. J. Hailes ◽  
R. L. Aitken ◽  
N. W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Plant Growth ◽  
Clay Content ◽  
Soil Types ◽  
Mg Deficiency ◽  
Eastern Australia ◽  
North Eastern ◽  
Subtropical Soils ◽  
Mg Content

The magnesium (Mg) status of 52 highly weathered, predominantly acidic, surface soils from tropical and subtropical north-eastern Australia was evaluated in a laboratory study. Soils were selected to represent a range of soil types and management histories. Exchangeable Mg concentrations were generally low (median value 0·37 cmol(+)/kg), with deficient levels (<0·3 cmol(+)/kg) being measured in 22 of the soils, highlighting the potential for Mg deficiency as a limitation to plant growth in the region. Furthermore, acid-extractable Mg concentrations, considered a reserve of potentially available Mg, were generally modest (mean and median values, 1·6 and 0·40 cmol(+)/kg, respectively). The total Mg content of the soils studied ranged from 123 to 7894 mg/kg, the majority present in the mineral pool (mean 71%), with smaller proportions in the acid-soluble (mean 11%) and exchangeable (mean 17%) pools, and a negligible amount associated with organic matter (mean 1%). A range of extractant solutions used to displace exchangeable Mg was compared, and found to yield similar results on soils with exchangeable Mg <4 cmol(+)/kg. However, at higher exchangeable Mg concentrations, dilute extractants (0·01 M CaCl2, 0·0125 BaCl2) displaced less Mg than concentrated extractants (1 M NH4Cl, 1 M NH4OAc, 1 M KCl). The concentrated extractants displaced similar amounts of Mg, thus the choice of extractant is not critical, provided the displacing cation is sufficiently concentrated. Exchangeable Mg was not significantly correlated to organic carbon (P > 0·05), and only 45% of the variation in exchangeable Mg could be explained by a combination of pHw and clay content.

Soils of the Poplar Box (Eucalyptus populnea) communities of Eastern Australia.

1980 ◽  
Vol 2 (1) ◽  
pp. 17 ◽  
Author(s):  
AA Webb ◽  
PJ Walker ◽  
RH Gunn ◽  
AT Mortlock
Keyword(s):  
Soil Type ◽  
New South ◽  
Chemical Properties ◽  
Soil Types ◽  
Physical And Chemical Properties ◽  
South Wales ◽  
Eastern Australia ◽  
Physical And Chemical ◽  
Eucalyptus Populnea ◽  
And Chemical Properties

Information on the soils of recognized poplar box (Eucalyptus populnea) communities has been collated from published and unpublished reports. Major soils have been described briefly in terms of morphology and some physical and chemical properties. Site data from a number of previous surveys was used in an attempt to identify soil type/vegeration relationships. Poplar box occurs on a very \\'ide range of soil types. Approximately half of the 1500 sites described in Queensland and New South Wales were on duple\ soils. The data indicate that poplar box prefers lighter textured soils such as uniform sands and massive earths in the western areas of its distribution but in the eastern, more mesic areas il occurs mainly on duplex clay soits.

scholarly journals Properties of humic acids depending on the land use in different parts of Slovakia

2021 ◽  
Author(s):  
Magdalena Banach-Szott ◽  
Bozena Debska ◽  
Erika Tobiasova
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Size Distribution ◽  
Humic Acids ◽  
Forest Ecosystem ◽  
Soil Type ◽  
Soil Types ◽  
Organic Matter Quality ◽  
Degree Of Maturity ◽  
Effects Of Land Use

AbstractMany studies report organic carbon stabilization by clay minerals, but the effects of land use and soil type on the properties of humic acids (HAs) are missing. The aim of the paper is to determine the effects of land use and soil types on the characteristics of HAs, which have a considerable influence on organic matter quality. It was hypothesised that the effect of the land use on HAs properties depends on the particular size distribution. The research was performed in three ecosystems: agricultural, forest, and meadow, located in Slovakia. From each of them, the samples of 4 soil types were taken: Chernozem, Luvisol, Planosol, and Cambisol. The soil samples were assayed for the content of total organic carbon (TOC) and the particle size distribution. HAs were extracted with the Schnitzer method and analysed for the elemental composition, spectrometric parameters in the UV-VIS range, and hydrophilic and hydrophobic properties, and the infrared spectra were produced. The research results have shown that the properties of HAs can be modified by the land use and the scope and that the direction of changes depends on the soil type. The HAs of Chernozem and Luvisol in the agri-ecosystem were identified with a higher “degree of maturity”, as reflected by atomic ratios (H/C, O/C, O/H), absorbance coefficients, and the FT-IR spectra, as compared with the HAs of the meadow and forest ecosystem. However, as for the HAs of Cambisol, a higher “degree of maturity” was demonstrated for the meadow ecosystem, as compared with the HAs of the agri- and forest ecosystem. The present research has clearly identified that the content of clay is the factor determining the HAs properties. Soils with a higher content of the clay fraction contain HAs with a higher “degree of maturity”.

THE OASIS SOIL TYPE CHANGE AND ITS FRACTAL IN MANASI RIVER BASIN BETWEEN 1987–2006, ARID NORTHWESTERN CHINA / MANASI UPĖS BASEINO SAUSRINGOJE ŠIAURĖS VAKARŲ KINIJOJE OAZIŲ DIRVOŽEMIO TIPŲ POKYČIAI IR FRAKTALAI 1987–2006 M

2012 ◽  
Vol 20 (3) ◽  
pp. 177-184 ◽  
Author(s):  
Pujia Yu ◽  
Hailiang Xu ◽  
Shiwei Liu ◽  
Xinfeng Zhao ◽  
Qingqing Zhang ◽  
...  
Keyword(s):  
River Basin ◽  
Soil Type ◽  
Stability Index ◽  
Rapid Expansion ◽  
Soil Types ◽  
Semiarid Region ◽  
Arid Northwestern China ◽  
Type Change ◽  
The Stability ◽  
Soil Changes

During the past 20 years, great landscape changes took place in the northwest of China. Landscape change resulted in soil type transformations. This paper discusses the changes and fractal of soil types in oasis. In order to do it, the soil type maps of Manasi River Basin in 1987 and 2006 were used. 13 types of soil and 2 types of land-use were classified and analyzed in the study area. Results indicated many variations in characteristics. Firstly, all soil types underwent remarkable changes from 1987 to 2006 in the study area: the identified changed area was about 30% or 6506.33 km2. Secondly, in comparison with 1987, in 2006 2/3 of the area's soil types increased, while 1/3 decreased. Rapid expansion of Aquicambids (415.28 km2), and rapid decrease of Petrocambids (797.05 km2) and Aquisalids (415.93 km2) were the noticeable findings. Furthermore, Haplocambids obtained largest gains from other soil types, while Petrocambids lost largest area to other types. Additionally, the fractal relationship objectively existed between the perimeter and area of soil patches. The fractal dimension of Aquisalids, Petrocalcids and Ustifluvents became higher and their shapes became more complex during this period. The stability index was higher in 2006 which indicated that the spatial structure of soil type was more stable than in 1987. These chaotic and occasional changes were largely caused by human activities and natural conditions. Consequently, environmental managers should pay more attention to soil changes in the arid and semiarid region. Santrauka Per pastaruosius 20 metų šiaurės vakarų Kinijoje įvyko didelių kraštovaizdžio pokyčių, lėmusių ir dirvožemio tipų pakitimus. Remiantis 1987–2006 m. Manasi upės baseino dirvožemio žemėlapiais, aptariami dirvožemio tipų pokyčiai ir fraktalai oazėse. Pasirinktoje teritorijoje išskirta ir analizuota 13 dirvožemio tipų ir dvejopa žemėnauda. Nustatyta daug kintamųjų parametrų. Pirma, tirtõs teritorijos visų tipų dirvožemiai nuo 1987 iki 2006 m. žymiai pakito. Nustatytoji pokyčių zona apima apie 30 % teritorijos, arba 6 506,32 km2. Antra, palyginti su 1987 m., 2006 m. 10 dirvožemio tipų teritorija padidėjo, o 5 tipų sumažėjo. Sparčiai padidėjo Aquicambids (415,28 km2), sparčiai sumažėjo Petrocambids (797,05 km2) ir Aquisalids (415,93 km2), pokyčiai buvo žymūs. Iš visų kitų pakitusių dirvožemių tipų Haplocambids plotai padidėjo daugiausia, o labiausiai, palyginti su kitais, sumažėjo Petrocambids plotai. Be to, pastebėta, kad tarp dirvožemio teritorijos plotų ir perimetrų objektyviai egzistuoja fraktalinės sąsajos. Fraktalinės dimensijos Aquisalids, Petrocalcids ir Ustifluvents per minėtą laikotarpį padidėjo, o jų formos tapo sudėtingesnės. Stabilumo indeksas 2006 m. buvo didesnis. Tai rodė, kad erdvinė dirvožemio struktūra mažai pakito, tapo stabilesnė, palyginti nei buvo 1987 m. Šiuos atsitiktinius pokyčius iš esmės lėmė žmogaus veikla ir gamtinės sąlygos. Prieita prie išvados, kad sausojo ar pusiau sauso klimato regionuose kraštotvarkos vykdytojai dirvožemio pokyčiams turėtų skirti daugiau dėmesio.

Freshwater Cyanobacteria of North-Eastern Australia: 2. Chroococcales

Phytotaxa ◽  
2013 ◽  
Vol 133 (1) ◽  
pp. 1 ◽  
Author(s):  
GLENN B. MCGREGOR
Keyword(s):  
Light Microscopy ◽  
Natural Populations ◽  
Northern Territory ◽  
Detailed Account ◽  
Ecological Data ◽  
Eastern Australia ◽  
North Eastern ◽  
Rivers And Streams ◽  
Original Illustrations ◽  
Freshwater Habitats

This volume provides the first detailed account of the Chroococcales of north-eastern Australia. It provides keys, morphological and ecological data for 6 families, 33 genera and 112 species, and photomicrographs and original illustrations to enable the identification of natural populations based on stable and recognizable characters observable with the aid of light microscopy. Distributional data are based on extensive surveys at 270 sites representing the major freshwater habitats including rivers and streams, palustrine and lacustrine wetlands, thermal springs, and man-made reservoirs in Queensland and the Northern Territory as well as a review of the Australian phycological literature. 

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