Compensating for site and year effects in estimating the true yield of wheat genotypes

1975 ◽  
Vol 26 (5) ◽  
pp. 783 ◽  
Author(s):  
DG Pederson ◽  
E Seif
Keyword(s):  
New South ◽  
Wheat Yield ◽  
Regression Coefficients ◽  
Biased Sampling ◽  
Wheat Cultivars ◽  
Dominant Effect ◽  
Phenotypic Stability ◽  
Yield Data ◽  
South Wales ◽  
Approximate Equality

When data are obtained for several cultivars over years and sites, it is possible to calculate three regression coefficients for each cultivar, based on site x cultivar effects, year x cultivar effects, and site x year x cultivar effects respectively. For wheat yield data from western New South Wales there is an approximate equality of these measures of phenotypic stability, and it is inferred that a single environmental factor has a dominant effect both between and within seasons. This result is applied to the estimation of a regression mean for each cultivar, a technique designed to compensate for the biased sampling of environments over one or two seasons. For nine wheat cultivars, it is shown that the regression mean is at least as good an estimator of true yield as the arithmetic mean, and the conditions under which a regression mean is expected to be a better estimator are defined.

Time of sowing and wheat yield in northern New South Wales

1974 ◽  
Vol 14 (66) ◽  
pp. 93 ◽  
Author(s):  
AD Doyle ◽  
H Marcellos
Keyword(s):  
Grain Yield ◽  
New South ◽  
New South Wales ◽  
Wheat Yield ◽  
Wheat Cultivars ◽  
Grain Yields ◽  
North West ◽  
The North ◽  
South Wales ◽  
Leaf Area Duration

The influence of variation in time of sowing on grain yield in five wheat cultivars has been studied in the North West Slopes of New South Wales over the period 1967 to 1971. Highest grain yields were obtained when wheat was sown at the end of June so as to flower at the end of the first week in October. Reductions in relative grain yield of 5 to 7 per cent were recorded for each week that sowing was delayed after the end of June, or 9 to 13.5 per cent for each week that flowering was delayed after the first week in October. Lower grain yields from late sown crops were associated with lower leaf area duration after flowering which could account for 69 per cent of the variation in grain yield. Lower grain yields in early sown crops were associated with lower ear numbers which could be ascribed in part to the influence of frosts.

Leaf analysis for pear: development of standards and the nutritional status of orchards in the Goulburn Valley and Murrumbidgee Irrigation Areas

1975 ◽  
Vol 15 (72) ◽  
pp. 129 ◽  
Author(s):  
den Ende B van ◽  
DR Leece
Keyword(s):  
Nutritional Status ◽  
New South ◽  
Yield Data ◽  
Leaf Analysis ◽  
South Wales ◽  
High Production ◽  
Pear Trees ◽  
Leaf Composition ◽  
Salt Toxicity ◽  
Good Agreement

Leaf composition standards for pear trees were formulated from the literature then evaluated in the Goulburn Valley, Victoria by surveying the leaf composition of high-production orchards for two seasons (1971-72 and 1972-73). Good agreement was found between the standards and orchard leaf composition although the calcium standards required slight amendment. A concurrent survey of orchards showing symptoms of salt toxicity showed that sodium and chloride levels previously considered safe were in fact toxic and the standards were amended accordingly. The revised standards were used to evaluate the nutritional status of young and older pear blocks in the Goulburn Valley and pear blocks in the Murrumbidgee Irrigation Areas (MIA), New South Wales. The findings for Goulburn Valley blocks were confirmed by multiple regression analysis of leaf composition and yield data.

Tolerances of wheat cultivars to pre-emergence herbicides

1985 ◽  
Vol 25 (4) ◽  
pp. 922 ◽  
Author(s):  
D Lemerle ◽  
AR Leys ◽  
RB Hinkley ◽  
JA Fisher
Keyword(s):  
Grain Yield ◽  
Spring Wheat ◽  
Yield Loss ◽  
New South ◽  
New South Wales ◽  
Yield Reduction ◽  
Wheat Cultivars ◽  
Yield Losses ◽  
South Wales

Twelve spring wheat cultivars were tested in southern New South Wales for their tolerances to the recommended rates and three times the recommended rates of trifluralin, pendimethalin, tri-allate and chlorsulfuron. Recommended rates of these herbicides did not affect the emergence or grain yield of any cultivar. However, differences between cultivars in their tolerances to trifluralin, pendimethalin and chlorsulfuron at three times the recommended rate were identified. The extent of the reduction in emergence and/or grain yield varied with herbicide and season, and there was also a herbicidexseason interaction. Durati, Songlen and Tincurrin were the most susceptible cultivars to trifluralin, and Teal was the most tolerant. Yield losses from trifluralin were more severe in 1979 than in 1980 or 1981. The differential between cultivars treated with pendimethalin was smaller and more variable; Tincurrin was the only cultivar with a yield reduction in more than one season. Durati, Songlen and Shortim were the only cultivars affected by chlorsulfuron. A reduction in crop emergence of a cultivar treated with trifluralin or pendimethalin did not correlate consistently with any grain yield loss, and reductions in emergence were always greater than yield loss.

Simulation of the effect of chilling injury and nitrogen supply on floret fertility and yield in rice

1994 ◽  
Vol 34 (7) ◽  
pp. 921 ◽  
Author(s):  
DC Godwin ◽  
WS Meyer ◽  
U Singh
Keyword(s):  
Management Practices ◽  
New South ◽  
Chilling Injury ◽  
New South Wales ◽  
Growth And Yield ◽  
Comprehensive Model ◽  
Night Time ◽  
Yield Data ◽  
South Wales ◽  
High Yields

Evidence exists that night temperatures <18�C immediately preceding flowering in rice crops can adversely affect floret fertility and, hence, yields. It has been suggested that sterility induced by low temperature is also influenced by floodwater depth and nitrogen (N) rate. In southern New South Wales, low night-time temperatures are believed to be a major constraint to the achievement of consistently high yields. The availability of a comprehensive model of rice growth and yield that is sensitive to this constraint would aid the development of better management practices. CERES RICE is a comprehensive model that simulates the phasic development of a rice crop, the growth of its leaves, stems, roots, and panicles, and their response to weather. It also simulates the water and N balances of the crop and the effects of stresses of water and N on the yield-forming processes. The model has been extensively tested in many rice-growing systems in both tropical and temperate environments. However, the original model was unable to simulate the level of chilling injury evident from yield data from southern New South Wales. This paper reports modifications made in the model to simulate these effects and the evaluation of the model in environments of low night temperature. Inclusion of the chilling injury effect greatly improved the accuracy of estimated yields from treatments in an extensive field experiment. However, additional testing with a wider range of data sets is needed to confirm the international applicability of the modifications.

Impact of legume 'break' crops on the yield and grain quality of wheat and relationship with soil mineral N and crop N content

2003 ◽  
Vol 54 (8) ◽  
pp. 777 ◽  
Author(s):  
J. Evans ◽  
G. Scott ◽  
D. Lemerle ◽  
A. Kaiser ◽  
B. Orchard ◽  
...  
Keyword(s):  
Green Manure ◽  
Soil Depth ◽  
New South ◽  
Wheat Yield ◽  
Grain Legumes ◽  
Grain Protein ◽  
Mineral N ◽  
Yield Increase ◽  
South Wales

The effect of annual 'break' crops on the yield and protein content of wheat was investigated over 3 seasons on a Red Kandasol on the south-western slopes of New South Wales. The 'break' crops included lupin and pea grown for grain, pea and vetch managed for silage, clovers managed for silage or hay, and vetch and clovers managed for green manuring. Wheat was sown for 2 years following the legume year, or canola and wheat followed the legumes. Averaged over 3 experiments the yields of first crop wheat following pea or vetch silage crops were comparable with those after grain pea. Yields following clover forage conservation crops or green manures exceeded those after grain pea by at least 0.41 t/ha; average yield increase after clover green manure was 0.93 t/ha. In one experiment, yields of second crop wheat were greater, by up to 0.37 t/ha, after forage conservation or green manure legume 'breaks' than after grain legumes. In 2 experiments, second crop wheat yields were greater after a first crop of canola than a first crop of wheat. Compared with continuous wheat yield, aggregate mean wheat yield increases were 3.5–4 t/ha following grain legumes, pea, and vetch silage crops, but 5.3–6.3 t/ha following clover forage conservation and green manure crops. However, the relative effects of legume treatments on wheat yield were significantly seasonally dependent. Yield and grain protein variation in wheat after legumes was significantly correlated with variation in mineral N at wheat establishment. However, in one experiment, yield was correlated only with variation in mineral N below the 20-cm soil depth, whereas protein was correlated only with variation in mineral N above the 20 cm soil depth. Yield increases in first crop wheat did not occur at the expense of grain protein.

Wheat response after temperate crop legumes in south-eastern Australia

1991 ◽  
Vol 42 (1) ◽  
pp. 31 ◽  
Author(s):  
J Evans ◽  
NA Fettell ◽  
DR Coventry ◽  
GE O'Connor ◽  
DN Walsgott ◽  
...  
Keyword(s):  
New South ◽  
Wheat Yield ◽  
Wheat Crop ◽  
First Year ◽  
Mineral N ◽  
Total N ◽  
Available N ◽  
Relative Contribution ◽  
South Wales ◽  
Eastern Australia

At 15 sites in the cereal belt of New South Wales and Victoria, wheat after lupin or pea produced more biomass and had a greater nitrogen (N) content than wheat after wheat or barley; on average these crops assimilated 36 kg N/ha more. The improved wheat yield after lupin averaged 0 . 9 t/ha and after pea 0.7 t/ha, increases of 44 and 32% respectively. The responses were variable with site, year and legume. Soil available N was increased by both lupin and pea and the levels of surface inorganic N measured at the maturity of first year crops was often related to N in wheat grown in the following year. Of two possible sources of additional N for wheat after legumes, namely mineral N conserved in soil by lupin or pea (up to 60 kg N/ha) and the total N added in the residues of these legumes (up to 152 kg N/ha), both were considered significant to the growth of a following wheat crop. Their relative contribution to explaining variance in wheat N is analysed, and it is suggested wheat may acquire up to 40 kg N/ha from legume stubbles. Non-legume break crops also increased subsequent wheat yield but this effect was not as great as the combined effect of added N and disease break attained with crop legumes.

Classification of wheat areas and prediction of yields in north-western New South Wales by repetitive Landsat data

1980 ◽  
Vol 31 (3) ◽  
pp. 449 ◽  
Author(s):  
KW Dawbin ◽  
JC Evans ◽  
MJ Duggin ◽  
EK Leggett
Keyword(s):  
New South ◽  
New South Wales ◽  
Wheat Yield ◽  
Multivariate Statistical ◽  
Wheat Growth ◽  
South Wales ◽  
Three Stages ◽  
Radiance Data ◽  
Vegetative Phases

Radiance data collected by Landsat were used to derive wheat production forecasts. Radiance data at three stages of wheat growth in 1976 for the Tamworth region of the New South Wales wheat-belt were analysed by multivariate statistical methods to discriminate between paddocks that had been sown with wheat and those that had not, and to relate radiance to wheat yield. A discriminant function was derived that classified the paddocks, and a regression equation was derived to predict yields of wheat paddocks. Although data were not available for the green vegetative phases of growth, intrinsic testing of classification and yield prediction indicated high accuracy, although extrinsic testing indicated that they were less accurate. Assuming that data are available in future seasons at the vegetative stages, Landsat has a great potential for improving wheat forecasts in Australia.

Seasonal variation in the value of subsoil water to wheat: simulation studies in southern New South Wales

2007 ◽  
Vol 58 (12) ◽  
pp. 1115 ◽  
Author(s):  
J. M. Lilley ◽  
J. A. Kirkegaard
Keyword(s):  
New South ◽  
New South Wales ◽  
Wheat Yield ◽  
Water Extraction ◽  
Yield Potential ◽  
Annual Rainfall ◽  
Wheat Crop ◽  
Subsoil Water ◽  
Mean Annual Rainfall ◽  
South Wales

Water stored deep in the soil profile is valuable to crop yield but its availability and conversion to grain vary with preceding management and seasonal rainfall distribution. We investigated the value of subsoil water to wheat on the Red Kandosol soils in southern New South Wales, Australia, using the APSIM Wheat model, carefully validated for the study area. Simulation treatments over 106 years of historic climate data involved a factorial combination of (1) a preceding crop of either lucerne (Dry treatment) or a low-yielding wheat crop (Wet treatment) and (2) restriction of wheat root depth to either 1.2 or 1.8 m. Root access to the subsoil (1.2–1.8 m) increased wheat yield by an average of 0.6 and 0.3 t/ha for the Wet and Dry treatments, respectively, at Cootamundra (mean annual rainfall 624 mm) and by 0.5 and 0.1 t/ha at Ardlethan (mean annual rainfall 484 mm). The differences were principally related to the frequency with which the subsoil failed to wet up, which occurred in 8% and 39% of years at Cootamundra in Wet and Dry treatments, respectively, but in 21% and 79% of years at Ardlethan. In seasons where water from the subsoil was used, the mean value of the water for grain yield, expressed as marginal water-use efficiency (MWUE), was 30–36 kg/ha.mm at both sites. High MWUE (>60 kg/ha.mm) generally occurred in seasons of above-average rainfall when subsoil water facilitated extra post-anthesis water extraction, including that from upper soil layers, to realise the high yield potential. Low MWUE (<10 kg/ha.mm) occurred when re-translocation of pre-anthesis assimilate to grain in the 1.2 m treatment compensated for reduced subsoil water extraction and no yield difference between 1.2 and 1.8 m treatments was observed. Counter-intuitively, the results suggest that subsoil water will be of more value in higher rainfall environments due to its more frequent occurrence, and in above-average seasons due to more efficient conversion to grain.

Resistance of durum wheat cultivars to black point caused by Alternaria alternata

1980 ◽  
Vol 31 (6) ◽  
pp. 1097 ◽  
Author(s):  
RJ Southwell ◽  
PTW Wong ◽  
JF Brown
Keyword(s):  
Durum Wheat ◽  
Alternaria Alternata ◽  
New South ◽  
New South Wales ◽  
Wheat Cultivars ◽  
Black Point ◽  
South Wales

Resistance of durum wheat cultivars to black point caused by Alternaria alternata was evaluated in the field in northern New South Wales. The cultivars tested showed a range of infection levels. The most susceptible cultivars were Duramba and Gaza, while those showing the greatest resistance were Wandell, Wascana and aus 15350.

The development of lucerne with resistance to root rot in poorly aerated soils

1978 ◽  
Vol 18 (92) ◽  
pp. 434 ◽  
Author(s):  
VE Rogers ◽  
JAG Irwin ◽  
G Stovold
Keyword(s):  
Root Rot ◽  
New South ◽  
New South Wales ◽  
Mass Selection ◽  
Infested Soil ◽  
Yield Data ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
South Wales ◽  
Disease Free

Three cycles of recurrent mass selection in the field increased the level of resistance of lucerne (Medicago sativa) to Phytophthora root rot in irrigated heavy clay soil at Deniliquin, New South Wales. The breeding stocks were derived from Siro Peruvian and Lahontan. In each cycle between 45 and 80 vigorous, disease free plants were selected from soil naturally infested with Phytophthora megasperma var. sojae, and allowed to interpollinate. Yield data and ratings for root rot were obtained for half-sib families sown in rows. Progeny in cycle 1 were inoculated by isolates of P. megasperma from both New South Wales and Queensland, and there was substantial agreement between both sources in ratings for disease. In the third cycle of selection, progeny had a disease rating of 1.4 when inoculated with Queensland isolates of P. megasperma, compared with 3.6 and 4.1 for Hunter River and Siro Peruvian respectively (plants scored 1 or 2 considered resistant; 3, 4 or 5 susceptible). In a field trial, the percentage of disease-free plants after eight months of growth in infested soil was: cycle 3 selections, 44.4; Hunter River, 9.9; Siro Peruvian, 12.0. Cumulative dry matter production of the selections during that time was twice that of Hunter River.

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