scholarly journals Estimating gain by use of a classic selection index under multicollinearity in wheat (Triticum aestivum)

1999 ◽  
Vol 22 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Samuel Pereira de Carvalho ◽  
Cosme Damião Cruz ◽  
Claudio Guilherme Portela de Carvalho

It was shown that the classic selection index, under multicollinearity, could not give simultaneous gains for wheat grain production and its primary components. This was due to the instability and, consequently, low precision of the coefficient index estimates. A modification of the prediction process of the index was proposed to avoid the adverse effects of multicollinearity, adopting a procedure based on ridge regression theory. The modified classic selection index, or ridge index, gave more statistically viable index coefficient estimates and gains for all of the characters evaluated. However, lower gains for number of grains per spike and grain yield were obtained, when compared to those obtained with selection for grain yield.

2019 ◽  
Vol 132 (6) ◽  
pp. 1705-1720 ◽  
Author(s):  
Jin Sun ◽  
Jesse A. Poland ◽  
Suchismita Mondal ◽  
José Crossa ◽  
Philomin Juliana ◽  
...  

Euphytica ◽  
2010 ◽  
Vol 177 (2) ◽  
pp. 253-266 ◽  
Author(s):  
Todd A. Reid ◽  
Rong-Cai Yang ◽  
Donald F. Salmon ◽  
Alireza Navabi ◽  
D. Spaner

2009 ◽  
Vol 60 (6) ◽  
pp. 566 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland

Canola (oilseed rape, Brassica napus L.) is now grown in rotation with spring wheat (Triticum aestivum L.) on the predominantly sandy soils of south-western Australia. For both crop species, fertiliser nitrogen (N) and phosphorus (P) need to be applied for profitable grain production. The fertiliser N requirements have been determined separately for canola or wheat when adequate P was applied. By contrast, the fertiliser P requirements of the 2 species have been compared in the same experiment when adequate N was applied and showed that canola consistently required ~25–60% less P than wheat to produce 90% of the maximum grain yield. We report results of a field experiment conducted at 7 sites from 2000 to 2003 in the region to compare grain yield responses of canola and wheat to application of N and P in the same experiment. Four levels of N (0–138 kg N/ha as urea [46% N]) and 6 levels of P (0–40 kg P/ha as superphosphate [9.1%P]) were applied. Significant grain yield responses to applied N and P occurred for both crop species at all sites of the experiment, and the N × P interaction for grain production was always significant. To produce 90% of the maximum grain yield, canola required ~40% more N (range 16–75%) than wheat, and ~25% less P (range 12–43%) than wheat. For both crop species at 7 sites, applying increasing levels of N had no significant effect on the level of P required for 90% of maximum grain yield, although at 1 site the level of P required to achieve the target yield for both crop species when no N was applied (nil-N treatment) was significantly lower than for the other 3 treatments treated with N. For both crop species at all 7 sites, applying increasing levels of P increased the level of N required for 90% of the maximum grain yield. Fertiliser P had no significant effect on protein concentration in canola and wheat grain, and oil concentration in canola grain. As found in previous studies, application of increasing levels of N decreased oil concentration while increasing protein concentration in canola grain, and increased protein concentration in wheat grain. The N × P interaction was not significant for protein or oil concentration in grain. Protein concentrations in canola grain were about double those found in wheat grain.


1997 ◽  
Vol 11 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Randall S. Currie ◽  
Mosad A. El-Hamid

A three-year field study in west-central Kansas investigated the effects of combinations of spray carrier, nonionic surfactant (NIS), triasulfuron, and/or 2,4-D on winter wheat foliar injury and grain yield. Herbicides applied in water without NIS caused little or no foliar injury in two of three years. Urea-ammonium nitrate (UAN) at 112 L/ha (40 kg N/ha) alone or as a carrier for herbicides caused moderate to severe foliar injury in all three years. Adding NIS to UAN spray solutions increased foliar injury, especially with the tank mixture of triasulfuron + 2,4-D. Effects of triasulfuron + NIS or 2,4-D applied in UAN were additive. Foliar injury was related inversely to temperature following application. Foliar injury was most evident 4 to 7 d after application and disappeared within 2 to 3 wk. Diluting UAN 50% with water lessened foliar injury in two of three years, especially in the presence of NIS, regardless of whether herbicides were in the spray solution. Treatments did not reduce wheat grain yield in any year despite estimates of up to 53% foliar injury one year.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2047
Author(s):  
Matthew R. Ryan ◽  
Sandra Wayman ◽  
Christopher J. Pelzer ◽  
Caitlin A. Peterson ◽  
Uriel D. Menalled ◽  
...  

Mulch from cover crops can effectively suppress weeds in organic corn (Zea mays L.) and soybean (Glycine max L.) as part of cover crop-based rotational no-till systems, but little is known about the feasibility of using mulch to suppress weeds in organic winter small grain crops. A field experiment was conducted in central NY, USA, to quantify winter wheat (Triticum aestivum L.) seedling emergence, weed and crop biomass production, and wheat grain yield across a gradient of mulch biomass. Winter wheat seedling density showed an asymptotic relationship with mulch biomass, with no effect at low rates and a gradual decrease from moderate to high rates of mulch. Selective suppression of weed biomass but not wheat biomass was observed, and wheat grain yield was not reduced at the highest level of mulch (9000 kg ha−1). Results indicate that organic winter wheat can be no-till planted in systems that use mulch for weed suppression. Future research should explore wheat tolerance to mulch under different conditions, and the potential of no-till planting wheat directly into rolled-crimped cover crops.


1970 ◽  
Vol 50 (3) ◽  
pp. 267-276 ◽  
Author(s):  
J. PESEK ◽  
R. J. BAKER

Results of a genetic study of four quantitative characters in a cross of two cultivars of Triticum aestivum L. em Thell. indicated that heritability of yield was lower than the heritabilities of maturity and height and that interactions between genotypic effects and year environmental effects were nonsignificant. The modified selection index method, based upon desired genetic gains rather than relative economic weights of traits, is explained in detail and applied to selection for maturity, height and yield from a hybrid population of wheat. The methods and problems of using index selection in self-pollinated species are discussed.


1993 ◽  
Vol 73 (3) ◽  
pp. 713-719 ◽  
Author(s):  
A. P. Moulin ◽  
H. J. Beckie

The EPIC and CERES simulation models were used to predict spring wheat (Triticum aestivum L.) grain yield from long-term (1960–1989) crop rotations at Melfort, Saskatchewan. Although both models simulated annual yields poorly, they predicted long-term mean yields with reasonable accuracy. Key words: Spring wheat, Triticum aestivum L., yield, models, CERES, EPIC


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