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EN
One of the most important characteristics in determining the dendrometrical properties of a stand is the annual height increment of the trees. On the basis of these increments, natural phases of the trees’ life are defined. In the present study the data concern the height increments of the main trunk of 25-year-old Scots pine, as well as simulated data. Our research deals with the application of longitudinal data analysis. This analysis is usually used when measurements are taken at the same treatments at different time points. The calculations performed provide answers to the question of which annual height increments differ.
EN
A method of discriminant variable determination was used to visualize the division of oak trees into Kraft classes. Usual discriminant variables and several types of kernel discriminant variables were studied. For this purpose the traits of oak (Quercus L.) trees, measured on standing trees, were used. These traits included height of tree, breast height diameter and crown projection area. The use of the Gaussian kernel and modified Gaussian kernel enabled the clearest division into Kraft classes. In particular, the latter method proved to be the most effective.
EN
In studies of organic soil degradation and transformation, alongside the conventional methods used in soil science, an increase in the importance of advanced statistical methods can be observed. In this study some multivariate statistical methods were applied in an investigation of organic soil transformation in the central Sudetes. Andrews curves, linear and kernel discriminant variable analysis and cluster analysis were used. The similarities among peatland soils and their layers were determined. It can be stated that the application of statistical methods in soil science research related to organic soil transformation is a valuable tool. The use of various statistical methods (such as Andrews curves, linear and kernel discriminant variables and cluster analysis) can with high probability confirm earlier laboratory or field observations. This is particularly justified in the case of organic soils derived from varied geobotanical peat materials, different types of peatlands and water supply types, which impact the primary properties of the soil.
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The influence of weather conditions on annual height increments of Scots pine

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EN
Annual height increments are a very important characteristic of Scots pine. They have a direct effect on the determination of the dendrometric properties of a stand, such as volume increment. In the present study the data concern height increments of the main shoot in selected age classes of trees (age 72 to 92 years). A relationship is determined between the values of the increments and meteorological conditions such as temperature, precipitation and sunshine. On the basis of lasso regression analysis, precipitation in the year preceding the incremental season was shown to have the greatest effect on height increments of Scots pine.
EN
In breeding experiments conducted prior to tests connected with the registration of new breeding lines of crops, pre-preliminary and preliminary trials are carried out. In this study a comparison was made among some models of analysis of variance, in relation to the selection of new breeding lines of spring barley (Hordeum vulgare L.). The aim is to determine whether the choice of model of analysis of variance may influence the choice of tested breeding lines. The trait considered was the yield in two years of trials. A more comprehensive analysis of variance model was found to be superior. It was also found that the results of analyses performed using average measurements for lines significantly differ from those obtained on the basis of all measurements. It was concluded that the type of ANOVA model used may have an impact on inferences about breeding lines. Moreover, a lack of stability in the yields of tested lines was revealed, implying the necessity of several years of trials.
EN
An analysis is made of the possibility of reducing numbers of measurements in DUS (distinctness, uniformity and stability) trials on varieties of white mustard and oilseed rape, based on the results of DUS trials performed in the years 2005–2009 by the Research Centre for Cultivar Testing. It is shown that, when decisions are taken after three years of testing, it is possible to decrease the number of measurements by 50%, with the decisions practically unchanged for both considered species. For so-called early decisions (after two years of testing) the distinctness decisions are again practically the same for full and reduced data, although the decisions concerning uniformity differ significantly. This means that the number of measurements can be reduced only in cases where DUS testing is continued for three years.
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EN
The differences between individual breeding lines of spring barley and a control variety were tested in terms of several measured (continuous) and qualitative traits. The impact of the qualitative traits (diseases) on the quantitative traits, especially yield, was assessed on the basis of the significance of differences for both qualitative traits and yield. Depending on the type of trait, either a logistic model or analysis of variance was used as a statistical tool. The statistically significant differences between some breeding lines and the control variety were shown. It was observed that in fodder barley both infection by mildew and lodging influenced yield. The results of analyses obtained in the so-called pre-preliminary trials and preliminary trials were different. This fact confirmed the necessity of repeating trials over several years.
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A remark on genotype selection in plant breeding projects

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EN
One of the main problems in plant breeding is the selection of the best genotypes. Most often the selection is made using yield as a main trait of continuous type, and ignoring the other traits of discrete type. Here, a simple procedure is proposed for dealing with the selection problem using not only the yield, but also an auxiliary discrete trait. The method is based on transforming the continuous variable into a discrete one and testing the dependence of variables with the use of contingency tables. The procedure is illustrated by a real unreplicated experiment with winter wheat.
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