Control Balanced Designs Involving Sequences of Treatments

Designs involving sequences of treatments for test vs. control comparisons are suitable for research in which each experimental unit receives treatments over time in order to compare several test treatments to one (or more) control treatment(s). These designs can be advantageously used in screening experiments and bioequivalence trials. Three series of such designs are constructed in incomplete sequences wherein the first class of designs is variance balanced while the other two classes of designs are partially variance balanced for test versus test comparisons of both direct and residual effects of treatments

Nonparametric Methods for Data Analysis

A parametric test specifies certain conditions about the distribution of responses in the population from which the research sample was drawn. The meaningfulness of the results of a parametric test depends on the validity of these assumptions. A nonparametric test is based on a model that specifies very general conditions and none regarding the specific form of the distribution from which the sample was drawn. Hence nonparametric tests are also known as distribution free tests. Certain assumptions are associated with most nonparametric statistical tests, but these are fewer and weaker than those of parametric tests

Neighbor Balanced Block Designs for Two Factors

The concept of Neighbor Balanced Block (NBB) designs is defined for the experimental situation where the treatments are combinations of levels of two factors and only one of the factors exhibits a neighbor effect. Methods of constructing complete NBB designs for two factors in a plot that is strongly neighbor balanced for one factor are obtained. These designs are variance balanced for estimating the direct effects of contrasts pertaining to combinations of levels of both the factors. An incomplete NBB design for two factors is also presented and is found to be partially variance balanced with three associate classes

SAS MACRO for Generation of Partial Tetra-allele Cross Design using MOLS

Tetra-allele cross often referred as four-way cross or double cross or four-line cross are those type of mating designs in which every cross is obtained by mating amongst four inbred lines. A tetra-allele cross can be obtained by crossing the resultant of two unrelated diallel crosses

Resolvable mating-environmental designs for partial triallel cross experiments

Triallel crosses can be readily exploited as breeding tool for developing commercial hybrids with traits of genetical and commercial importance by acquiring information on specific combining ability effects along with general combining ability effects if the experimentation size is reduced to an economical extent. In this paper, methods of constructing designs involving partial triallel crosses in smaller blocks using different types of lattice designs have been introduced. The designs have low degree of fractionation, which suggests their utility when there is a resource crunch. Canonical efficiency factor of these designs relative to an orthogonal design with same number of lines, assuming constant error variance for both situations, is high indicating that adoption of these designs for the trials could bring about improvement as the recommendations from the experiment will be associated with a high precision

Web based Generation of Polycross Designs (webPD)

Careful choice of parental lines and efficient mating designs form the backbone to a successful plant breeding programme. Objectives of the study, nature of genotypes, pollination type, space, cost, heterogeneity present in the field, wind direction, etc. are some of the deciding factors of a mating design. For wind pollinated species, a group of selected genotypes are to be arranged in isolated blocks/rows and columns such that each genotype gets an equal chance of pollinating, or being pollinated by, any of the others. Different types of designs for polycross trials are conducted for different situations like octa neighbour balanced polycross designs, designs for directional wind system, neighbour restricted polycross designs, etc. For ready referencing and potential use of these designs, online software for generation of these designs is highly desirable. In this paper, the development of a web solution for generation of different classes of polycross designs based on client–server architecture has been discussed. The software webPD is easily accessible at any time from any arbitrary platform throughout the globe through the use of internet. This software provides freely available solution for the researchers, breeders and students working in this area

Designs for sensory trials involving foods of animal origin

Sensory quality is a basic factor that influences consumers while purchasing processed food of animal origin. Experimental designs will prove an effective tool in establishing a sensory fact in trials involving animal produce. To draw valid conclusion from a study, it is important to eliminate or minimize all sources of error and control all factors that may influence the inference. Hence, in addition to the potential sources associated with the preparation of the test products, variability due to measurement or assessment process, order effects, carryover effects and assessor fatigue are to be considered. When there are a large number of products, two operational constraints limit the choice of experimental designs viz., assessor constraint that sets a maximum number of products that an assessor can evaluate within a session before onset of sensory fatigue and preparation constraint that limits the number of products that can be prepared for a given session without loss of experimental control. Hence, it is many times necessary to split sensory evaluation into two sessions. Here, a general method to construct designs for sensory trials in two sessions, which are balanced for carry over effects within session, is proposed. The design is resolvable in the sense that panelist would get an opportunity to evaluate every product exactly once at the end of both the sessions

Robust designs involving partial triallel crosses for breeding experiments

Obtaining information regarding general combining ability (Gca) and specific combining ability (sca) effects can be the major objective of a breeding programme to release new hybrids with enhanced genetic potential. This study included designs involving partial triallel crosses as they, being genetically more viable and consistent performers, involve lesser number of crosses leading to a lower degree of fractionation. An optimal or efficient design for triallel cross experiment may become disconnected and inefficient if the underlying assumptions are not fulfilled due to a missing observation pertaining to a cross. The robustness of designs against missing observation using connectedness and efficiency criteria has been studied both under unblocked and blocked situations. A list of efficient robust designs for triallel cross experiments has been tabulated for both unblocked and blocked situation. Programs have been written in SAS [PROC IML] software for computing efficiency factor of the designs involving triallel crosses for estimating Gca effects to investigate the robustness of designs against missing observation by calculating the efficiency factor

Neighbour Balanced Designs for Diallel Cross Experiments

This paper deals with obtaining series of block designs for complete and partial diallel cross experiments balanced for neighbour effects. Two series of Neighbour Balanced Block (NBB) designs for diallel cross in complete blocks and two series of NBB for diallel cross in incomplete blocks have been obtained. A catalogue of designs for number of lines ≤ 20 has been prepared listing the parameters of the designs

Package ‘PolycrossDesigns’

A polycross is the pollination by natural hybridization of a group of genotypes, generally selected, grown in isolation from other compatible genotypes in such a way to promote random open pollination. A particular practical application of the polycross method occurs in the production of a synthetic variety resulting from cross-pollinated plants. Laying out these experiments in appropriate designs, known as polycross designs, would not only save experimental resources but also gather more information from the experiment. Different experimental situations may arise in polycross nurseries which may be requiring different polycross designs (Varghese et. al. (2015) . `` Experimental designs for open pollination in polycross trials''). This package contains a function named PD() which generates nine types of polycross designs suitable for various experimental situations