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Researcher Aswal, Kuldeep
Advisor Jagg, Seema
Source KrishiKosh-Indian National Agricultural Research System
Content type Text
Educational Degree Master of Science (M.Sc.)
File Format PDF
Language English
Subject Domain (in DDC) Technology ♦ Agriculture & related technologies ♦ Animal husbandry
Subject Keyword Designs For Diallel Cross Experiments Incorporating Neighbour Effects ♦ Agricultural Statistics and Informatics
Abstract Plant breeding programmes are conducted to study genetic properties of inbred lines involved in the crosses in order to develop improved crop varieties. Through these programmes, combining capacities of the lines are studied. Diallel cross plans are the most commonly used plans to study the combining abilities of the lines which includes the general combining ability (gca) and specific combining ability (sca). The gca of an inbred line is the average performance of the hybrids which this line produces with other lines chosen from a random mating population and the sca refers to a pair of inbred lines involved in the cross. Generally, in breeding experiments, where the treatments are the crosses that are laid out in block design setup, it is assumed that the observations from each plot receiving a cross is not affected by any other sources. However, there may arise neighbour effects from the crosses in the adjacent neighbouring plots in a block i.e., the response on a given plot is affected by the crosses on the neighbouring plots. For such situations, neighbour balanced designs are used. A block design for diallel crosses is said to be neighbour balanced if each line has all the crosses appearing as neighbours equal number of times. This study deals with obtaining block designs for complete and partial diallel cross experiments balanced for neighbour effects. Series of complete and incomplete block designs for complete diallel crosses have been obtained and are found to be variance balanced. Another series of block designs are obtained for partial diallel crosses and the designs are found to be partially variance balanced depending on the association scheme used for obtaining partial diallel crosses which are group divisible, triangular and circular association schemes in this study. A SAS macro has been developed that generates complete block designs for complete diallel crosses balanced for neighbour effects. A catalogue of designs for number of lines ≤ 20 has been prepared listing the parameters of the designs. SAS code using PROC IML for generating the information matrix for diallel cross incorporating neighbour effects has been developed. Incorporating neighbour effects into the model for diallel cross results in more precise estimation of gca effects.
Educational Use Research
Education Level UG and PG
Learning Resource Type Thesis
Size (in Bytes) 2.99 MB