What is diallel design?
The diallel mating design generally estimates the variation of quantitative characters in the genetic components like assessment of plant seed quality. The estimation is also performed to deduce the combining ability of the different inbred lines which participate in the different crosses taken into consideration.
What is diallel analysis?
Diallel cross refers to mating of selected parents in all possible combinations and evaluation of a set of diallel crosses is known as diallel analysis. Diallel is a Greek word and introduced by Schmidt in 1919.
What is full diallel?
In a full diallel, all parents are crossed to make hybrids in all possible combinations. Variations include half diallels with and without parents, omitting reciprocal crosses. Full diallels require twice as many crosses and entries in experiments, but allow for testing for maternal and paternal effects.
What is diallel selective mating?
The diallel selective mating system involves a planning phase and an implementation phase. The latter has four stages: a basic parent series of crosses (1) which set up the F1. diallel series of crosses (2) which when composited form P2; spaced P2 and subsequent P3, etc.
How diallel analysis is helpful for genetic studies?
Diallel crosses are also frequently used in genetic studies for determining mode of inheritance of the examined trait, as well as the number of genes that control the trait and gene effects.
How does marker assisted selection work?
Marker-assisted breeding uses DNA markers associated with desirable traits to select a plant or animal for inclusion in a breeding program early in its development. This approach dramatically reduces the time required to identify varieties or breeds which express the desired trait in a breeding program.
What is general combining ability?
General combining ability (GCA) is directly related to the breeding value of a parent and is associated with additive genetic effects, while specific combining ability (SCA) is the relative performance of a cross that is associated with non-additive gene action, predominantly contributed by dominance, epistasis, or …
What is partial diallel?
When the number of parents increases then it is not possible to handle these large number of crosses. In such cases we use partial diallel crosses in which we take a sample of crosses among all crosses in such a way that each parent is involved in crosses equal number of times(s).
What is partial diallel cross?
The partial diallel is one of many variations of the diallel (Griffing, 1956; Kempthorne and Curnow, 1961; Gardner and Eberhart, 1966) and consists of crosses among two parent groups. This mating system, also called experiment II, design II and factorial design, was proposed by Comstock and Robinson (1948, 1952).
What are the advantages of marker assisted breeding?
Marker-assisted selection may greatly increase the efficiency and effectiveness for breeding compared to conventional breeding. The fundamental advantages of MAS compared to conventional phenotypic selection are: Simpler compared to phenotypic screening. Selection may be carried out at seedling stage.
What is the difference between RAPD and SSR markers?
SSR detects the allelic variation by way of repeat numbers with in a locus and one pair of SSR primer deals with one locus (Weising et al., 1992) where as RAPD detects both allelic and locus variations in a single assay and deals with insertions, deletions, point mutations which influence the base sequence of primer …
What is GCA general combining ability?
What is diallel mating design?
Diallel mating design is used to evaluate several inbred lines in terms of combining ability variances and effects. Diallel cross refers to mating of selected parents in all possible combinations and evaluation of a set of diallel crosses is known as diallel analysis.
What are the current issues in Diallel analysis?
Some issues which evidently remain as areas of contention in diallel analysis are reveiwed. In the estimation of genetic variance components for an ancestral reference population in equilibrium, analysis should be applied to F1 data only, and proceed as for a random effects model.
What is a diallel cross?
Diallel cross: in a diallel cross, all pairwise hybridizations among the parents are made in single cross combinations. Diallels can be “complete” or “full” where crosses are made in both directions, that is, including reciprocal crosses, as well as self-pollinations of parents.
What is Hayman’s approach of Diallel analysis?
In the hayman’s approach of diallel analysis a graph is drawn with the help of variances of arrays (Vr) and covariances between parents and their offspring (Wr). This graph is known as Vr-Wr graph. Array: The array refers to the crosses in which a particular parent is common. Construction of Vr-Wr Graph: