The parametric restrictions of the Griffing diallel analysis model: combining ability analysis

Abstract

It was studied the parametric restrictions of the diallel analysis model of Griffing, method 2 (parents and F 1 generations) and model 1 (fixed), in order to address the questions: i) does the statistical model need to be restricted? ii) do the restrictions satisfy the genetic parameter values? and iii) do they make the analysis and interpretation easier? Objectively, these questions can be answered as: i) yes, ii) not all of them, and iii) the analysis is easier, but the interpretation is the same as in the model with restrictions that satisfy the parameter values. The main conclusions were that: the statistical models for combining ability analysis are necessarily restricted; in the Griffing model

Analysis of general and specific combining abilities of popcorn populations, including selfed parents

“…Therefore, the GCA and SCA effects should be considered in the selection of populations for hybrid production and for reciprocal recurrent selection programs. In addition to being indicators of the divergence of each population compared to the diallel parents, the SCA effects of a population with itself allow assessment of the predominant direction of the deviations due to dominance (Cruz and Vencovsky, 1989;Viana, 2000b). …”

“…selfed parental populations. The phenotypic means in the diallel table can be defined as follows (Viana, 2000b) where Y jj , Y jj' and Y jjF are, respectively, the means of the jth population, of the hybrid between the jth and j'th populations, and of the n times selfed jth population (j, j' = 1, ..., N);…”

Genetic Analysis of Tomato Fruit Ripening at Polypeptide Profiles Level through Quantitative and Multivariate Approaches

“…In this sense, significant and positive General Combining Abilities could be assigned to ToUNR8 and ToUNR18, while significant and negative ones could be assigned to ToUNR1 and ToUNR9 [29]. Also, significant and positive Specific Combining Ability could be assigned to H(ToUNR1 × ToUNR9) and significant and negative one to H(ToUNR15 × ToUNR9).…”

Genetic components of combining ability in a complete diallel

“…If the parents are inbred or pure lines, the greatest GCA effect is related to the line of the largest number of genes that increase the expression of the trait and, consequently, the greatest number of positive differences between its gene frequency and the mean frequency of the lines involved in the diallel (Viana 2000).…”