IncorporaÃÃo da informaÃÃo de parentesco no mÃtodo genealÃgico pelo enfoque de modelos mistos / Using relationship information from pedigree method on mixed model estimation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

In the pedigree method it is usually spent an additional effort for recording the genealogies along the generations, that have been attributed little usefulness. This study aimed to evaluate the efficiency of the pedigree method considering the use of relationship among progenies and to compare its performance with the bulk method by computer simulation and in field experiments. It was assumed a genetic model with 20 segregating loci with alelic frequency equal to 0.5. All loci were assumed to have equal effect, no epistasis and no linkage. For the appraised configurations it was considered values of broad sense heritability at the progenies level of 10%, 25%, 50% and 75% and average level of dominance of 0.0, 0.5 and 1.0. It was evaluated 256 F4:5 progenies in 1000 simulated experiments for each configuration and selection method. In the field experiments 256 F4:5 progenies (in the rainy season of 2004/05) and 256 F4:6 (in the dry season of 2005) from the pedigree and bulk methods were evaluated. The common bean segregating population was obtained from the crossing between parents BRS Talismà and BRS Valente. The analyses of the simulated and field data were accomplished by the mixed model approach. The pedigreeâs data were analyzed according of two models: ignoring and considering the additive genetic relationship among progenies. For the bulk method the analysis was accomplished considering the progenies as not related. The appraised selection criteria were the progenies average and the best linear unbiased prediction (BLUP) considering the relationship, denoted by BLUPA and in the relationship absence, denoted by BLUP. Dominance had little influence on the simulation results for both selection methods. The BLUPA was more efficient than the average in all studied configurations, resulting in the best ranking of the progenies. For the field experiments there was significantly no null genetic variation among the progenies for grain yield and plant stature in both methods of conduction of the segregating populations. It can be inferred that the pedigree selection take account the genetic similarity among progenies (BLUPA) had selections gain greater than the same method ignoring this pedigree information (BLUP). This advantage may compensate the additional effort spent obtaining pedigree records, mainly for traits of low heritability. The pedigree and bulk methods, in the simulated conditions, were equally efficient for obtaining superior genotypes, however when the progenies relationship was considered the pedigree method was slightly superior to bulk method.

ASSUNTO(S)

pedigree pedigree simulaÃÃo simulation agronomia melhoramento genÃtico vegetal plant breeding blup blup

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