Contribution of Additive and Dominance Effects on Agronomical and Nutritional Traits, and Multivariate Selection on Urochloa spp. Hybrids.
2018
MATIAS, F. I. | BARRIOS, S. C. L. | BEARARI, L. M. | MEIRELES, K. G. X. | MATEUS, R. G. | AMARAL, P. N. C. do | ALVES, G. F. | VALLE, C. B. do | FRITSCHE-NETO, R. | FILIPE INÁCIO MATIAS, Universidade de São PAULO - USP/Escola Superior de Agricultura Luiz de Queiroz - ESALQ/Departamento de Genética; SANZIO CARVALHO LIMA BARRIOS, CNPGC; LUCAS MARTINS BEARARI, Universidade Estadual de Mato Grosso do Sul - UEMS; KAREM GUIMARAES XAVIER MEIRELES, CNPGC; ROGÉRIO GONÇALVES MATEUS, Universidade Estadual de Mato Grosso do Sul - UEMS; PEDRO NELSON CESAR DO AMARAL, Universidade Estadual de Mato Grosso do Sul - UEMS; GEOVANI FERREIRA ALVES, Universidade Federal de Mato Grosso do Sul - UFMS; CACILDA BORGES DO VALLE, CNPGC; ROBERTO FRITSCHE-NETO, Universidade de São PAULO - USP/Escola Superior de Agricultura Luiz de Queiroz - ESALQ/Departamento de Genética.
A tropical forage breeding program contains several peculiarities, especially when it involves polyploid species and facultative apomixis. Urochloa spp. are excellent perennial forages, and the identification of superior genotypes depends on the selection of many characteristics under complex genetic control, with high cost and time-consuming evaluation. Therefore, the use of tools such as multivariate analysis and diallel analyses could contribute to improving the efficiency of breeding programs. Thus, the objectives were to estimate (i) the contribution of additive and nonadditive effects on agronomical and nutritional traits in a population of interspecific hybrids of Urochloa spp., originated from a partial diallel between five apomictic and four sexual parents, and (ii) the accuracy of multivariate index selection efficiency. Genetic variability was detected between the parents, crosses, and hybrids for all the traits. There was no clear trend of the importance of the additive and nonadditive genetic effects on agronomical and nutritional traits. Furthermore, the predominant component of genetic variance changed depending on the characteristic. Moreover, there was no parent or cross that was outstanding for all traits simultaneously, showing the high variability generated from these crosses. The Mulamba and Mock index associated with principal components analysis allowed a more significant gain only for agronomic characteristics. However, the per se index, at the univariate level, promoted a more balanced response to selection for all traits.
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