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Adapted models for the analysis of combining ability of varieties in partial diallel crosses

Isaias O. Geraldi; Jose B. de Miranda-Filho

Departamento de Genética, ESALQ-USP, Caixa Postal 83, 13400 Piracicaba, SP, Brasil. Send correspondence to I.O.G.

ABSTRACT

Two models were suggested for the analysis of combining ability of varieties when crossed in the partial diallel scheme with the parents included. Model `partial-ST' was based on the concepts of Sprague and Tatum and the total variation was partitioned into varieties, crosses, and varieties vs crosses and the variation due to crosses was also partitioned into general (g<sub>i</sub>) and specific (s<sub>ij</sub>) combining ability. Thus, the adapted model for crosses was: Y<sub>ij</sub> = u + g<sub>i</sub> + g<sub>j</sub> + <sup>s</sup>i) + where Y<sub>ij</sub> is the mean of the cross between the ith variety of Group (1) and the jth variety of Group (2), and g's and s<sub>ij</sub> are general and specific combining ability, respectively.
The model designated as `partial-G2' was based on Griffing's method 2 and was expressed by: Y_ij = u + 2 [d(t) + d₍₂₎] + g. + g. + s_ij + éij,where ^d(1) and d₍₂₎ are deviations due to differ ences between the two groups of varieties, and the other terms are defined for the `partial-ST' model. Formulas were given for the estimation of effects and for obtaining sums of squares in the analysis of variance for both models. An example was given for illustration and some comparisons were made among models.

Keywords: combining; varieties; diallel; crosses.

REFERENCES

Anunciação Filho, C.J. (1976). Capacidade de combinação entre compostos e híbridos simples de milho (Zea mays L.). Masters Thesis, ESALQ-USP, Piracicaba, SP, 91 pp.

Gardner, C.O. and Eberhart, S.A. (1966). Analysis and interpretation of the variety cross diallel and related populations. Biometrics 22: 439-452.

Griffing, B. (1956). Concept of general and specific combining ability in relation to diallel crossing systems. Aust. J. Biol. Sci. 9: 463-493.

Miranda Filho, J.B. and Vencovsky, R. (1984). Analysis of diallel crosses among open-pollinated varieties óf maize (Zea mays L.). Maydica 29: 217-234.

Miranda Filho, J.B. and Geraldi, I.O. (1984). An adapted model for the analysis of partial diallel crosses. Braz. J. Genet. 7: 677-688.

Sprague, G.F. and Tatum, L.A. (1942). General vs. specific combining ability in single crosses of corn. J. Am. Soc. Agron. 34: 923-932.

Vencovsky, R. (1978). Herança Quantitativa. In: Melhoramento e Produção de Milho no Brasil. (Paterniani, E., ed.). Edição da Fundação Cargill, pp. 122-201.