Full text in pdf format

Comparison of gains from selection among corn progenies, based on DIFFERENT CRITERIA^*

Cosme Damião Cruz^I; Roland Vencovsky^II; Sebastião de Oliveira e Silva^III; Geraldo Antonio Tosello^II

^IDepartamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brasil. Send correspondence to C.D.C.
^IIDepartamento de Genética, ESALQ/USP, Caixa Postal 83, 13418-900 Piracicaba, SP, Brasil
^IIIEMBRAPA/Centro Nacional de Pesquisa de Mandioca e Fruticultura (CNPMF), Caixa Postal 007, 44380-000 Cruz das Almas, BA, Brasil

ABSTRACT

A comparison was made of expected gains from selection among full-sib families of com, assuming direct selection for each trait and simultaneous selection, based on the following indices: a) classic; b) base; c) with desired gains as weights; d) free of weights and e) based on sum of ranks. The number and type of main traits were taken in three different combinations.
The index based on desired gains, equivalent to one genetic standard deviation, was less efficient. Acceptable gains were obtained for the remaining index criteria. The classic index of Hazel and Smith showed slight superiority in terms of total gain and distribution of gains among traits. In this case, the genetic coefficients of variation taken as economic weights was found to be an acceptable alternative as a set of initial values.

Keywords: Selection; Corn progenies.

REFERENCES

Anderson, J.C. and Crow, P.W. (1963). Phenotypes and grain yield associated with brachytic-2 gene in single-cross hybrids of dent com. Crop. Sci. 3: 111-113.

Crosbie, T.M., Mock, J.J. and Smith, D.S. (1980). Comparison of gains predicted by several selection methods for cold tolerance traits of two maize populations. Crop. Sci. 20: 649-655.

Elston, R.C. (1963). A weight-free index for the purpose of ranking or selection with respect to several traits at a time. Biometrics 19: 85-97.

Falconer, D.S. (1981). Introdução à genética quantitativa. (Tradução de Silva, M.A. e Silva, J.C.). Universidade Federal de Viçosa, Viçosa, pp. 279.

Gutierrez, A.D. (1974). Estimação de Indice de seleção para um composto de milho. Masters Thesis. ESAL/USP, Piracicaba.

Hazel, H.N. (1943). The genetic basis for constructing selection indexes. Genetics 28: 476-490.

Kauffmann, K.D. and Dudley, J.W. (1979). Selection indices com grain yield, percent protein, and kernel weight. Crop. Sci. 19: 583-588.

Kempthorne, O. and Nordskog, A.W. (1959). Restricted selection index. Biometrics 15: 10-19.

Lin, C.Y. (1978). Index selection for genetic improvement of quantitative characters. Theor. Appl. Genet. 52: 49-56.

Mulamba, N.N. and Mock, J.J. (1978). Improvement of yield potential of the Eto Blanco maize (Zea mays L.) population by breeding for plant traits. Egypt. J. Gen. Cytol. 7: 40-51.

Pesek, J. and Baker, R.J. (1969). Desired improvement in relation to selected indices. Can. J. Plant Sci., 49: 803-804.

Regazzi, A.J. (1978). Variâncias, covariâncias genéticas e indices de seleção num composto de milho (Zea mays L.). Masters Thesis, Universidade Federal de Viçosa, Viçosa.

Reis, F.P. (1981). Herdabilidade, correlações e indices de seleçao em milho (Zea mays L.). Masters Thesis, Universidade Federal de Viçosa, Viçosa.

Robison, H.F., Comstock, R.E. and Harvey, P.H. (1951). Phenotypic correlations in com and their implications in selection. Agron. J. 43: 282-287.

Smith, H.F. (1936). A discriminant function for plant selection. Ann. Eu gen. 7: 240-250.

ST Martin, S.K., Loesch, P.J. Jr. and Hanauer, A.R. (1986). Heritabilities, correlations and index selection in BSBBS2 maize synthetic. Maydica 31: 325-333.

Subandi, W., Compton, A. and Empig, L.T. (1973). Comparison of the efficiencies of selection indices for three traits in two variety crosses of corn. Crop. Sci. 13: 184-186.

Suwantaradon, K., Eberhart, S.A., Mock, I.J., Owens, J.C. and Guthrue, W.D. (1975). Index selection for several agronomic traits in the BSSS2 maize population. Crop. Sci. 15: 827-833.

Tai, G.C.G. (1977). Index selection with desired gains. Crop. Sci. 17: 182-183.

Vieira, I.V. (1988). Herdabilidade, correlações e índice de seleção em populações de cenoura (Daucus carota L.). Doctoral Thesis, Universidade Federal de Viçosa, Viçosa.

Williams, J.S. (1962). The evaluation of a selection index. Biometrics 18: 375-393.

* Part of a thesis presented by C.D.C. to ESALQ/USP in partial fulfillment of the requirements for the Doctoral degree