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Divergent mass selection for ear length in maize^*

Artemio M. Salazar^I; Arnel R. Hallauer^II

^IInstitute of Plant Breeding, College, Laguna, The Philippines
^IIU.S. Department of Agriculture, Agronomy Department, Iowa State University, Ames, Iowa 50011, USA. Send correspondence to A.R.H.

ABSTRACT

Divergent mass selection for ear length was initiated in 1963 to determine the effects of selection on grain yield in Iowa Long Ear (BSLE) maize (Zea mays L.) synthetic. Evaluation of original and advanced cycles of BSLE subpopulations showed significant but asymmetrical responses for ear length and most of the other traits. Greater response was exhibited with selection for shorter ears. The asymmetrical response for ear length probably was due to genetic asymmetry and greater environmental sensitivity of the long-ear subpopulation compared with the short-ear subpopulation. Indirect selection, based on ear length, was not effective for increasing grain yield.
Genetic variation after 15 cycles of selection was found to be similar to that of the original BSLE population. Further progress was predicted and would likely be asymmetrical in future cycles of divergent mass selection for ear length. The trends of divergent response for some traits correlated with ear length were predicted not to continue or even change in direction, suggesting that the response limits for such traits had been reached.

Keywords: mass selection; ear length; maize.

REFERENCES

Ariyanayagam, R.P., Moore, C.L. and Carangal, V.R. (1974). Selection for leaf angle in maize and its effect on grain yield and other characters. Crop Sci. 14: 551-556.

Ceccarelli, S. and Grando, S. (1981). Divergent selection for culm length in barley. III. Responses to six cycles of within-families selection. Z. Pflanzenzuecht. 86:56-68.

Cortez-Mendoza, H. and Hallauer, A.R. (1979). Divergent mass selection for ear length in maize. Crop Sci. 19: 175-178.

Crosbie, T.M. and Pearce, R.B. (1982). Effects of recurrent phenotypic selection for high and low photosynthesis on agronomic traits in two maize populations. Crop. Sci. 21: 736-740.

Dudley, J.W. (1977). Seventy-six generations of selection for oil protein percentage in maize. In: Proc. Int. Conf. Quant. Genet. (Pollak, E., Kempthorne, O. and Bailey, T.B., Jr., eds.) Iowa State Univ. Press, Ames, pp. 459-473.

Eberhart, S.A. (1964). Least squares method for comparing progress among recurrent selection methods. Crop Sci. 4: 230-231.

Falconer, D.S. (1981). Introduction to Quantitative Genetics. Longman Inc., New York.

Gardner, C.O. (1961). An evaluation of effects of mass selection and seed irradiation with thermal neutrons on yield of corn. Crop Sci. 1: 241-245.

Goodman, M.M. (1965). Estimates of genetic variance in adapted and exotic populations of maize. Crop Sci. 5: 87-90.

Hallauer, A.R. and Miranda, J.B., Fo. (1981). Quantitative Genetics in Maize Breeding. Iowa State Univ. Press, Ames.

Hallauer, A.R. and Sears, J.H. (1969). Mass selection for yield in two varieties of maize. Crop Sci. 9:47-50.

Hallauer, A.R. and Wright, J.A. (1967). Genetic variance in the open pollinated variety of maize Iowa Ideal. Zuchter 37: 178-185.

Hammond, J.J. and Gardner, C.O. (1974). Modifications of the variety cross diallel model for evaluating cycles of selection. Crop Sci. 14: 6-8.

Johnson, E.C. (1963). Mass selection for yield in a tropical corn variety. Am. Soc. Agron. Abstr., p. 82.

Josephson, L.M., Kincer, H.C. and Harville, B.G. (1976). Selection studies for low ear placement in corn. Proc. Annu. Corn Sorghum Res. Conf. 31: 85-97.

Kincer, H.C. and Josephson, L.M. (1976). Mass selection for prolificacy in corn. Agron. Abstr., p. 55.

Lantin, M.M. (1980). Observed response and genetic variability in two maize populations after four cycles of reciprocal full-sib selection. Ph. D. Dissertation. Iowa State Univ., Ames, Iowa.

Lonnquist, J.H. (1967). Mass selection for prolificacy in maize. Zuchter 37: 185-188.

Mareck, J.H. and Gardner, C.O. (1979). Response to mass selection in maize and stability of resulting populations. Crop Sci. 19: 779-783.

Mulamba, N.N., Hallauer, A.R. and Smith, O.S. (1983). Recurrent selection for grain yield in a maize population. Crop Sci. 23: 536-540.

Robinson, H.F., Comstock, R.E. and Harvey, P.H. (1951). Genotypic and phenotypic correlations in corn and their implications in selection. Agron. J. 43: 282-287.

Russell, W.A., Penny, L.H., Hallauer, A.R., Eberhart, S.A., Scott, G.E., Guthrie, W.D. and Dicke, F.F. (1971). Registration of maize germplasm synthetics. Crop Sci. 11: 140-141.

Searle, S.R. (1965). The value of indirect selection. I. Mass selection. Biometrics 21: 682-707. Smith, O.S. (1979a). A model for evaluating progress from recurrent selection. Crop Sci. 19: 223-226.

Smith, O.S. (1979b). Application of a modified diallel analysis to evaluate recurrent selection for grain yield in maize. Crop Sci. 19: 819-822.

Torregroza, M. (1973). Response of a highland maize synthetic to eleven cycles of divergent mass selection for ears per plant. Agron. Abstr., p. 20.

Torregroza, M. and Harpstead, D.D. (1967). Effects of mass selection for ears per plant in maize. Agron. Abstr., p. 20.

Troyer, A.F. and Brown, W.L. (1976). Selection for early flowering in corn. Crop Sci. 16: 767-772.

Williams, J.C., Penny, L.H. and Sprague, G.F. (1965). Full-sib and half-sib estimates of genetic variance in an open-pollinated variety of corn, Zea mays L. Crop Sci. 5: 125-129.

* Joint contribution: USDA, ARS, and Journal Paper No. J-12203 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011. Project No. 2194. Part of a dissertation submitted by A.M.S. in partial fulfillment of the requirements for Ph. D.