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Indirect response in yield and harvest index to recurrent selection for stalk quality and corn-borer resistance in maize*
P.N. Rehn; W.A. Russell
ABSTRACT
Two populations of maize (Zea mays L.) were improved by recurrent selection for stalk quality and/or resistance to the European corn borer, Ostrinia nubilalis (Hübner). The open-pollinated variety, `Lancaster', was selected for seven cycles for resistance to Diplodia maydis stalk rot and increased mechanical stalk strength [BSL(S)]. Three cycles of selection were used to improve the `BS1' synthetic for Diplodia stalk-rot resistance (BS1SR), increased mechanical strength (BS1MS), resistance to leaf feeding by the European corn borer (BS1LF), or increased concentration of DIMBOA (BS1DM). Populations and population testcrosses were evaluated for the correlated responses in total plant yield, stover weight, grain yield, and harvest index. The BSL(S) cycle populations showed increases in total yield and stover weight and decreases in grain harvest index and grain yield. BS1SR and BS1MS populations revealed that selection resulted in grain yield and harvest index reductions. Selection for corn-borer resistance (BS1LF and BS1DM) caused reductions in total yield, stover weight, and grain yield with no changes in harvest index. The results indicate that selection for stalk quality resulted in changes in the translocation balance, with more of the photosynthates being used in the stover and, consequently, less being available for the kernels. Selection for cornborer resistance resulted in a general loss of vigor and earlier maturity, but no changes were observed in the partitioning of the photosynthates.
Keywords: selection; stalk quality; corn-borer.
REFERENCES
Craig, J. and Hooker, A.L. (1961). Relation of sugar trends and pith density to Diploida stalk rot in dent corn. Phytopathology 51: 376-382.
Devey, M.E. and Russell, W.A. (1983). Evaluation of recurrent selection for stalk quality in a maize cultivar and effect on other agronomic traits. Iowa State J. Rea 58: 207-219.
Jinahyon, S. and Russell, W.A. (1969a). Evaluation of recurrent selection for stalk-rot resistance in an open-pollinated variety of maize. Iowa State J. Sci. 43: 229-237. -
Jinahyon, S. and Russell, W.A. (1969b). Effects of recurrent selection for stalk-rot resistance on other agronomic characters in an open-pollinated variety of maize. Iowa State J. Sci. 43: 239-251.
Martin, M.J. and Russell, W.A. (1984a). Response of a maize synthetic to recurrent selection for stalk quality. Crop Sci. 24: 331-337.
Martin, M.J. and Russell, W.A. (1984b). Correlated responses of yield and other agronomic traits to recurrent selection for stalk quality in a maize synthetic. Crop Sci 24: 746-750.
Rehn, P.N. (1985). Correlated responses for grain yield and other agronomic traits with recurrent selection for improved stalk quality or for resistance to the European corn borer in two maize populations. Masters Thesis. Iowa State University Library, Ames, Iowa.
Tseng, C.T., Guthrie, W.D., Russell, W.A., Robbins, J.C., Coats, J.R. and Tollefson, J.J. (1984). Evaluation of two procedures to select for resistance to the European corn borer in a synthetic cultivar of maize. Crop Sci 24: 1129-1133.
* Joint contribution: USDA-ARS and Journal Paper No. J-12032 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011. Project No. 2194. Part of a thesis submitted by P.N.R. in partial fulfillment of the M.S. degree. Send correspondence to W.A.R., Department of Agronomy, Iowa State University, Ames, Iowa 50011, USA.