Demand-Driven Technologies for Sustainable Maize ... - IITA

52employed to exploit non-additive gene action to improve droughttolerance. The signifi cant correlations of hybrid means and mid-parentvalues also indicated that drought tolerant inbred lines generallyproduced drought tolerant hybrids.AcknowledgementThis research was conducted at the International Institute of TropicalAgriculture (IITA), and was funded by the Maize Improvement Unit.ReferencesBetran, F.J., D. Beck, M. Banziger and G.O. Edmeades, 2003. Geneticanalysis of inbred and hybrid grain yield under stress and nonstressenvironments in tropical maize. Crop Science 43:807–817.Bolanos, J. and G.O. Edmeades, 1993. Eight cycles of drought tolerance inlowland tropical maize. I. Response in grain yield, biomass, and radiationutilization. Field Crops Research 31:233–252.Cochran, W.G. and G.M. Cox, 1960. Experimental Designs. John Wiley andSons, New York, USA. 611 pp.Comstock, R.E. and H.F. Robinson, 1948. The components of geneticvariance in population of biparental progenies and their use in estimatingthe average degree of dominance. Biometrics 4:254–266.Duvick, D.N., 1992. Genetic contributions to advances in yield of U.S. maize.Maydica 37:69–79.Hallauer, A.R. and J.B. Miranda. 1988. Quantitative genetics in maize breeding.2 nd Edition. Iowa State University Press; Ames, Iowa, USA. 468 pp.Kirkham, M.B., K. Suksayretrup, C.E. Wassom and E.T. Kanemasu, 1984.Canopy temperature of drought-resistant and drought-sensitivegenotypes of maize. Maydica 29: 287–303.Menkir, A. and A.O. Akintunde, 2001. Evaluation of the performance of maizehybrids, improved open-pollinated and farmers’ local varieties under wellwatered and drought stress conditions. Maydica 46:227–238.NeSmith, D.S. and J.T. Ritchie, 1992. Effects of soil water defi cit during tasselemergence on development and yield components of maize (Zea maysL.). Field Crops Research 28:251–256.SAS Institute, 1999. The SAS system for Windows. Release 8.2. SAS Inst.,Cary, NC, USA.Singh, R.K. and B.D. Chaudhary, 1985. Biometrical methods in quantitativegenetic analysis. Kalyani Publisher, New Delhi, India. 318 pp.Tollenaar, M. and E.A. Lee, 2002. Yield potential, yield stability and stresstolerance in maize. Field Crops Research 75:161–169.Verma, O. P. and H. K. Srivastava, 2004. Genetic components and combingability analysis in relation to heterosis for yield and associated traits usingthree diverse rice-growing ecosystems. Field Crops Research 88:91–102.