Full text in pdf format
Evaluation of four testers for evaluating maize (Zea mays L) lines in a hybrid develpment program
R. de Rissi; A.R. Hallauer
U.S. Department of Agriculture, Agronomy Department, Iowa State University, Ames, IA 50011, USA. Send correspondence to A.R.H.
ABSTRACT
Choice of tester is important in the evaluation of maize (Zea mays L.) lines for potential use in hybrids. The objective of this study was to determine the relative merits of four testers for evaluating inbred lines in a hybrid development program. One hundred S2 lines were derived from each of two brachytic (br2) populations under recurrent selection, and these were crossed to two genetically broad-based testers (parental and unrelated populations) and to two genetically narrow-based testers (an unrelated single cross and one inbred line). In all instances, variance component estimates of lines were greater than their respective line x tester interactions. Greater tester x line interaction did not occur with the use of narrow-based testers than with the use of broad-based testers. The parental-population testers provided more consistent discrimination among S2 lines. The results suggested that genetically narrow-based testers, such as inbred lines and single crosses, can be effectively used to identify lines having good general combining ability (GCA). There was evidence that unrelated testers and inbred-line testers with poor GCA and good performance per se were better testers for discriminating among S2lines. The highly significant phenotypic correlations between testers and the percentage of coincidence of selected lines with good GCA suggested that either type of tester can be used to classify 50% of lines with good combining ability.
Keywords: Zea mays; Hybrid; Development program.
REFERENCES
Comstock, R.E. and Moll, R.H. (1963). Genotype-environment interactions. In: Statistical Genetics and Plant Breeding (W.D. Hanson and H.F. Robinson, eds.). Natl. Acad. Counc.-Natl. Res. Counc., Washington, DC. pp. 164-196.
Hallauer, A.R. and Lopez-Perez, E. (1979). Comparisons among testers for evaluating lines of corn. Proc. Annu. Corn Sorghum Res. Conf. 34:57-75.
Hallauer, A.R. and Miranda, J.B., Fo. (1988). Quantitative Genetics in Maize Breeding. Iowa State Univ. Press, Ames, IA. 468 p.
Jenkins, M.T. and Brunson, A.M. (1932). Methods of testing lines of maize in crossbred combinations. J. Am. Soc. Agron. 24: 523-530.
Matzinger, D.F. (1953). Comparison of three types of testers for the evaluation of inbred lines of corn. Agron. J. 45: 493-495.
Rawlings, J.O. and Thompson, D.L. (1962). Performance level as criterion for the choice of maize testers. Crop Sci. 2: 217-220.