Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: MAPPING OF QUANTITATIVE TRAIT LOCI IN TEST-CROSSES OF MAIZE:
COMPARISON AMONG ENVIRONMENTS, TESTERS, AND POPULATIONS
MAPPING OF QUANTITATIVE TRAIT LOCI IN TEST-CROSSES OF MAIZE:
COMPARISON AMONG ENVIRONMENTS, TESTERS, AND POPULATIONS.
A.E. Melchinger, C.C. Schon, S. Fahr, Universitat Hohenheim,
70593 Stuttgart, Germany; J. Boppenmaier, E. Brunklaus-Jung, R.G.
Herrmann, Ludwigs-Maximilians-Universitat Munchen, 80638 Munchen,
Germany; A. Daily, P. Westhoff, Universitat Dusseldorf, 4000
Dusseldorf, Germany.
Use of molecular markers to identify quantitative trait loci
(QTL) of agronomically important traits will reveal their genetic
basis and help to design more efficient breeding strategies.
Results are presented from experiments in maize, in which we
mapped and characterized QTL affecting testcross performance with
the aid of RFLP markers and compared the consistency of these QTL
across environments, testers, and populations. In experiment 1,
380 F, lines from population A x B were evaluated for testcross
performance in 4 environments with two unrelated testers (T1,
T2). Experiment 2 comprised testcrosses of T2 with 120 F3, and
F4 lines from populations A x B and C x D, respectively, grown in
different environments. In experiment 1, a minimum of 4 QTL were
detected for each trait (kernel weight, protein content, plant
height) explaining at least 32% of the total phenotypic variance.
Results from QTL mapping agreed well across environments despite
significant genotype x environment interactions. Highly
consistent results across testers were found for two traits.
Comparisons among populations showed discrepancies in the
position and effects of QTL. Implications of our findings with
regard to applications in practical breeding programs are
discussed.
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