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Comparison of Different Methods of Identifying Inbreds Useful for Improving Elite Maize Hybrids
Author(s) -
Zai Urs,
Dudley J. W.
Publication year - 1989
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1989.0011183x002900030005x
Subject(s) - diallel cross , hybrid , inbred strain , biology , zea mays , grain yield , agronomy , allele , microbiology and biotechnology , genetics , gene
The identification of inbred lines (I w ) as sources of favorable alleles not already present in an elite hybrid (I 1 × I 2 ) is an essential part of a pedigree corn breeding program. The objective of this study was to compare different methods of estimating the value of an inbred as a parent for improving performance of an elite hybrid. A nonreciprocal diallel of four maize ( Zea mays L.) inbreds derived from Stiff Stalk Synthetic (B73, B84, N7A, and H100), five derived from Lancaster (Pa91, Mo 17, H95, H102, and Va26), and five unrelated to Stiff Stalk Synthetic or Lancaster (B77, B57, B75, B79, and N152) was evaluated for grain yield, grain dry matter percentage, earliness of flowering, and plant and ear height at two locations in 1984 and 1985. A minimally biased estimate of the number of favorable alleles present in an inbred but not present in an elite hybrid (μG*) was compared with an earlier biased estimate μG), minimum upper bound estimates (UBND), inbred performance per se, general combining ability (GCA) estimates, and predicted three way performance (PTC). The μG* estimates were highly correlated with PTC and UBND estimates for most traits and with GCA for traits where additive genetic effects are of major importance. Correlations of μG* with the original μG and inbred performance per se were generally low. When the top two lines were selected within each of the 91 hybrids for the magnitude of μG* for grain yield, Pa91 was the line most often chosen followed by B73, B84, and Mol7. Estimates of relative genetic distance of I w to I 1 or I 2 agreed well with pedigree information.