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Evaluation of Maize Populations as Sources of Favorable Alleles for Improvement of Two Single-Cross Hybrids

Stojšin, Duška, Kannenberg, L. W.
Crop science 1995 v.35 no.5 pp. 1353-1359
Zea mays, hybrids, recurrent selection, alleles, genetic improvement, inbred lines, backcrossing, agronomic traits, recessive genes, plant breeding, breeding methods, selfing, population
Adapted and selected populations are expected to be good sources of favorable alleles for immediate improvement of an elite hybrid. We studied 17 maize (L.) populations from recurrent selection programs based on performance indices (involving grain yield, moisture, and lodging). These populations represented initial (CO) and advanced selection cycles (Cn) in five sources: CGSynA, CGSynB, CGG,C GN, and CGWT. he objectives of this study were to (i) identify populations that are the best sources of favorable alleles to be used for improving two single-cross hybrids (CG28 × CO265 and CGKX86 × CO265); (ii) estimate relationship values to determine which inbred parent should be improved; and (iii) determine if the inbred x population cross should be backcrossed to the inbred line prior to selfing. Generally, there were few significant differences among the 17 populations as potential sources for improving the two hybrids. This suggests that either the genetic method was not sensitive enough to detect differences among the populations or that in fact there were no real differences among them as sources of favorable alleles for the two single-cross hybrids. Generally, CGSynA(HS)C10 and CGW(RRS)C4 were the best sources of favorable alleles, whereas CGNC0 was the worst for improving performance indices and grain yield in the two hybrids. CGSynA,C GG, CGN, and CGW could be used for improving CG28 and CGKX86, whereas CGSynB would be a suitable source of favorable alleles for CO265. Generally, selfing would be the preferred method of developing improved inbred lines for most selected populations; backcrossing to the inbred line prior to selfing should be done if unadapted and/or unselected populations are used as sources of favorable alleles for improving hybrids.