Optimum exploitation of heterosis utilizing the concept of heterotic groups and patterns in hybrid breeding
Final Report Abstract
Abstract Maize (Zea mays L.) breeders are concerned about the narrowing of the genetic base of elite germplasm. To reverse this trend, elite germplasm from other geographic regions can be introgressed, but due to lack of adaptation it is difficult to assess their breeding potential in the targeted environment. The objectives of this study were to investigate the relationship between European and US maize germplasm, examine the suitability of different mega-environments and measures of performance to assess the breeding potential of exotics, and study the relationship of genetic distance with mid-parent heterosis (MPH). Eight European inbreds from the Dent and Flint heterotic groups, 11 US inbreds belonging to Stiff Stalk (SS), non-Stiff Stalk (NSS), and CIMMYT Pool 41, and their 88 factorial crosses in F1 and F2 generations were evaluated for grain yield and dry matter concentration. The experiments were conducted in three mega-environments: Central Europe (target mega-environment), US Cornbelt (mega-environment where donor lines were developed), and Southeast Europe (an intermediate mega-environment). The inbreds were also fingerprinted with 266 SSR markers. Suitable criteria to identify promising exotic germplasm were F1 hybrid performance in the targeted mega-environment and F1 and parental performance in the intermediate mega-environment. Marker-based genetic distances reflected relatedness among the inbreds, but showed no association with MPH. Based on genetic distance, MPH, and F1 performance, we suggest to introgress SS germplasm into European Dents and NSS into European Flints, in order to exploit the specific adaptation of European flint germplasm and the excellent combining ability of US germplasm in European maize breeding programs.
Publications
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(2007) Impact of interpopulation divergence on additive and dominance variance in hybrid populations. Genetics 176:1931-1934
Reif JC, Gumpert FM, Fischer S, Melchinger AE
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(2008) Trends in genetic variance components during 30 years of hybrid maize breeding at the University of Hohenheim. Plant Breeding 127:446-451
Fischer S, Möhring J, Schön CC, Piepho H-P, Klein D, Schipprack W, Utz HF, Melchinger AE, Reif JC
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(2009) Impact of genetic divergence on the ratio of variance due to specific versus general combining ability in winter triticale. Crop Sci 49:2119–2122
Fischer S, Möhring J, Maurer HP, Piepho H-P, Thiemt E-M, Schön CC, Melchinger AE, Reif JC
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(2009) Unraveling epistasis with triple testcross progenies of near-isogenic lines. Genetics 181:247-257
Reif JC, Kusterer B, Piepho H-P, Meyer RC, Altmann T, Schön CC, Melchinger AE
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(2010) Broadening the genetic base of European maize heterotic pools with US Cornbelt germplasm using field and molecular marker data. Theor Appl Genet 120:301- 310
Reif JC, Fischer S, Schrag TA, Lamkey KR, Klein D, Dhillon BS, Utz HF, Melchinger AE
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(2010) Development of heterotic groups in triticale. Crop Sci 50:584-590
Fischer S, Maurer HP, Würschum T, Möhring J, Piepho H-P, Schön CC, Thiemt E-M, Dhillon BS, Melchinger AE, Reif JC
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(2010) Molecular marker assisted broadening of the Central European heterotic groups in rye with Eastern European germplasm. Theor Appl Genet 120:291-299
Fischer S, Melchinger AE, Korzun V, Wilde P, Schmiedchen B, Möhring J, Piepho H-P, Dhillon BS, Würschum T, Reif JC
