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Champaign, IL, United States

Mikel M.A.,Urbana University | Mikel M.A.,Maize Lineage LLC
Crop Science | Year: 2011

Germplasm of contemporary U.S. dent corn (Zea mays L.) is predominately from proprietary programs. Although publicly developed inbred lines contributed to the genetic foundation of these programs, their role is not known. The objective of this work is to identify and characterize major progenitors of contemporary proprietary germplasm through pedigree analysis of a set of 305 corn inbreds registered during the years 2004 through 2008 by U.S. Plant Variety Protection (PVP) and/or utility patent. Major progenitors found were the inbred lines Dekalb DK3IIH6 (12.2% genetic contribution), B73 (11.7%), and Pioneer Hi-Bred International (PHI) PH207 (9.5%). Using commercial hybrids as breeding germplasm was common during the 1980s and facilitated the introgression of PHI Iodent germplasm into competitor breeding programs. Of these, the PHI commercial hybrid 3737 has the greatest impact to contemporary germplasm by contributing 15.6% of the genes. Pedigree analysis of 1132 U.S. PVP and/or utility patent registered corn inbreds from 1984 through 2008 indicates that the genetic contribution of the public line Mo17 has decreased (from 8.6 to 1.7%) and the contribution of the public line Oh43 increased (from 1.5 to 3.9%), whereas the contribution of B73 remained constant. The contribution of Iodent germplasm increased concomitantly with use across commercial breeding programs. © Crop Science Society of America. Source

Mikel M.A.,Urbana University | Mikel M.A.,Maize Lineage LLC
Genetic Resources and Crop Evolution | Year: 2013

A major objective of this work is to elucidate the ancestry and genetic background of contemporary U.S. garden pea (Pisum sativum L. convar. medullare Alef.) cultivars used as cultivated vegetables. This is facilitated through pedigree analysis of 147 cultivars registered during the era from 1990 through 2010 by collecting data from U.S. Plant Variety Protection, U.S. utility patent, and journal publication. Proprietary breeding programs developed 141 cultivars and public programs six, with over half (82 of 147 cultivars) originating from the two (Seminis Vegetable Seeds, Inc. and Syngenta Seeds, Inc.) largest proprietary breeding programs. During this era, the semi-leafless (afila) trait was bred into cultivars to decrease lodging, and 43 % of the cultivars were afila. Registered cultivars were 86 % of determinate growth habit. Bi-parental breeding crosses were used in the development of 78 % of these cultivars. The lineages of the cultivars 'Bolero', 'Spring', 'Genie', and 'Rally' made large contributions to the genetic composition of this germplasm, 'Bolero' contributed 6.5 % (29 progeny), 'Spring' 6.4 % (29), 'Genie' 4.0 % (18), and 'Rally' 3.6 % (23) of the genes. The garden pea ancestor cultivar 'Perfection' fostered the most descendants (75) among the 147 cultivars of this era. © 2013 Springer Science+Business Media Dordrecht. Source

Mikel M.A.,Urbana University | Mikel M.A.,Maize Lineage LLC
Genetic Resources and Crop Evolution | Year: 2013

Pedigree history of 146 lettuce (Lactuca sativa L.) cultivars registered in the U. S. by Plant Variety Protection and/or utility patent of the era from 2000 through 2010 facilitates determination of coefficient of parentage among these cultivars, identification of ancestral parental lines, and their genetic contribution. Principal ancestors of leaf lettuce developed in this era are the cultivars 'Malibu', 'Waldmann's Green', and 'Salad Bowl' contributing 6.4, 6.1, and 3.5% of the genes, respectively. The cultivars 'Parris Island Cos' and 'Tall Guzmaine' are major ancestors of romaine lettuce, contributing 25.9 and 23.4% of the genes, respectively. Three crisphead lettuce ancestors identified are the cultivars 'Vanguard', 'Salinas', and 'Calmar', the former two descend from interspecific crosses of L. sativa with Lactuca virosa L. and Lactuca serriola L. Among these three, 'Vanguard' is the major ancestor contributing 23.8% of the genes to crisphead lettuce. The crisphead cultivar 'Salinas' was frequently crossed with romaine lettuce types and the romaine parental cultivar 'Parris Island Cos' was crossed with leaf types contributing to romaine and leaf lettuce genetic diversity, respectively. Genetic similarity was less within leaf cultivars (coefficient of parentage = 0.02) than found within romaine (0.15) and crisphead (0.13) cultivars registered in the U. S. during this era. © 2012 Springer Science+Business Media Dordrecht. Source

Mikel M.A.,Urbana University | Mikel M.A.,Maize Lineage LLC | Diers B.W.,Urbana University | Nelson R.L.,Urbana University | Smith H.H.,Brandy Wine Seed Farms LLC
Crop Science | Year: 2010

From 1970 to 2008 there were 2242 soybean [Glycine max (L.) Merr.] cultivars registered in North America through U.S. Plant Variety Protection (PVP), U.S. utility patent, and journal registration. Of these, 80% were developed through proprietary and 20% through public programs. Our objective was to characterize the development and genetic diversity of North American soybean cultivars. The most frequently used germplasm for cultivar development were the cultivars Williams (parent used in last cross before inbreeding in 70 cultivars), A3127 (63), Essex (45), Amsoy (38), Corsoy (33), Wayne (30), Forrest (27), Hutcheson (25), MO13404 (23), and Bedford (23). Genetic diversity (1 - coefficient of parentage), estimated from pedigree lineage, was 0.89 overall. Genetic diversity was the same within public (0.89) and proprietary (0.89) culti-vars. The cultivar A3127 is a major progenitor of recently developed proprietary cultivars registered from 1999 to 2008. Of these 494 cultivars, 23% have a genetic contribution of at least 25% from A3127. New cultivars were predominantly developed from the following crosses: two-parent (70% of cultivars developed), complex (12%), three-parent (5%), one backcross (5%), multiple (two, three, or four) backcrosses (3%), and five or greater backcrosses (2%). In comparisons where both parent and progeny were evaluated together, seed yield increased 3.2% per breeding cycle. In these comparisons, seed yield had a correlation of 0.29 with parental diversity. © Crop Science Society of America. Source

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