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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #284714
Title: Genome-wide selection versus marker-assisted recurrent selection to improve grain yield and stover-quality traits for cellulosic ethanol in maize

Author
item MASSMAN, JON - University Of Minnesota
item Jung, Hans Joachim
item BERNARDO, REX - University Of Minnesota

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2012
Publication Date: N/A
Citation: N/A

Interpretive Summary: Creating new corn hybrids requires development of parental lines that have been selected for improved performance characteristics. This selection is done by measuring the actual performance of many potential parental corn plants and then mating the best individual plants to create a new generation of corn lines for another round of selection. Typically, eight or more rounds of testing and mating are required to develop an improved parental corn line for use in new hybrids. To speed this development process, it has been proposed that genetic molecular markers associated with the performance trait of interest can be identified in the potential parents and then selection of plants for mating and further evaluation can be done using the molecular marker profiles of subsequent generations without the need for expensive and time-consuming performance evaluation. This study compared the effectiveness of only using molecular markers that had a statistically significant association with performance for the selection of parent plants vs. using all molecular markers available, without regard to significance of the association. After two cycles of selection using markers, greater improvement in corn stover characteristics of value to cellulosic ethanol production was achieved when all available molecular markers were used for selection compared with using only those markers that had a statistically significant association with cellulosic ethanol traits. This is the first experimental confirmation of the value of using all molecular markers for corn parent development. These results will provide corn breeders with confidence that this form of marker-assisted selection is a useful tool for speeding corn hybrid development.

Technical Abstract: Genome-wide selection (GWS) is marker-assisted selection without identifying markers with significant effects. Our previous work with the intermated B73 x Mo17 maize (Zea mays L.) population revealed significant variation for grain yield and stover-quality traits important for cellulosic ethanol production. Our objectives were to determine: (i) if realized gains from selection are larger with GWS than with marker-assisted recurrent selection (MARS), which involved selection for markers with significant effects; and (ii) how multiple traits respond to multiple cycles of GWS and MARS. In 2007, test crosses of 223 recombinant inbreds developed from B73 x Mo17 (Cycle 0) were evaluated at four Minnesota locations and genotyped with 287 single nucleotide polymorphism markers. Individuals with the best performance for a Stover Index and a Yield + Stover Index were intermated to form Cycle 1. Both GWS and MARS were then conducted until Cycle 3. Multilocation trials in 2010 indicated that gains for the Stover Index and Yield + Stover Index were 14 to 50% larger (significant at P = 0.05) with GWS than with MARS. Gains in individual traits were mostly nonsignificant. Inbreeding coefficients ranged from 0.28 to 0.38 by Cycle 3 of GWS and MARS. For stover quality traits, correlations between wet chemistry and near-infrared reflectance spectroscopy predictions decreased after selection. We believe this is the first published report of a GWS experiment in crops, and our results indicate that using all available markers for predicting genotypic value leads to greater gain than using a subset of markers with significant effects.