Comparing Conventional Early Generation Selection with Molecular Marker Assisted Selection in Maize
1994
Stromberg, L. D. | Dudley, J. W. | Rufener, G. K.
To be useful to plant breeders, gains made from molecular marker-assisted selection (MAS) must be more cost-effective than gains made through traditional breeding. The objective of this research was to evaluate the effectiveness of MAS in an applied maize (Zea mays L.) breeding program. Maize population BS11 (FR) C₇ was chosen to improve hybrid FRMo17 × FRB73. FRMo17 and BS11 were crossed, then random-mated to create F₂ plants (families). F₂ plants were testcrossed to FRB73 and genotyped with 34 molecular markers. F₂ families were selfed to create F₂:S₄ families. Based on F₂ testcross yield, the top 20 families were selected. A second set of 20 families was selected based on a marker-derived selection index. Marker genotypes were obtained for 20 plants within each of the marker selected families. Index selections were made for favorable and unfavorable genotypes within the 20 families. F₂:S₄ testcrosses to FRB73 were grown to compare the different selection methods. Selection among F₂:S₄ families using either method resulted in similar testcross performance. However, neither method selected families that performed significantly better than FRMo17 × FRB73 or the Sₒ unselected population testcross. Within-family index selection was not effective. The selection index, developed with F₂ testcross data, was not correlated with F₂:S₄ testcross performance. Marker-yield associations were determined using F₂:S₄ genotypic and testcross performance data. Ten (31%) markers were significantly associated with yield. One marker-allele combination was favorable (and significant) in both F₂ and F₂:S₄ testcross performance. Contribution from the Dep. of Agronomy, Univ. of Illinois. Supported in part by the Illinois Agric. Exp. Stn. and by a grant from ICI Research, Slater, IA.
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