Ld. Stromberg et al., COMPARING CONVENTIONAL EARLY GENERATION SELECTION WITH MOLECULAR MARKER ASSISTED SELECTION IN MAIZE, Crop science, 34(5), 1994, pp. 1221-1225
To be useful to plant breeders, gains made from molecular marker-assis
ted selection (MAS) must be more cost-effective than gains made throug
h traditional breeding. The objective of this research was to evaluate
the effectiveness of MAS in an applied maize (Zea mays L.) breeding p
rogram. Maize population BS11 (FR) C-7 was chosen to improve hybrid FR
Mo17 x FRB73. FRMo17 and BS11 were crossed, then random-mated to creat
e Fz plants (families). F-2 plants were testcrossed to FRB73 and genot
yped with 34 molecular markers. F-2 families were selfed to create F-2
:S-4 families. Based on F-2 testcross yield, the top 20 families were
selected. A second set of 20 families was selected based on a marker-d
erived selection index. Marker genotypes were obtained for 20 plants w
ithin each of the marker selected families. Index selections were made
for favorable and unfavorable genotypes within the 20 families. F-2:S
-4 testcrosses to FRB73 were grown to compare the different selection
methods. Selection among F-2:S-4 families using either method resulted
in similar testcross performance. However, neither method selected fa
milies that performed significantly better than FRMo17 x FRB73 or the
S-0 unselected population testcross. Within-family index selection was
not effective. The selection index, developed with F-2 testcross data
, was not correlated with F-2: S-4 testcross performance. Marker-yield
associations were determined using F-2:S-4 genotypic and testcross pe
rformance data. Ten (31%) markers were significantly associated with y
ield. One marker-allele combination was favorable (and significant) in
both F-2 and F-2:S-4 testcross performance.