Bernardo, "Prediction of maize single-cross
performance using RFLPs and information from related hybrids," Crop Science, vol.
1964: First company to successfully market single-cross
The increases over time are associated with better adaptedness, corn breeding, hybrid corn, mechanical harvest, better soil fertility (particularly more N), single-cross
hybrids that are easily identified by the farmer (better hybrid choice), field-shelling harvest (faster feed back for yield), improved cultural practices (particularly higher plant densities), and biotechnology.
Data across years showed that top population hybrids were not different statistically (P<0.05) from single-cross
hybrids for grain yield performance and for root and stalk lodging percentages.
[S.sub.2] testcrosses with Iowa Stiff-Stalk Synthetic (BSSS) related single-cross
tester B73/B94 were produced in 1993 and evaluated in trials at one site with conventional-tillage and one with minimum-tillage, near Wooster, and at an additional site near South Charleston, OH, in 1994.
hybrids involve crossing two highly related inbred lines together (A and [A.sup.*]) and using the related-line [F.sub.1] (A x [A.sup.*]; i.e., SL) as the female parent in the seed corn production fields.
DE3 and DE4 inbred lines ([S.sup.8]) were derived from a Germplasm Enhancement of Maize (GEM) breeding cross ([S.sup.0]) (Brazilian tropical maize single-cross
Dekalb hybrid DKXL212 crossed to elite non-Stiff Stalk temperate inbred N11a) using pedigree selection and early-generation yield testing initiated with [S.sup.2] lines testcrossed to LH198 and individual ear selection through the [S.sup.5] generation.
Early generation testing of NDSAB(MER-FS)C13 derived [S.sub.0] and [S.sub.1] lines have shown good combining ability with single-cross
unrelated tester LH176 x LH177 with higher grain yield performance and test weight, lower grain moisture at harvest, and similar lodging resistance than all checks (Pioneer 39D82, Wensman 5048Bt, and DKC35-51).
The 11 clones were matched pairwise based on leaf color, leaf texture, and synchronized flowering into a group of eight single-crosses
. For each single-cross
, the two clones were sprigged in alternating rows in isolation.
[S.sub.4] lines with combined resistance to the four diseases were crossed to two inbred testers, TZMI102 and TZMI407, that are parents of the best single-cross
hybrid marketed in Plateau State of Nigeria as '8535-23' to form testcrosses.
Previous studies suggest that such a relationship may occur in some cases, but it is far from reliable for predicting heterosis and single-cross
performance for use in a breeding program (Diers et al., 1996; Godshalk et al., 1990; Lee et al., 1989; Melchinger et al., 1990).