USP tropical maize hybrid panel

906 maize single-crosses obtained from a full dial- lel, according to Griffing’s method 4, divided into two heterotic groups, flint and dent, with 34 and 15 lines, respec- tively. Moreover, each heterotic group has a representative line, frequently used as the tester in our breeding program.

The experimental scheme used to evaluate the hybrids was an augmented block design (unreplicated trial) consisted of small blocks, each with 16 unique hybrids and two checks. Trials were carried out in Anhembi (22°50′51′′S, 48°01′06′′W, 466 m) and Piracicaba, at São Paulo State, Brazil (22°42′23′′S, 47°38′14′′W, 535 m), during the second growing season of 2016 and 2017, cultivated between January to June. In both sites and years, the hybrids were evaluated under two nitrogen (N) levels, low (LN) with 30 kg N ha−1, and normal (NN) with 100 kg N ha−1.

The genotyping of the 49 tropical inbred lines was per- formed by Affymetrix® platform, containing about 614,000 SNPs (Unterseer et al. 2014). Then, markers with low call rate (< 95%), minor allele frequency (MAF < 0.05) and heterozygous loci on at least one individual were removed. The missing markers were imputed using the snpReady R package. Finally, the resulting 146,365 SNPs high-quality polymorphic SNPs were used to build the artificial hybrids genomic matrix, deduced by combining the genotypes from its two parents.