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.本数据集包含906个玉米单交种，源自完整双列杂交试验，采用格里芬（Griffing）方法4进行设计，按杂种优势群（heterotic groups）划分为硬粒型（flint）和马齿型（dent）两类，分别包含34和15个自交系。此外，每个杂种优势群均设有1个代表性自交系，本育种项目中常将其作为测验种（tester）使用。 用于评估该杂交种的试验方案采用增广区组设计（augmented block design，即非重复试验），每个小区块包含16个独特杂交种与2个对照品种（check）。试验分别于巴西圣保罗州的Anhembi（南纬22°50′51′′，西经48°01′06′′，海拔466米）与Piracicaba（南纬22°42′23′′，西经47°38′14′′，海拔535米）开展，试验时段为2016年与2017年的第二季生长季（1月至6月种植）。所有试验点与试验年份均设置两个氮肥（N）水平：低氮（LN）处理施氮30 kg·公顷⁻¹，正常氮（NN）处理施氮100 kg·公顷⁻¹。 本研究对49份热带自交系进行基因分型，采用Affymetrix®平台，该平台包含约614000个单核苷酸多态性（SNPs）标记（Unterseer等，2014）。随后，剔除检出率（call rate）低于95%、次要等位基因频率（minor allele frequency, MAF）低于0.05以及至少在1个个体中存在杂合位点（heterozygous loci）的标记。利用snpReady R包对缺失的标记数据进行填充（imputed）。最终，保留的146365个高质量多态性SNPs被用于构建人工杂交种的基因组矩阵（genomic matrix），该矩阵通过合并杂交种双亲的基因型推导得到。