从实生苗精选出来的株系种在T1小区阶段.对每个株系要准备有6米长和1.2米间隔的单行小区。每第20个小区是种对照品种,通常大部分是种在由地区选种站提供的每个地区。往往有二个不同成熟度的对照品种做为重复对照。如前所述,每年被精选出做为T1阶段之用的平均有12860个品系(2.47％)(表3). The strains selected from the seedlings are planted in the T1 cell stage, and for each line, a single row of cells of 6 m length and 1.2 m spacing is prepared. Each 20th district is a control breed and is usually planted mostly in each area provided by the regional selection station. There are often two different maturity control varieties as a duplicate control. As mentioned earlier, an average of 12860 lines (2.47%) were selected each year for the T1 period (Table 3).