Department of Agriculture, Universidade Federal de Goiás, C.P. 131, 74001, Goiánia GO, Brazil.
Theor Appl Genet. 1992 Sep;84(7-8):963-70. doi: 10.1007/BF00227411.
Six progeny trials that included 147 half-sib progenies of maize (Zea mays L.) population ESALQ PB-5 were conducted for the purpose of studying plot size and its consequences in recurrent selection programs. The progenies were evaluated in three 7x7 duplicate simple lattice experiments using one-row plots of 5 m(2). At harvest each plot was partitioned into five sub-plots (sampling units), and data was collected from each sampling unit. At the same time and place the same progenies were evaluated in three 7x7 duplicate simple lattice experiments using 1-m(2) (linear row with 5 plants) plots. Data were collected for plant and ear height, ear diameter, total ear weight, and total grain yield. The data were combined by using adjacent sampling units, and the analyses were performed by considered five plot sizes in addition to those of the independent trials with 1-m(2) plots. The experiments with 1-m(2) plots were less efficient in discriminating for yield traits among progenies than those with 5-m(2) plots. The combination of plot size and number of progenies evaluated indicated that an optimum plot size for yield was between 3 and 4 m(2), or 15-20 plants per plot. With such sizes the expected gain was maximized for the four replications used in this study. If the total area covered by each progeny is constant, the maximum gain from selection, however, is attained by decreasing plot size and increasing the number of replications. The minimum size of plots is, however, limited by practical or theoretical criteria. Plot size affected the estimates of additive genetic variance, coefficient of heritability, and genetic coefficient of variation for all of the traits. No practical limitation was observed for conducting experiments with 1-m(2) plot.
六个后代试验包括了 147 个玉米（Zea mays L.）种群 ESALQ PB-5 的半同胞后代，目的是研究小区大小及其在反复选择计划中的后果。后代在三个 7x7 重复简单格子试验中进行评估，使用 5 m² 的单行小区。在收获时，每个小区被分为五个亚区（采样单元），并从每个采样单元收集数据。同时和同地，同一批后代在三个 7x7 重复简单格子试验中使用 1 m²（5 株的线性行）小区进行评估。收集植物和耳高、耳径、总穗重和总粒重的数据。数据通过使用相邻的采样单元进行组合，分析除了使用 1 m² 小区的独立试验外，还考虑了五个小区大小。使用 1 m² 小区的试验在区分后代的产量性状方面效率低于使用 5 m² 小区的试验。小区大小和评估的后代数量的组合表明，产量的最佳小区大小在 3 到 4 m² 之间，或每个小区 15-20 株。在本研究中使用的四个重复中，这样的大小使预期增益最大化。如果每个后代所覆盖的总面积保持不变，那么通过减小小区大小和增加重复次数，可以获得最大的选择增益。然而，小区的最小尺寸受到实际或理论标准的限制。小区大小影响了所有性状的加性遗传方差、遗传力系数和遗传变异系数的估计值。在进行 1 m² 小区的试验时，没有观察到实际限制。
