Successful field establishment begins with superior plant genetics, quality seeds, land preparation, sowing depth, weed control, and moisture. Our research examined the field-establishment plant density of six populations of little bluestem [Schizachyrium scoparium (Michx.) Nash] and three selection generations at three locations over a 3-yr period. Recurrent selection was used to develop C₁ and C₂ populations from six improved C₀ populations (NU1, NU2, UC1, UC2, UO1, and UO2). In Cycle 1, open-pollinated seeds from each C₀ population were geminated in water of −0.8 MPa potential for 7 d. For each C₀ population, seeds that germinated in 7 d were selected to create six C₁ populations. Cycle 2 selection was identical to Cycle 1, except that C₁ populations were used to create the six C₂ populations. Plant density (number of plants m^‒2) was determined using a frequency grid method at 30, 60, and 90 d after planting (DAP). The plant density of little bluestem varied with location (L), population (P), selection generation (G), DAP, L × P, L × G, P × G, and L × DAP interactions (P < .01). Averaged over generations and DAP, plant density averaged 7.6, 6.6, 6.5, 7.1, 6.6, and 7.1 plants m^‒2 among populations NU1, NU2, UC1, UC2, UO1, and UO2, respectively. Averaged over populations and DAP, plant density averaged 5.9, 6.6, and 8.2 plants m^‒2 for generations C₀, C₁, and C₂, respectively. Thus, recurrent selection for increased laboratory seed germination in simulated dry conditions results in greater establishment plant densities of little bluestem.

中文翻译：

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在模拟干燥条件下选择用于改善实验室种子萌发的小蓝茎种群的田间建立

成功的田间种植始于优良的植物遗传学、优质种子、整地、播种深度、杂草控制和水分。我们的研究检查了 3 年期间三个地点的六个小蓝茎 [ Schizachyrium scoparium (Michx.) Nash]种群和三个选择世代的田间建立植物密度。循环选择用于从六个改进的 C ₀种群（NU1、NU2、UC1、UC2、UO1 和 UO2）中开发 C ₁和 C _2种群。在第 1 周期中，来自每个 C ₀种群的开放授粉种子在 -0.8 MPa 电位的水中萌发 7 天。对于每个 C ₀种群，选择在 7 d 内发芽的种子产生 6 个 C₁人口。循环 2 选择与循环 1 相同，不同之处在于使用 C ₁种群来创建六个 C ₂种群。在种植后 30、60 和 90 天 (DAP) 使用频率网格法确定植物密度（植物数量 m ^{-2 ）。}Little bluestem 的植物密度随位置 (L)、种群 (P)、选择世代 (G)、DAP、L × P、L × G、P × G 和 L × DAP 相互作用而变化 ( P  < .01)。对世代和 DAP 进行平均，植物密度在种群 NU1、NU2、UC1、UC2、UO1 和 UO2 中平均分别为 7.6、6.6、6.5、7.1、6.6 和 7.1 株 m ^{-2 。}对种群和 DAP 进行平均，植物密度平均为 5.9、6.6 和 8.2 个植物 m ^‒2分别为 C ₀、 C ₁和 C ₂代。因此，在模拟干燥条件下增加实验室种子发芽率的反复选择导致小蓝茎的建立植物密度更大。