Abstract Hybrid poplar clonal growth in the states (regions) of Minnesota (MN), Indiana (IN), Michigan (MI), and New York (NY) USA was analyzed to discover 10 geographically robust (geo-robust) clones, all P. deltoides x P. nigra (D x N) hybrids previously tested and screened in MN, that were broadly adapted across latitudinal and longitudinal ranges of 9 and 20 degrees, respectively. The clonal effect for growth explained 25 to 36 % of the total variance, 2.5–4.1 times the clone x site interaction. Clone explained 24 to 46 % of total variation in canker occurrence on two sites. Genetic gain in growth was calculated relative to commercial check clones. Genetic gain in growth of geo-robust clones exceeded that of random clones by 24 to 44 %. Geo-robust clones and the best clones on each site were not significantly different on the MN sites, but best clones outperformed geo-robust clones on the other sites by 10 to 39 % genetic gain. Geo-robust clones grew faster than commercial check clones on all but the MI site. The reduction in genetic gain for growth due to using broadly adapted clones relative to the best clones has to be compared to the additional costs and benefits of multiple breeding zones.

中文翻译：

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地理上健壮的杂种杨树无性系的发现

摘要 分析了美国明尼苏达州 (MN)、印第安纳州 (IN)、密歇根州 (MI) 和纽约 (NY) 等州（地区）的杂交杨树无性系生长，发现了 10 个地理上健壮（geo-robust）的无性系，所有. deltoides x P. nigra (D x N) 杂种先前在 MN 中进行了测试和筛选，它们分别在 9 度和 20 度的纬度和经度范围内广泛适应。克隆对生长的影响解释了总方差的 25% 到 36%，是克隆 x 位点相互作用的 2.5–4.1 倍。Clone 解释了两个地点溃疡发生总变异的 24% 到 46%。相对于商业检查克隆计算生长的遗传增益。地缘强健克隆生长的遗传增益比随机克隆高 24% 至 44%。Geo-robust 克隆和每个站点上的最佳克隆在 MN 站点上没有显着差异，但最好的克隆在其他站点上的表现优于地理稳健性克隆 10% 到 39% 的遗传增益。除了 MI 站点外，地理鲁棒克隆的增长速度都快于商业检查克隆。由于使用广泛适应的克隆相对于最佳克隆而导致的生长遗传增益的减少必须与多个育种区的额外成本和收益进行比较。