Perennial flax (Linum spp.) breeding objectives at the University of Minnesota (UMN) are to develop agronomic (oilseed, fiber) and horticultural (cut flower, garden perennial) varieties that are hardy in Minnesota (USDA Plant Hardiness Zones 3 and 4). The objective of this research was to determine the range of cold hardiness in UMN perennial flax breeding populations compared with wild accessions of L. austriacum, L. lewisii, and L. perenne. Fifty-three genotypes from seven populations were low temperature acclimated, followed by controlled freezing using a programmable freezer. The observed lethal temperature for 50% plant kill (LT₅₀) ranged from >0 °C (0% survival) to <−12 °C (100% survival), for the test temperatures of 0, −4, −8, −10, and −12 °C. Cold damage was measured after 4 wk of regrowth as the proportion of alive shoots and a root damage rating. Significant negative correlations were observed between LT₅₀ and proportion of alive shoots (r = −.918) and root damage rating (r = −.935). Both L. austriacum and L. perenne had significantly less cold damage than L. lewisii and the breeding populations. This study establishes methods of screening perennial flax cold tolerance that are more cost effective, rapid, and repeatable compared to field evaluations.

中文翻译：

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控制冷冻研究作为多年生亚麻耐寒性的推论选择方法

明尼苏达大学 (UMN) 的多年生亚麻 ( Linum spp .) 育种目标是开发明尼苏达州耐寒的农艺（油籽、纤维）和园艺（切花、多年生花园）品种（美国农业部植物抗寒区 3 和 4） . 本研究的目的是确定 UMN 多年生亚麻繁殖种群与L. austriacum、L. lewisii和L. perenne的野生种质相比的抗寒性范围。来自 7 个种群的 53 种基因型进行了低温驯化，然后使用可编程冷冻机进行控制冷冻。观察到 50% 植物杀死的致死温度（LT ₅₀) 范围从 >0 °C（0% 存活）到 <-12 °C（100% 存活），测试温度为 0、-4、-8、-10 和 -12 °C。在再生 4 周后测量冷损伤作为活芽的比例和根损伤等级。_{在 LT 50}与活芽比例 ( r  = -.918) 和根损伤等级 ( r = -.935)之间观察到显着的负相关 。L. austriacum和L. perenne的冷害明显低于L. lewisii和繁殖种群。本研究建立了筛选多年生亚麻耐寒性的方法，与现场评估相比，这些方法更具成本效益、快速和可重复性。