ABSTRACT

To clarify the factors affecting the level of spring frost damage in seed orchards of pine wood nematode (PWN)-resistant Pinus thunbergii, we investigated the frost damage to the female strobili of 13 PWN-resistant P. thunbergii clones in an experimental crossing garden during the spring of 2020. Monthly air temperatures from January to March 2020 were higher than the corresponding temperatures in the previous six years, whereas the temperatures in April 2020 were lower compared to the previous years. The number of female strobili on the upper and lower branches of the trees averaged 4.7 and 2.7, respectively. The spring frost damaged 6% and 22% of the strobili on the upper and lower branches, respectively. A generalized linear mixed model analysis confirmed that this difference was significant; moreover, it showed significant clonal variation in the female strobili mortality. The mortality risk to the female strobili of each clone was negatively correlated to the time required for the female strobili to bloom. Thus, the P. thunbergii clones with an early flowering phenology are more likely to suffer from spring frost damage.

摘要

为了澄清影响在松材线虫（PWN）耐药的种子园弹簧冻害水平的因素黑松，我们调查了霜冻损害到阴球花13 PWN抗性的黑松2020 年春季在实验杂交花园中克隆。 2020 年 1 月至 3 月的月气温高于前六年的相应温度，而 2020 年 4 月的气温低于前几年。树木上、下枝上的雌性鹧鸪数平均分别为4.7和2.7只。春季霜冻对上、下枝条的破坏率分别为 6% 和 22%。广义线性混合模型分析证实这种差异是显着的；此外，它显示出雌性 strobili 死亡率的显着克隆变异。每个克隆的雌性 strobili 的死亡风险与雌性 strobili 开花所需的时间呈负相关。因此，P. thunbergii 具有早花物候的克隆更有可能遭受春季霜冻损害。