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首页> 外文学位 >Early testing of Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) for Swiss needle cast tolerance.
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Early testing of Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) for Swiss needle cast tolerance.

机译：道格拉斯冷杉（Pseudotsuga menziesii var.menziesii（Mirb。）Franco）的早期测试对瑞士针头铸造的耐受性。

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摘要

The relationship between the level of Phaeocryptopus gaeumannii (Rohde) Petrak colonization and severity of Swiss needle cast (SNC) symptoms, the possibility of early testing of Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) for SNC tolerance, and geographic variation in coastal Oregon with respect to SNC tolerance were investigated.; Comparisons between the amount of P. gaeumannii DNA and SNC symptom severity (i.e., degree of yellowing or loss of needles) of 6 wind-pollinated Douglas-fir families (two families for each of three disease severity groups) in two progeny test plantations revealed that there were no immune Douglas-fir trees; infection and colonization of Douglas-fir needles by P. gaeumannii occurred at similar rates in the different disease severity groups. The presence of significant differences in symptom severity among the groups, therefore indicated that tolerance, rather than resistance, is responsible for the observed variation in disease symptoms. The degree to which a tree retains its last four growing season's needles appears to be a useful measure for assessing tolerance to SNC.; Trees from 55 wind-pollinated Douglas-fir families were assessed for SNC symptoms in two 2-year-old (juvenile) and two 10- and 12-year-old (mature) progeny tests to investigate the genetics of SNC tolerance in Douglas-fir and the possibility of early testing. Natural inoculation was found to be suitable for early testing purposes. Traits related to SNC tolerance (i.e., needle retention, needle color, foliage color and foliage density) were under low to moderate genetic control (0.11 ≤ h2i ≤ 0.37) at both ages. Moderate genetic correlations between juvenile and mature trees for needle color ( r2B = 0.53) and needle retention ( r2B = 0.75) make these traits suitable for early selection. Early selection for needle retention in seedlings is expected to be as efficient as selection in older trees for improving needle retention in older trees, while early selection for needle color is estimated to be 52% as efficient as later selection for needle color.; Two-year-old progeny of 152 wind-pollinated Douglas-fir families originating from the Siuslaw National Forest were assessed for severity of SNC symptoms in two seedling trials to investigate genetics of SNC tolerance and relationships between SNC tolerance of families with climatic and geographic variables of mother tree locations. The locations ranged between 25 and 667 m (mean = 331 m) in elevation and between 1 and 48.9 km (mean = 15.2 km) in distance to the Pacific Ocean. The southernmost and the northernmost mother tree locations were north of Florence and south of Pleasant Valley, respectively. Tolerance to SNC was found to be weakly heritable. Despite a wide range among families in severity of SNC symptoms, no significant relationships were observed between needle retention and geographic and climatic variables at mother tree locations. Foliage color in SNC infected trees, however, was significantly associated, although weakly (R2 = 0.14), with geography; with greenest foliage in families originating from lower elevations, southerly aspects and midway in the west-east transect across the Coast Range Mountains (i.e., greenest at about 20 km from the coast). The lack of strong patterns of SNC tolerance may be because geographic variation in SNC infection is limited within this region or because there has not yet been sufficient selection pressure on Douglas-fir for patterns to evolve.
机译： Phaeocryptopus gaeumannii （Rohde）Petrak定植水平与瑞士针铸（SNC）症状的严重性，道格拉斯冷杉（ Pseudotsuga menziesii ）早期检测的可能性之间的关系var。 menziesii [Mirb。] Franco）对SNC耐受性的研究，以及俄勒冈州沿海地区相对于SNC耐受性的地理变化。 P量之间的比较。两个子代试验人工林的6个风铃花道格拉斯冷杉科（三个疾病严重程度组各两个）的gaeumannii DNA和SNC症状严重程度（即泛黄或针刺程度）显示没有免疫的道格拉斯杉树； P对道格拉斯冷杉针的感染和定植。 gaeumannii 在不同疾病严重程度组中的发生率相似。各组之间症状严重程度的显着差异表明，耐受性而非耐药性是造成所观察到的疾病症状变化的原因。树木保留其最后四个生长季节的针的程度似乎是评估对SNC耐受性的有用方法。在两个2岁（幼龄）和两个10岁和12岁（成熟）子代测试中评估了55个风铃花道格拉斯冷杉科的树木的SNC症状，以调查道格拉斯-SNC耐性的遗传冷杉和早期测试的可能性。发现自然接种适合于早期测试。与SNC耐受性相关的性状（例如，持针量，针的颜色，叶子的颜色和叶子的密度）处于低至中等的遗传控制下（0.11≤ h 2 i < / inf> ≤0.37）。幼树和成熟树之间针叶颜色（ r 2 B = 0.53）和针头保留度的中等遗传相关性 r 2 B = 0.75）使这些特征适合早期选择。预计尽早选择幼苗中的针头与提高老树中针头的保留率在老树中的选择一样有效，而对针色的早期选择估计比以后对针色的选择效率高52％。在两项幼苗试验中，对来自Siuslaw国家森林的152个风铃花粉红色道格拉斯冷杉家庭的两岁后代进行了SNC症状的严重程度评估，以调查SNC耐性的遗传学以及气候和地理变量家庭的SNC耐性之间的关系树的位置。这些位置的高程范围为25至667 m（平均331 m），距太平洋的距离为1至48.9 km（平均15.2 km）。最南端和最北端的母树位置分别在佛罗伦萨以北和普莱森特山谷以南。发现对SNC的耐受性较弱。尽管家庭中SNC症状的严重程度差异很大，但在母树位置，针头保持与地理和气候变量之间没有发现显着的关系。然而，受SNC感染的树木的叶子颜色与地理显着相关，尽管弱（R 2 = 0.14）。其家庭中最绿的树叶来自海拔较低，偏南的地方以及横跨海岸山脉的东西方样带的中途（即最绿的距离海岸约20公里）。缺乏强大的SNC耐受模式可能是由于该区域内SNC感染的地理差异有限，或者是由于道格拉斯冷杉尚无足够的选择压力来演变模式。

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