Genetic variation of Fraxinus excelsior half-sib families in response to ash dieback disease following simulated spring frost and summer drought treatments
Genetic variation of Fraxinus excelsior half-sib families in response to ash dieback disease following simulated spring frost and summer drought treatments
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模拟春季霜冻和夏季干旱处理后白蜡树半同胞家族响应白蜡枯萎病的遗传变异
DOI：
10.3832/ifor1514-008
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
R. Bakys
中科院分区：
文献类型：
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作者：
A. Pliūra;Vaidotas Lygis;D. Marčiulynienė;V. Suchockas;R. Bakys
摘要：在人工控制的环境中，研究了来自立陶宛两个种群的10个优良白蜡（Fraxinus excelsior）半同胞家系对白蜡枯梢病的反应，检测了遗传变异和遗传力的变化，并估计了人工春霜和夏旱处理后的基因型与环境互作和表型可塑性。2014年，每种处理和对照（不处理）使用一批200棵四年生白蜡幼苗。健康状况，芽冲洗物候和高度进行了评估，每个幼苗，和疾病的发病率和存活率进行了评估，每个家庭之前（在开始的植被季节）和治疗后（在结束的植被季节）。发病率从0.77-0.80上升到0.90-0.95。树木死亡率在一个植被季节显着降低霜冻处理（21%）比干旱处理（25%）或对照（31%）。供试的F.尽管在发病率和损害率方面的显著的家系间差异表明基因作用的加性模式和因此对疾病的数量抗性，但Excelsior家系对白蜡枯梢病是完全抗性的。无论是疾病的发病率，也没有树的健康状况评分显着不同的应用程序的治疗（包括控制），表明在一般情况下，可以忽略不计的影响，模拟的不利条件对健康状况的灰苗。但对发病率、枯梢长度和树体存活率的影响，G×E互作显著（P > 0.05），表明白蜡树家系对枯梢病的易感性对环境条件的依赖程度不同，说明受试家系的可塑性和反应规范在不同环境（处理）间存在遗传变异。霜冻和干旱处理后健康状况的加性遗传变异系数和遗传力与对照相比均显著增加，表明模拟胁迫条件可能显著影响供试F.在抗性性状方面，可以更好地评价不同家系的表现，进行有效的抗性家系选择，并获得显著的遗传增益。
Abstract: Ten juvenile Fraxinus excelsior half-sib families from two Lithuanian populations have been tested in the controlled environment for their response to ash dieback disease caused by Hymenoscyphus fraxineus, detecting changes of genetic variation and heritability, as well as estimating genotype by environment (G×E) interaction and phenotypic plasticity following artificial spring frost and summer drought treatments. In 2014, a batch of 200 four-year-old ash seedlings was used for each treatment and control (no treatment). Health condition, bud flushing phenology and height were assessed for each seedling, and disease incidence and survival ratios were assessed for each family both before (at the beginning of the vegetation season) and after the treatments (at the end of the vegetation season). Disease incidence ratio increased from 0.77-0.80 up to 0.90-0.95. Tree mortality rates during one vegetation season were significantly lower in the frost treatment (21%) than in the drought treatment (25%) or control (31%). None of the tested F. excelsior families were completely resistant to ash dieback, although significant among-family differences in disease incidence and damage rates suggest an additive mode of gene action and thus a quantitative resistance to the disease. Neither disease incidence rates, nor tree health condition scores differed significantly among the applied treatments (including control) indicating in general a negligible effect of the simulated adverse conditions on health status of the ash seedlings. However, G×E interaction was found to be significant (at P > 0.05) for disease incidence, length of necrotic shoots and tree survival, implying that susceptibility of ash families to the dieback disease unequally depends on environmental conditions, and indicating a presence of genetic variation in plasticity and reaction norms of the tested families across environments (treatments). Substantially increased coefficients of additive genetic variation and heritability in health condition following both frost and drought treatments and compared to control showed that simulated stress conditions may noticeably contribute to expression of differences among the tested F. excelsior families in their resistance traits, thus enabling a better evaluation of performance of different families, an effective family selection for resistance, and achievement of a marked genetic gain.