Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/65633
標題: 杉木對於葉枯病抗病感病之遺傳統計學研究
Statistical Genetic Study of the Resistance/Susceptibility of China Fir (Cunninghamia lanceolata) to Leaf Blight Pathogen (Pestalotiopsis shiraiana)
作者: 吳立德
Wu, Li-Te
關鍵字: 香杉
China fir(Cunninghamia lanceolata var. konishii)
杉木葉枯病
早期測試
人工接種
遺傳率
抗病篩選
相關性
勝算比
邏輯斯蒂迴歸
leaf blight of China fir
early testing
artificial inoculation
heritability
resistance selection
correlation
odds ratio
logistic regression
出版社: 森林學系
摘要: 台灣的香杉(Cunninghamia lanceolata var. konishii)經常受到杉木葉枯病的危害,是幼苗時期與生長後期的重要病害之一,其中以幼苗至七、八年生的造林木,在潮濕多雨的季節時最易受害。引起杉木葉枯病之病原菌為白井擬盤多毛菌(Pestalotiopsis shiraiana P. Henning),屬於一種不完全真菌。 本研究的樹種來源是採自台灣東勢林區管理處出雲山的香杉種子園,園區共有25個無性系,代表香杉在台灣全島的遺傳變異。我們採集全部25個風媒授粉的單親家系種子,分別在幼苗萌芽後五個月、七個月、九個月及13個月時在出雲山溫室內進行早期測試。在人工接種前量測其生長性狀,於接種一個月後調查苗木發病的情形。 在生長性狀方面,經由變方分析表的結果顯示,四個時期在環境條件上並無顯著差異,家系之間和區集與家系的交感效應則是呈現顯著差異(P<0.001)。各個生長性狀的遺傳率估計值頗高,顯示在家系之間可以進行早期選拔,但是多數生物量的遺傳率有超過1.0的情形。 在感病性狀方面,以「感病等級」進行分析所得的結果不明顯,而無法有效的挑選出抗病的家系;以「整體有無病斑」進行分析,其結果顯示在家系之間是有差異的存在(P<0.001),能夠以此標準區分抗病與易感病的家系;另外以「罹病度」進行分析,可以發現家系之間呈現顯著差異(P<0.001)。另外,以兩種分級方式計算罹病度比較分級方式是否會造成結果的不同,而研究中兩種分級方式所得到的罹病度大致差異不大。以罹病度所得的遺傳率,七個月時為0.221(±0.029),九個月為0.400(±0.047),13個月時為0.926(±0.073)。 將生長性狀與感病性狀進行相關分析,分析結果在區集之間會有相異的結果,使得而結果顯著性不高。苗高在五個月時有與罹病度成反比的趨勢,而後三個時期則是呈現正相關的傾向。根徑則是在初期與罹病度有正向相關的趨勢,而後期則是略呈負相關的傾向。這個結果顯示香杉的早期抗病遺傳篩選須慎選適當 的時期,因為一年生幼苗的各個時期表現的生長與抗病感病反應有所不同 實驗中用感病的二元數據以邏輯斯蒂迴歸對於香杉家系與感病情形建立一預測模式,從模式中分別預測在苗木五到13個月,以不同的家系種植組合的感病機率。 總括來說,實驗結果顯示以不同感病評比標準對於結果會造成影響,因而需要選擇正確的判斷標準。另外,感病性狀在苗木生長初期有頗高的遺傳率,利於進行早期選拔。而感病的可能機率也藉由邏輯斯蒂迴歸建立的模式來加以預測。
China fir (Cunninghamia lanceolata var. konishii) was often attacked by leaf blight, a common disease which attacks then species form seedlings in nursery to saplings in the plantation. Plantations at ages 7~8 are particularly susceptible. The causal agent of disease was isolated and identified as Pestalotiopsis shiraiana P. Henning, an imperfect fungus. The seeds were collected in Dong-Shi China fir seed orchard. 5, 7, 9, 13-month -old greenhouse-grown seedlings of 25 open-pollinated China fir families were measured growth traits and artificially inoculated with leaf blight fungus. After inculcated 1 month, we investigate the disease spots. For growth traits: Analysis of variance (ANOVA) results showed that most of time environment of greenhouse has no significant difference (P>0.05) and families and GE interaction are significant difference (P<0.001) in four growth stages. The estimates of narrow-sense heritability were high for growth traits which implies large between families variation. Thus early selection was feasible, but some of heritability are unreasonable exceed 1.0. For disease-resistance traits: three symptom traits (classification of spots area, spotted or not, and susceptibility degree) has been recorded. The result of classifications of spot area showed none significant different between families. Other two traits showed significant results (P<0.001, P<0.001). In this research, we defined two kinds of classifications by sum of spots in each seedling to calculated susceptibility degree. The result showed that different classification has no strong effect to susceptibility degree. The estimates of individual narrow-sense heritability in 7, 9, 13-month-old seedlings were 0.221 (0.029), 0.400 (0.047), 0.926 (0.073), respectively. The phenotype correlations between growth traits and disease-resistance traits showed different results between two blocks. The correlation between height and susceptibility degree was negative trend in first stage and positive trend in other three stages. The correlation between root diameter and susceptibility degree was positive trend in primary stages and negative trend in later stages. In this research, we also use logistic regression to analyze the binary data of disease to predict the infection probability with different combinations of families at four growth stages. In general, results demonstrated that different kinds of resistance/susceptible classification would effort the decision of selection. In addition, China fir seedlings have high heritability of resistance and growth and that is favorable to proceed the early selection, and the infection probability can be predicted by logistic regression.
URI: http://hdl.handle.net/11455/65633
Appears in Collections:森林學系

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