甜瓜白粉病抗性數量性狀基因座定位

Mapping quantitative trait loci of powdery mildew resistance in melon (Cucumis melo L.)

劉地寬(Di-Kuan Lew)

指導教授 ： 胡凱康

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202002482

摘要

白粉病 (Podosphaera xanthii) 為臺灣甜瓜栽培上的重要病害。根據病害檢定及全基因體關聯性分析的結果判斷種原的抗病性，選擇3個抗病親本與2個感病親本雜交產生3個F2分離族群 (A6, B2, C4)，以雙限制酶系統建立分子標誌進行白粉病生理小種1 (race 1) 的抗性數量性狀基因座 (quantitative trait loci, QTL) 定位。
A6族群偵測到位於第2條染色體的QTL，其外表型變異解釋率 (phenotypic variance explained, PVE) 為93.59%；B2族群偵測到位於第5條染色體的QTL，PVE為80.12%；C4族群分別於第5及第12條染色體偵測到QTL，PVE分別為33.04%與34.68%，兩者之間有顯著的交感效應。本研究所偵測的QTL對於生理小種1的抗性皆可能與鄰近的抗性基因群有關，而根據前人研究QTL可能對臺灣另一個主要的生理小種5 (race 5) 具有抗性，後續可利用與抗性QTL連鎖的標誌以分子標誌輔助選拔進行臺灣甜瓜的抗病育種。

關鍵字

甜瓜 ； 白粉病生理小種1 ； 數量性狀基因座定位 ； 全基因體關聯性分析 ； 分子標誌輔助選拔

並列摘要

Powdery mildew is an important fungal disease caused by Podosphaera xanthii, affecting the yield and quality of melon in Taiwan. Three biparental F2 populations (designated as A6, B2 and C4) derived from crosses between resistant and susceptible parents (selected according to genome wide association study results) were used to identify quantitative trait loci (QTL) for powdery mildew (P. xanthii race 1) resistance in melon.
For the A6 population, one major QTL conferred powdery mildew resistance was identified on chromosome 2 with a phenotypic variance explained (PVE) of 93.59%, while another major QTL located on chromosome 5 was identified in the B2 population, with a PVE of 80.12%. In C4 population, QTL was identified on chromosome 5 and 12 in which PVE equals to 33.04% and 34.68%, respectively, with a significant interaction between them. The resistance of these QTLs to race 1 might be related to the proximity of resistance gene cluster and they have been shown to confer resistance to race 5 which is another important race in Taiwan. In future, markers linked to these QTLs could be utilized in marker assisted selection to facilitate the breeding of resistant melon cultivar in Taiwan.

並列關鍵字

Melon ； powdery mildew race 1 ； quantitative trait loci mapping ； genome wide association study ； marker assisted selection

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