探討控制水稻抽穗日數基因與播種期之交感

Interaction between Genes Controlling Days to Heading and sowing dates in Rice

石瀞予(Ching-Yu Shih)

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(2018年)

https://doi.org/10.6342/NTU201800314

摘要

水稻的抽穗日數為影響產量的重要農藝性狀之一，不同品種因地理環境與栽培期作培育出最合適的抽穗日數以達到最佳產量。抽穗日數由多個效應不同的基因控制，有些基因與環境因子如日長及溫度具有交感效應。本試驗利用台稉2號與台中秈10號的雜交後RILs，評估兩個播種期與四個功能性分子標誌Ehd1、Ehd4、Ghd7與Dth8基因與環境之間的交感作用，亦建構連鎖圖譜偵測在此族群中是否存在其他控制抽穗日數的QTL。
分別對兩個播種期做多重迴歸分析，其中Ehd1、Ehd4與Dth8顯著影響兩個播種期抽穗日數的變異，Ghd7只在較早播種期下顯著表現。在較早播種期下Ehd1:Ghd7:Dth8與較晚播種期下Ehd1:Dth8基因間交感統計上顯著。將兩個播種期與合併的多重迴歸分析中，播種期為影響抽穗日數變異最大的因子，其外表型解釋變異為54.46%，除了在兩個播種期分別做多重迴歸分析結果得到的基因與基因交感效應，Ehd4和Ghd7與播種期之間具有交感效應。QTL分析與多重迴歸分析結果差異不大，除了51.52 cM上的Ghd7外，在78 cM上多偵測到qHD7，推測此區間可能含有一個以上的基因，需要進一步利用染色體片段置換系驗證此觀察結果。在不同環境下評估基因表現有利於後續分子標誌輔助選種之應用，穩定表現的基因適用於廣泛區域的育種，與環境間具有交感的基因則可應用在特定地區品種之培育。

關鍵字

水稻 ； 抽穗日數 ； 多重迴歸分析 ； QTL定位

並列摘要

Heading days is one of the important agronomic traits for seed production in rice. Rice cultivars have been bred to adapt to various environments and cropping systems in terms of optimum flowering time to maximize the grain yield. Heading days in rice is controlled by multiple quantitative genes, and some of these genes may have effects that interact with environmental factors such as photoperiod and temperature. In this study, we evaluated the heading days of a RILs population derived from a cross between Taiken 2 and Taichung Sen 10 under two sawing dates, and genotypes of four previously found heading days controlling genes Ehd1, Ehd4, Ghd7, and Dth8 via functional markers to evaluate the interaction between genes and environments. We also constructed a genetic linkage map for this population to determine if there are other QTLs controlling heading days.
When analyzed separately, the results of multiple regression analysis showed that Ehd1, Ehd4 and Dth8 significantly affected heading days in both environments, while the effect of Ghd7 was only statistically significant in the early sawing date. Genetic interactions of Ehd1:Ghd7:Dth8 and Ehd1:Dth8 were statistically significant in the early and late sawing date, respectively. When the heading days under both sawing dates were combined, the results of multiple regression analysis indicated the sawing date is the largest contributor to the phenotypic variance (54.46%). Besides the genetic effects and interactions found in the separated analysis, Ehd4 and Ghd7 were found interacting with sawing dates. The result of QTL analysis was largely consistent with the multiple regression analysis except that gHD7 position at 78.00 cM of chromosome 7 was mapped instead of the Ghd7 located at 51.52 cM, suggesting that there may be more than one genes at chromosome 7 controlling heading days. Further study using chromosome segment substitution lines may be needed to verify this supposition. Evaluating genetic effects in different environments can contribute to marker assisted selection. Steadily detected genes can be used in general environments; however, genes having interactions with environments could be used for varieties developed for a certain sawing date.

並列關鍵字

Oryza sativa L ； Heading days ； multiple regression ； QTL mapping

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