多環境下水稻抽穗期與株高之數量性狀基因座定位

Abstract

抽穗期與株高是水稻相當重要的農藝性狀，此二性狀皆是由多對基因所調控的數量性狀，為瞭解各QTL 在不同環境中遺傳效應的變化，本試驗利用水稻品種臺稉2 號與臺中秈10 號的雜交後代263 個F2:4的家系在三個環境兩個期作中定位 QTLs。 利用多重區間定位法 (multiple interval mapping)，共定位到11 個與抽穗期有 關的基因座，分佈在第1 條、第2 條、第3 條、第4 條、第5 條、第7 條、第8 條與第10 條染色體上，各QTL 對抽穗期性狀的外表型變異解釋量為1.5 ~ 62.0 %； 定位到4 個與株高有關的基因座，分佈在第1 條、第2 條、第6 條與第10 條染色 體上，各QTL 對株高外表型變異的解釋量為1.7 ~ 49.9 %。控制兩性狀的基因效應 方向在親本內是分散的，因此後代重組產生的分離族群有表現超越親本分離的現 象。兩性狀的主效基因qHD10 與qPH1 在各環境間表現穩定；部分QTL 與環境產生交感，qHD3 在一期作的效應較二期作效應大；qHD8a 在臺北一期作相較於其他 定位到的環境有明顯的表現；其它定位到的QTL 皆為微效基因，易受環境影響導 致遺傳效應不穩定。 多重環境下定位QTL 可以進一步瞭解QTL 與環境的交感，將QTL 的遺傳效應區分為純遺傳效應和基因與環境交感效應，這是在單一環境定位QTL 所無法做到的。穩定表現的QTL 可以應用在廣泛區域的育種上，與特定環境具有交感或變 化一致的QTL 則可以在地區品種的育種上使用。在多環境下定位QTL 的結果，無論對於未來分子標誌輔助選種的評估，或是目標性狀導入優良品種，皆具有參考的價值。

Heading date and plant height are important agronomic traits in rice. Both traits are quantitative traits which are controlled by multiple genes. In this study, a rice F2:4 population consisting of 263 lines was derived from a cross between japonica variety Taiken 2 and indica variety Taichung Sen 10. The F2:4 population were grown in 3 location in 2 seasons to map QTL (quantitative trait loci). The stcitistical method to detect QTL is multiple interval mapping. The result showed, in heading date, totally 11 QTLs which distributed on chromosome 1, 2, 3, 4, 5 ,7 ,8 and 10. The phenotypic variation explained (PVE) of these QTL are 1.5 ~ 62.0 %. In plant height, 4 QTLs were detected and distributed on chromosome 1, 2, 6 and 10.The PVE of these QTL are 1.7% ~ 49.9 %. The genetic effects of QTLs in parents were dispersed, leading to transgressive inheritance. These results indicated that the genetic effect of major QTL,qHD10 and qPH1, were stable in different environments However some QTL were influenced by QTL × environment effect (QE effect). The genetic effect of qHD3 in the first season was stronger than the second season, and the genetic effect of qHD8a in Taipei in the first season was stronger than other environments. All the other QTLs were minor QTLs and their genetic effect were unstable in different environments. Mapping QTL under multiple environments could realize QE effect,and divided genetic effect into pure QTL effect and QE effect. In breeding program, the stable QTL could use in all environment, and the QTL which had QE effect could use for local variety. This study provided the information for marker assisted selection and marker assisted introgression.