清酒用稻米性狀及抽穗期之基因定位

Mapping QTLs of Grain Traits and Heading Date in Sake-Brewing Rice

連苡廷(Yi-Ting Lien) ； 許龍欣(Lung-Hsin Hsu) ； 李杏芳(Hsing-Fang Lee) ； 陳榮坤(Rong-Kuen Chen) ； 林順福(Shun-Fu Lin)

《作物、環境與生物資訊》 17卷3期 (2020/09) Pp. 124-143

https://doi.org/10.30061/CEB.202009_17(3).0003

摘要

由於臺灣常有稻米生產過剩的問題，水稻育種計畫逐漸轉為重視品質及多元用途，因此開發水稻酒米品種為新的育種目標之一。本研究以臺灣稉稻品種台南16號與日本酒米品種美山錦做為雜交親本，建立F_2及F_(2:3)族群，以進行釀酒相關性狀及與引種適應性相關之抽穗期等重要性狀的基因座定位，並且探討其遺傳機制。結果顯示，本研究在兩個期作下共偵測到13個QTL與心白性狀相關，其中第3條染色體頂端之qWCE3-1與qWCS3-1為不同期作下穩定調控心白表現的主效QTL，解釋主要的心白外表型變異。然而，僅在一期作中偵測到第4條染色體上大效應之qWCE4-2，為侷限在此環境下作用之基因。這些主效基因為來自美山錦之等位基因時，可提高心白表現。千粒重則定位到10個相關的QTL，其中兩期作均可偵測到第3條染色體之qGWt3-1及第9條染色體之qGWt9-1表現，但兩者效應方向相反，為不同親本提供增加千粒重表現之等位基因。抽穗日數則在不同期作中偵測到3對相同位點之QTL，效應均為正值。其中以qDTH10-1能解釋最多外表型變異，當此QTL為台南16號的同型結合時，在二期作可以延長約12天的抽穗期。本研究也利用QTL緊密連鎖之4個分子標誌，進行基因型篩選，集結酒米重要性狀之基因及臺灣品種之晚抽穗基因，共選拔出21個具有晚抽穗、大心白及大粒種之品系，期望能育成適合臺灣環境栽培之酒米品種。本研究之QTL定位及遺傳分析結果亦可作為未來酒米品種育種之參考。

關鍵字

酒米 ； 數量性狀基因座定位 ； 心白 ； 抽穗期 ； 粒重

並列摘要

Since it has been a problem of rice overproduction in Taiwan, some rice breeding programs are gradually changed to focus on quality and diverse applications. Thus, developing new sake-brewing rice varieties becomes one of the new breeding goals. The purpose of this study was to identify quantitative trait loci (QTL) associated with traits desirable for sake-brewing, including white core size rate (WCS), white core expression rate (WCE), and 1000-grain weight (GWt), as well as days to heading (DTH) involved in the adaption of rice introduction. In two crop seasons, we analyzed genetic structure on F_2 and F_(2:3) populations derived from the cross between Tainan 16 (TN16), a Taiwanese japonica rice variety, and Miyamanishiki (Mi), a Japanese sake-brewing rice. The result of QTL mapping shows that there are thirteen QTLs associated with WCE and WCS in two crop seasons. qWCE3-1 and qWCS3-1 on the apical of chromosome 3 are the major QTLs regulating white core traits in both crop seasons, and qWCE4-2 on chromosome 4 is the major QTL for WCE especially in the l^(st) crop season. These three major QTLs carrying Mi allele would increase WCE and WCS. Moreover, there are ten QTLs associated with GWt. Two pairs of QTLs, qGWt3-1 on chromosome 3 and qGWt9-1 on chromosome 9, were detected in both crop seasons. However, they had oppositive effect indicating that alleles from different parents could contribute GWt. Three pairs of QTLs associated with DTH were detected in both crop seasons, and qDTH10-1 on chromosome 10 had major effect on the trait. When homozygous alleles of the qDTH10-1 are transferred from TN16 to a line, DTH would extend for about 12 days. Besides, twenty one F_(2:3) lines were selected by using four SSR markers linked with QTLs related to sake-brewing. These lines with traits, including late heading date, big white core, and heavy grain weight, are expected to become new rice varieties for producing sake in Taiwan. The results of QTL mapping and genetic analysis would provide useful information for future breeding programs of sake-brewing rice.

並列關鍵字

sake-brewing rice ； QTL mapping ； white core ； heading date ； grain weight