水稻幼苗耐冷性數量性狀基因座之定位

Abstract

低溫冷害為影響水稻產量的主要因素之一，以在水稻幼苗期與孕穗期所遭受到的傷害最為嚴重。本研究的目的為採用較具耐冷性之稉稻品種臺農67號與不具耐冷性之秈稻品種臺中在來一號所雜交所得之243個重組自交系，進行水稻幼苗耐冷性之數量性狀基因座定位。水稻幼苗的耐冷性分別以幼苗存活率與人為訂定的幼苗耐冷等級測量值表示。研究結果顯示幼苗存活率與幼苗耐冷等級的外表型相關係數達到0.50，兩種外表型所定位到的數量性狀基因座都位於第六條與第十一條染色體上相同的區間，分別與分子標記RC6-1與RC11-11連鎖。幼苗存活率的數量性狀基因座命名為qCTSS6.1與qCTSS 11.1，而幼苗耐冷等級的數量性狀基因座則命名為qCTS6.1與qCTS11.1。幼苗存活率或幼苗耐冷性的兩個數量性狀基因座綜合的效應都能解釋將近30%遺傳定位族群內的外表型變異。

Rice grown in temperate areas is subjected to chilling stress at seedling and booting stages. The purpose of this thesis was to identify quantitative trait loci (QTLs) for chilling tolerance at the seedling stage of rice, using 243 recombinant inbred lines derived from a cross between a chilling-tolerant japonica cultivar, TNG67, and a chilling-sensitive indica cultivar, TN1. The phenotypes of chilling tolreance at seedling stage was scored by the measurements of the survival rate and the artifical chilling-tolerant classes. The results showed that the correlation coefficient between the survival rate and the artifical chilling-tolerant classes was 0.50. Both phenotypic measurements identified two major QTLs on the same chromosomal region: one on chromosome 6, the other on the chromosome 11. The former QTL linked to the SNP marker RC6-1, and the latter QTL linked to the SNP marker RC11-11. The QTLs for the survival rate under chilling stress were named qCTSS6.1 and qCTSS11.1, and the QTLs for the chilling-tolerant classes were named qCTS6.1 and qCTS11.1 The combined effects of the two QTLs were able to explain approximately 30% of phenotypic varions within the genetic mapping population, for either the survival rate or the chilling-tolerant classes.