控制水稻穀粒長、穀粒寬、抽穗期、株高與穗長之數量性狀基因座的遺傳定位

Abstract

水稻穀粒外型、抽穗期、株高與穗長是決定稻米品質、產量與分布之重要因子。本研究以147個（133個InDel與14個SSR）分子標記分析由台稉2號與台中秈10號雜交產生的286株F2族群，建立包含12條染色體之連鎖群圖譜，並進行控制榖粒長、穀粒寬、抽穗期、株高與穗長之QTL定位。從F2族群的外表型分布可觀察穀粒外型變異均在兩親本內，而其他農藝性狀的變異範圍皆出現超越親本的現象，且穀粒長與寬之間的相關係數只有0.09。定位結果說明控制穀粒長與穀粒寬的QTL分別有10個與8個，控制穀粒長的QTL中位於第1、3與7條染色體上的QTL之外表型變異的解釋量 (Phenotypic Variance Explained, PVE) 均超過10 %以上，且台中秈10號的對偶基因會使穀粒增長0.18 – 0.22 mm。控制穀粒寬的QTL中位於第2與5條染色體上的QTL其PVE高達12.0與44.8 %，而台稉2號的對偶基因會使穀粒變寬0.08 – 0.17 mm。控制抽穗期、株高與穗長的QTL分別各有3個、5個與4個，控制抽穗期的QTL中位於第3與10條染色體上的QTL其PVE約為26 %，當此2個QTL帶有台稉2號的對偶基因時會分別使抽穗期提早6.7天與延長6.3天。控制株高的QTL中位於第1條染色體上的QTL效應最大其PVE為52.5 %，帶有台稉2號的對偶基因時會使株高增加14.9公分。控制穗長的QTL中位於第8條染色體上的QTL效應最大其PVE為10.1 %，帶有台稉2號的對偶基因會使穗長增加1.5公分。 從本研究的定位結果中與前人研究比較發現，控制穀粒寬的QTL可能是GW5，位於第10條染色體上控制抽穗期的QTL可能是Ehd1，而位於第1條染色體上控制株高的QTL可能與低腳烏尖的半矮性基因sd-1相同，需要進一步的確認與前人研究的基因序列比對才能確認，並且這些定位結果可作為未來水稻MAS上的利用。

Rice grain shape, heading date, plant height and panicle length are the most important factors affecting rice grain quality, yield and adaption area. To detect QTLs controlling grain length (GL), grain width (GW), heading date (HD), plant height (PH), and panicle length (PL), we evaluated two hundred and eighty six F2 individuals derived from the cross between Taiken 2 (TK2) and Taichung Sen 10 (TCS10). Through genotyping all the F2 population, we construct a linkage map with 147 molecular markers including 133 InDel and 14 SSR markers covering all 12 chromosomes in this study. The phenotypic ranges of grain trait in F2 population were between two parents, but the other traits showed transgressive segregation. The correlation between GL and GW are only 0.09. The result of QTL mapping shows that there are 10 and 8 QTLs controlling GL and GW. The PVE of QTLs controlling GL on chromosome 1, 3, 7 are all above 10 %, and GL would increase 0.18 – 0.22 mm by carrying TCS 10 allele. The PVE of QTLs controlling GW on chromosome 2 and 5 are 12% and 44.8%, and GW would increase 0.08 mm and 0.17 mm by carrying TK2 allele. A total 3 QTLs for HD, 5 QTLs for PH and 4 QTLs for PL. The PVE of QTLs on chromosome 3 and 10 controlling HD are around 26%. While these two QTLs carrying TK2 allele, the HD would earlier 6.7 days and delay 6.3 day. The QTL controlling PH on chromosome 1 is the major QTL explained 52.5% of the total variation of PH, and it would increase 14.9 cm with TK2 allele on it. The QTL of PL on chromosome 8 has the largest PVE and would increase 1.5 cm while carrying TK2 allele. Compare all these result with previous study, the QTL of GW on chromosome 5 might be the GW5 gene, and the QTL controlling HD on chromosome 10 would be Ehd1. The QTL at the long arm on chromosome 1 might be the same as sd-1. All these assumption need to be confirm by functional markers or sequence alignment. All these information would be useful to the rice breeder or have practical used through MAS in rice.