水稻全染色體置換系之族群模擬與選育研究

Simulation and Development Study of Whole Chromosome Substituted Lines on Rice

吳東鴻(Dong-Hong Wu) ； 王群山(Chun-Shan Wang) ； 胡凱康(Kae-Kang Hwu)

《作物、環境與生物資訊》 14卷3期 (2017/09) Pp. 141-152

https://doi.org/10.30061/CEB.201709_14(3).0001

摘要

我國水稻栽培品種大多係稉稻遺傳背景，為有效導入秈稻或野生稻等其他優良農藝性狀基因，提高國內稻作產量潛能與逆境耐性，選育一套稉稻背景之秈稻全基因體置換系族群，作為台灣稉稻分子輔助選育效益之評估平台，便於完整探討目標性狀之堆疊效應以及與環境交感影響，有助於提高融合亞種間優良基因之效率。在規劃染色體置換系族群的最佳選拔策略前，以所估算完整染色體條件機率進行模擬研究，探討各世代最低族群數與試驗效率，模擬結果顯示在BC_1F_1世代涵蓋全套完整染色體貢獻親染色體的最小族群數為60株，但若進一步考量輪迴親恢復率，各置換系由BC_1F_1至BC_3F_1世代中，依序篩檢160、150與120株後裔時，整體資源最終均可讓每染色體置換系達到99%背景恢復率，之後在BC3F2世代，99%信心水準下最長染色體的品系需700株、最短者僅需97株可獲得固定之同質結合全染色體置換系。將以上模擬規劃套用於實務上，育成秈稻'Habataki'在稉稻「台農71號」背景的全染色體置換系，12個秈稉稻染色體置換系上最低的輪迴親恢復率為98.9%，顯示可透過上述各世代模擬條件，瞭解選育亞種或跨物種間染色體置換系族群之最佳選拔策略。

關鍵字

水稻 ； 全染色體置換系 ； 選拔策略

並列摘要

Whole chromosome substitution lines (WCSLs) carrying introgression from elite indica variety, Habataki, in japonica cultivar, Tainung71, were developed as a breeding material to improve the grain yield potential and stress tolerance. Prior to conducting the marker-assisted backcrossing (MABC) scheme, a simulation study was used to determine the minimum population size for the risk of failure, defined as losing any whole chromosome during selection. Meanwhile, we evaluated the relationship between population size and recurrent parent genome (RPG) recovery, and simulate the expected RPG under certain realistic condition for the breeding program. The simulation results indicated the minimum BC_1F_1 population size should have at least 60 individuals to avoid losing any whole chromosomes from donor parent at 1% risk level. Given the population size of BC_1F_1, BC_2F_1 and BC_3F_1 generations was set at 160, 150 and 120, respectively, the RPG recovery rate may achieve up to 99% by the end of MABC. Subsequently, the advanced backcross lines with the longest chromosome would have to screen 700 plants and the shortest one 97 plants for a 99% confidence level to obtain homozygous substitution lines at the BC3F2 generation. In the actual program of developing WCSLs, the backcrossed progenies derived from the indica-japonica cross of 'Tainung71' and 'Habataki' were selected and the lowest RPG recovery rate of final WCSLs is 98.9% which approximate the simulation result.

並列關鍵字

Oryza sativa L. ； Selection strategy ； Whole chromosome substituted line