應用分子輔助回交選育稉稻多粒數品系之探討

Study on Development of Japonica Breeding Lines Introgressed High Grain Number Gene through Marker-Assisted Backcross Approach

賴明信(Ming-Hsing Lai) ； 李長沛(Charng-Pei Li) ； 卓緯玄(Woei-Shyuan Jwo) ； 顏信沐(Hsing-Mu Yen) ； 胡凱康(Kae-Kang Hwu) ； 吳東鴻(Dong-Hong Wu)

《台灣農業研究》 65卷1期 (2016/03) Pp. 31-44

https://doi.org/10.6156/JTAR/2016.06501.04

摘要

賴明信、李長沛、卓緯玄、顏信沐、胡凱康、吳東鴻。2016。應用分子輔助回交選育稉稻多粒數品系之探討。台灣農業研究 65(1):31–44。水稻粒數屬於數量性狀且無法於生育早期進行選拔，並需透過重複性田間試驗才能估計選拔效應；對此，為了加強秈、稉稻間的產量基因聚合效率並驗證目標基因座的效益，本試驗利用分子輔助回交法，將多粒數對偶基因(Ha-Gn1)由秈稻‘Habataki’導入國內具有良好食味的稉型稻「台農71號」(‘Tainung 71’ or ‘TNG71’)中，藉以評估該基因在台灣品種背景下之產能效益。近同源系選育過程中，分別使用位在Gn1基因座旁6個連鎖標幟作為前景選拔使用，另背景選拔共分析152個SSR與InDel標幟使其標幟間距可達10.8 cM。基因型分析結果顯示，除了第1號染色體短臂上帶有Gn1基因座約30 cM的長度外，該BC3F2後裔台農71號Gn1品系(TNG71-Gn1)已大多回復為「台農71號」的遺傳背景；而該植株的外觀農藝性狀，舉凡抽穗期、穗數與株高等均與輪迴親「台農71號」相似，僅每穗粒數較「台農71號」提升了26%，由105.2 (± 37.4)增加為133.1(± 61.9)粒。此外，另採用「台農71號」第1號染色體階層片段置換系，進一步觀察同在第1條染色體短臂區域上的粒數基因中Gn1a、Gn1b基因座與其2次枝梗數基因座qSBN1對於穗形結構與穎花數的關係。結果顯示，Gn1a多粒數基因座並不影響1 次枝梗粒數，主要係提升2次枝梗粒數且增加2次枝梗平均粒數，而非全面性提升每穗所有枝梗上的粒數。另上游區間Gn1b基因座，則係影響2次枝梗數，使得每穗粒數增加。藉此亦顯示，2次枝梗數基因座qSBN1可細分為2個子基因座，對2次枝梗數的影響分別在兩親本間可達38.4%與11.7%。上述成果，將有助稻作產能相關聚合育種以及穗形結構之選育基礎，應用分子輔助育種提升我國稻作產能。

關鍵字

水稻 ； 粒數 ； 分子輔助回交 ； 產量

並列摘要

Lai, M. H., C. P. Li, W. S. Jwo, H. M. Yen, K. K. Hwu, and D. H. Wu. 2016. Study on development of japonica breeding lines introgressed high grain number gene through marker-assisted backcross approach. J. Taiwan Agric. Res. 65(1):31-44. Rice grain number, a quantitative trait, is difficult to be selected in early generations and needs to be evaluated its genetic gain number based on replicate filed trials during breeding procedure. In order to improve the introgressed efficiency of grain yield related genes and validate QTL effect between japonica-indica cross, this study introduced the high grain number gene, Gn1, from ‘Habataki’ (indica type) into ‘Tainung71’ (‘TNG71’), a japonica cultivar with high eating quality, to assess the yield potential of the near-isogenic lines through marker-assisted backcross approach. The development of near-isogenic lines used 6 flanking markers of Gn1 locus for foreground selection and 152 SSR and InDel markers with an average of 10.8 cM for background selection. Genotyping assay showed that one BC3F2 plant (TNG71-Gn1) has completely recovered the recurrent ‘TNG71’ genome except a 30 cM segment harboring Gn1 on the short arm of chromosome 1. TNG71-Gn1 had the same heading date, panicle number, and plant height as the recurrent parent, ‘TNG71’, while TNG71- Gn1 had higher grain number per panicle than ‘TNG71’. In addition, four ‘TNG71’ stepped aligned inbred recombinant lines different from their introgressed chromosmal region harboring Gn1 gene on chromosomal 1 were developed in order to investigate the relationship among Gn1a, Gn1b, and qSBN1 loci for genetic effects on rachis branch and spikelet number. Genetic analysis showed that Gn1a locus increased secondary branch number and average grain number of secondary branch, but not average grain number of primary branch. Gn1b locus, which located in upstream region, would be beneficial on second branch number resulting in increased grain number. The qSNB1 locus consisted of two sub-loci and explained 38.4% and 11.7% of the difference in the second secondary branch number between ‘Habataki’ and ‘TNG71’, respectively.

並列關鍵字

Oryza sativa L. ； Grain number ； Marker assisted backcross ； Grain yield