秈稻幼苗耐寒性之近似同源系育成與數量性狀基因座探勘

Breeding of indica near-isogenic line with seedling cold tolerance and exploration of QTLs associated with cold tolerance at the seedling stage in rice

劉祐廷(Liu, Y. T.) ； 王聖善(S. S. Wang) ； 陳榮坤(R. K. Chen)

《臺南區農業改良場研究彙報》 76期 (2020/12) Pp. 25-36

摘要

秈稻耐寒性不佳，於臺灣地區一期作秧苗期容易遭遇低溫而發生寒害，造成農民嚴重損失。為改善秈稻幼苗耐寒性，本研究建立幼苗耐寒性外表型篩選模式，以幼苗耐寒性良好的臺稉9號作為貢獻親，利用回交育種法育成臺中秈17號幼苗耐寒性近似同源系（near-isogenic line）NSY1051070號，其農藝性狀與臺中秈17號相似，且成功改善幼苗耐寒性。本研究進一步利用臺中秈17號、臺稉9號與NSY1051070號作為試驗材料進行次世代定序分析，利用獲得之高密度單一核苷酸多型性（single nucleotide polymorphism, SNP）分子標誌，進行幼苗耐寒性之數量性狀基因座（quantitative trait locus, QTL）的探勘，結果顯示NSY1051070號帶有來自臺稉9號的8個染色體置換區間，此8個區間為NSY1051070號幼苗耐寒性潛在QTLs，可作為水稻幼苗耐寒性之基因定位及分子標誌開發的基礎，將有助於國內秈稻品種幼苗耐寒性之改良。現有技術：回交育種法育成優良品種的近似同源系，改善其缺陷性狀。創新內容：開發幼苗耐寒性的潛力分子標誌，提升育種選拔效率。對產業影響：有助於改善國內秈稻品種幼苗耐寒性，降低農民生產風險。

關鍵字

水稻 ； 幼苗耐寒性 ； 次世代定序 ； 分子標誌

並列摘要

Indica rice (Oryza sativa L.) is sensitive to low temperature. Low temperature stress is common for the rice seedlings of first crop, and caused enormous yield loss in Taiwan. To improve the cold tolerance of indica rice seedlings, a screening model for the cold tolerance phenotype at the seedling stage was established in this study. We selected the japonica cultivar Taiken 9 (TK9) as the donor parent for its seedling cold tolerance, and used backcrossing breeding to breed a near-isogenic line of indica cultivar Taichung Sen 17 (TCS17), NSY1051070, which is cold-tolerant at the seedling stage. The agronomic traits of NSY1051070 are similar to TCS17, but it is more cold-tolerant than TCS17 at the seedling stage. Then we used TCS17, TK9 and NSY1051070 to do next-generation sequencing (NGS), and developed high-density single nucleotide polymorphism (SNP) markers for exploration of quantitative trait locus (QTL) associated with cold tolerance at the seedling stage. The results showed that NSY1051070 was with eight potential QTLs associated with seedling cold tolerance from TK9. These results may become the basis for the mapping of rice seedling cold tolerance genes and for the development of molecular markers of rice seedling cold tolerance, and it can help to improve the seedling cold tolerance of indica varieties in Taiwan. What is already known on this subject? Backcross breeding is an effective method to breed the near-isogenic lines of elite variety and improves its defect. What are the new findings? We developed potential molecular markers of seedling cold tolerance, improved the efficiency of breeding selection. What is the expected impact on this field? The results in this study contribute to improve seedling cod tolerance of indica variety in Taiwan, and allow farmers to reduce risks of production.

並列關鍵字

Rice ； Seedling cold tolerance ； Next-generation sequencing ； Molecular marker