探討導入乾旱產量相關QTL 對稉稻台南11號直播適應性之影響

Abstract

直播水稻系統具節省水資源與勞力的特點，是面對氣候變遷、水資源減少與農業勞動力缺乏的一種栽培模式。乾旱產量相關基因座 (qDTYs) 能在乾旱下促進深根與提高水分利用效率，被認為具有提升直播適應性的潛力。本研究導入qDTY 2.1、qDTY 3.1、qDTY 1.1, 3.1、qDTY 1.1, 2.1, 3.1、qDTY 3.2 、qDTY 2.2, 4.1 、qDTY 12.1 評估對台南11號直播適應性的影響。幼苗期 qDTYs 導入系株高高於台南11號，並影響根系形態，其中 qDTY2.2, 4.1 與 qDTY12.1 可提升地上部生長勢，qDTY3.1 與 qDTY1.1, 3.1 除幼苗期水分利用效率較佳外，在移植、濕式與乾式直播系統中水分利用效率也優於台南11號。在乾式直播環境中qDTY3.1 與 qDTY1.1, 3.1氣孔密度較低，且在乾式直播幼苗期具發育良好的根系，使其幼苗生地上部乾重較佳。在低滲透壓下qDTY3.1 與 qDTY1.1, 3.1發芽率高於台南11號，且qDTY3.1 根系延長最明顯。轉錄體分析顯示，低滲透壓下qDTY3.1 與 qDTY1.1, 3.1提高對 ABA 敏感的抗旱基因表現，單獨導入 qDTY3.1 效果尤為明顯，且胺基酸與氮利用相關基因亦同。本研究顯示qDTY3.1 與 qDTY1.1, 3.1可提升水分利用效率與乾式直播下根系結構，具有提升親本直播適應性之潛力。

Direct-seeded rice (DSR) is a cultivation method that addresses climate change, water scarcity, and labor shortages through reduced water and labor input. Drought-yield quantitative trait loci (qDTYs), which enhance deep rooting and improve water use efficiency (WUE) under drought stress, have the potential to increase the adaptability of rice to DSR. In this study, qDTY2.1, qDTY3.1, qDTY1.1, 3.1, qDTY1.1, 2.1, 3.1, qDTY3.2, qDTY2.2, 4.1, and qDTY12.1 were introgressed into TN11 to evaluate their effects on adaptability under DSR. At the seedling stage, most qDTY lines exhibited greater plant height and changed root morphology compared to TN11. Among them, qDTY2.2, 4.1 and qDTY12.1 enhanced shoot vigor, while qDTY3.1 and qDTY1.1, 3.1 showed superior WUE not only at the seedling stage but also under transplanted, wet-DSR, and dry-DSR (DDS). Under DDS, these lines exhibited lower stomatal density and well-developed root systems during seedling stage, contributing to increase shoot dry weight. Under low osmotic treatment, they showed higher germination rates, with qDTY3.1 displaying the most pronounced root elongation. Transcriptome analysis revealed upregulation of drought-responsive genes related to ABA sensitivity, particularly in qDTY3.1, along with genes involved in amino acid metabolism and nitrogen utilization. These results suggest that qDTY3.1 and qDTY1.1, 3.1 enhance WUE, and specifically improve root structural development under DDS conditions, indicating their potential to increase the adaptability of recurrent parent to direct seeding systems.