(57(3):193-204)Screening Technique for Salt Tolerance in the Rice Seedling Stage

本試驗以水稻台農67號經疊氮化鈉化學誘變純化之突變庫中之品系爲材料，以1/2改良式木村氏水耕液外加150mMNaCl進行秧苗期耐鹽性篩選；試驗結果顯示，大部份品系在鹽分逆境處理後5-7天與第11-14天間產生兩個劇烈轉折變化，鹽害指數由原先較低的情形快速昇高，顯示此兩個時間點對於大部份參試品系耐鹽性具有重要影響。本試驗除成功建立水稻秧苗期對於鹽分逆境傷害反應基礎資料及篩選程序外，並發現台農67號突變庫不同品系之秧苗期耐鹽性表現變異度很大，選取秧苗期對於鹽分逆境具耐、感性的水稻突變品系各8個進行農藝性狀調查結果顯示，所篩選耐鹽性突變品系之農藝性狀均有較佳表現，顯示此種篩選技術可適用於育種程序中後代品系選拔，成功建立後代快速篩選技術，將可應用於耐鹽性水稻品種改良。Seedlings obtained from a chemical mutagenized Tainung 67 mutant population were conducted for the salt-tolerance in a hydroponic system containing 150mM NaCl. The effect of salinity was recorded by salt injury score according to the severity of damage after salt treatment. Most of the mutant lines exhibited two drastic increases in salt injury score at day 5 to 7 days and 11 to 14 days that indicated these two time periods having critical influence on the plant's response to salt. In this study, we developed an effective technique for screening salt-tolerant mutants and obtained manifold fundamental data for salt responses at seedling stage. A high degree of variation in salt response was found among the Tainung 67 mutant lines. Agronomic characteristics of eight Salt-tolerant and eight salt-sensitive lines were further investigated. The results showed that salt-tolerant lines had better agronomic performance than those salt-sensitive lines. This revealed that the rapid screening system is valid. This technique will be useful for the application of breeding salt-tolerant rice