水稻台農67號疊氮化鈉突變庫突變體之篩選：米粒外觀及直鏈性澱粉突變體

Abstract

本試驗以疊氮化鈉誘變所建立之台農67號突變庫已純化之1，120個M7世代突變品系為材料，進行米粒外觀及直鏈性澱粉含量突變體之篩選，結果發現突變品系之白米率及完整米率之突變範圍分別為44~81%及0~78%。突變親台農67號之穀粒外穎及種皮為無色，米粒呈透明，透明度中等，部份米粒有腹白，極少數有心白發生。經誘變後發現有完全心白、完全腹白及不同程度之乳白粒突變體出現，部分品系透明度增加，呈晶瑩剔透狀，但也有很多品系變成似糯性之不透明色。突變後米粒直鏈性澱粉含量分佈範圍從糯性至31%，變異範圍明顯廣大，且呈連續分布。而具有相同直鏈性澱粉含量之突變品系其農藝性狀、千粒重、結實率及米粒型態也呈現相當大之變異。利用糙米橫切面碘液染色，可快速分辨糥性與非糯性突變體、乳白米與糯米突變體，然而所分離的糥性突變品系間，仍有部分直鏈性澱粉合成之差異存在。總之，疊氮化鈉誘變劑誘導水稻台農67號產生許多碾米品質、米粒外觀及直鏈性澱粉含量差異之突變體，提供同一米質多樣性變異之資源，可直接評估其利用性或作為探討澱粉合成之機制及影響米質之相關生理生化特性之材料，提供改進米質與產量之參考。 In this paper, we report the screening of grain appearance and amylose content from 1,120 mutants in M7 generation of a mutation pool derived from TNG67 rice variety induced by sodium azide mutagenesis. The results show that the range of variations in milled rice rate and head rice rate are 44-81% and 0-78%, respectively. The grains of TNG67 variety show colorless husk and seed coat, middle translucent and partial white-belly, mutants colored husks and seed coats, high translucent, all white-belly, milk-white and transparent grains are observed. The grain amylose content of mutants shows continuous distribution to 31%. Mutants with similar amylose content possess various grain characteristics in 1000-grain weight, grain filling rate and morphological shape. Grain cross-section staining with iodide could be applied to differentiate the waxy mutant from non-waxy, milk-white, and waxy-pigmented mutants. These grain mutants provide good materials for rice food processing and starch metabolism studies, and germplasms for rice variety and quality improvement.