滲調與披衣處理對洋桔梗種子發芽及抽苔之影響

Effects of Priming and Pelleting on Seed Germination and Bolting of Eustoma grandiflorum

臺灣近年代工外銷許多洋桔梗[Eustoma grandiflorum (Raf.) Shinn.]切花至日本，國內已可生產F1雜交種子，種子滲調可能降低高溫引起之簇生與種子披衣以利自動播種等技術亟待建立。本研究取臺南區農改場育成之洋桔梗品系種子為材料，經處理後於25℃、光強度165 μmol·m-2·s-1 (photosynthetic photon flux density, PPFD)環境行發芽測試。以聚乙二醇8000 (polyethylene glycol-8000, PEG-8000)及CaCl2水勢各為-1.0及-1.5 MPa進行滲調處理3週後播種之#103-1種子發芽率均可達88% - 96%，且較未滲調處理者提前3天發芽。種子滲調後之實生苗抽苔率以後續栽培於25/20℃高於30/25℃，且以經滲調者之抽苔率較高。洋桔梗#103-1未披衣種子經5-30℃貯藏12個月後之發芽率仍可達92% - 100%。以-1.0 MPa之PEG-8000、-1.0及-1.5 MPa之CaCl2滲調處理3週之種子經5℃貯藏6個月後之發芽率均可維持在89% - 95%；但以-1.5 MPa之PEG-8000處理再貯藏6個月後發芽率降低至76%。以行政院種苗改良繁殖場研發之配方(TSSB4-1+TSSB1-1)，將洋桔梗#341種子進行披衣膜衣處理製成不同粒徑大小(0.5-2.1 mm)進行發芽測試，結果顯示未披衣種子與粒徑在0.5-1.29 mm披衣膜衣處理者皆於播種後5天發芽，且其發芽率無顯著差異。粒徑>1.3 mm者，隨粒徑增加使種子較晚發芽、發芽係數遞減、達最大發芽時間及T10與T50遞增。

Taiwan has introduced foreign cultivars of lisianthus [Eustoma grandiflorum (Raf.) Shinn.] in recent years and has exported a large amount of cut flowers to Japan. Domestic F1 hybrid seed production is currently feasible, which would increase international competitiveness. It is urgent to establish the techniques of seed priming to reduce possible heat-induced rosette and seed pelleting to facilitate automatic sowing. F1 seeds bred by Tainan District Agricultural Research and Extension Station were treated and sown at 25℃ under 165 μmol·m-2·s-1 conditions. Osmopriming with polyethylene glycol-8000 (PEG-8000) and calcium chloride (CaCl2), at -1.5 MPa and -1.0 MPa for three weeks resulted in 88% to 96% germination of unstored #103-1 seeds. Primed seeds germinated significantly earlier than unprimed seeds by three days. Seed priming increased subsequent bolting percentage in seedlings grown at 30/25℃, as compared to the unpriming control. Seed germination percentage ranged from 92% to 100% after the naked #103-1 seeds stored at 5-30℃ for 12 months. After storage at 5℃ for 6 months, germination percentage remained 89% to 95% in seeds primed with -1.0 MPa PEG-8000 or -1.0 and -1.5 MPa CaCl2, but reduced to 76% germination in seeds primed with -1.5 MPa PEG-8000. Moreover, various sizes (0.5-2.1 mm) of lisianthus #341 seeds were pelleted and film-coated by using the formula (TSSB4-1+TSSB1-1) developed by Taiwan Seed Improvement and Propagation Station. Results showed that germination was not altered by pelleted seeds with 0.5-1.29 mm or smaller sizes. For pelleted seeds >1.3 mm, germination percentage and coefficient reduced and time to germination increased with increased pelleted size.