Inheritance of Flower Form and Color, Seed Production ex vivo and Seed Treatments of Lisianthus

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A better understanding of inheritance of flower form and color in lisianthus [Eustoma grandiflorum (Raf.) Shinn.] would facilitate breeding efficiency. This study aimed to test pollination timing and the technique of seed production by cut immature capsule was examined in Eustoma. Further, seed treatments would advance the industry. The flower traits of progenies in 41 crosses were measured among inbred Eustoma, which were selfed 5-6 generations in Tainan District Agricultural Research and Extension Station. Results showed that flower diameter of the progenies ranged from medium (5.1-5.9 cm) to large (≧6.0 cm) sizes. Double flower is dominant to single flower. Cyanic color is dominant to acyanic color, picotee color is dominant to single color, green color is dominant to white color, pink color is dominant to white color, and purple color is dominant to pink color. Results showed the fruit set percentage was higher than 90% after pollination with various flower age. Length and width of fruit in Eustoma #103-1 increased rapidly between 15 days after pollination (DAP), fruit fresh weight (FFW) significantly increased between 10 and 30 DAP, when seed water content was about 15%. FFW did not increase while seed water content reduced to 5% after 40 DAP. Seed coat appeared golden at 50 DAP and became dark brown at 60 DAP. Effects of thermal conditions during vase, weeks after pollination, and harvested seeds from fruit with 30 cm or fruit only on subsequent bolting and growth were also studied. Results showed that seed harvested from fruit with 30 cm or fruit only at 4-8 weeks after pollination (WAP) at vase during 25oC could reach more than 90% germination. And significant lower germination was observed for seeds harvested from fruit only at 2 WAP. Seed germination percentages were significantly lower when harvested fruit with 30 cm or fruit only at vase during 10oC, while only those at 6 WAP had higher germination percentage than other maturity. Seeds from 4, 6, and 8 WAP at vase during 25oC, and from 6 WAP at vase during 10oC were sown and grown at 30/25oC or 25/20oC. Results showed that bolting percentage was higher, regardless of weeks after pollination, harvested from fruit with 30 cm or fruit only, and temperatures during vase, at 25/20oC than at 30/25oC. Eustoma #103-1 seeds harvested from fruit with 30 cm shoot at 4 WAP and vase temperature during 25oC had higher bolting percentage under 30/25oC than other treatments. Harvested from fruit only at 6 WAP and vase temperature during 10oC had higher bolting percentage under 30/25oC than fruit with 30 cm shoot. Effect of temperature (5 oC and 25/20 oC) and light intensity (0, 195, and 365 µmol.m-2.s-1) during seed imbibition was studied on bolting percentage in lisianthus seedlings grown at 25/20 oC or 30/25 oC. Results showed lisianthus ‘Umihonoka’ grown under 30/25 oC had higher bolting percentage after the seeds were imbibied at 5 oC than 25/20oC. The highest bolting percentage was recorded in those under 365 µmol.m-2.s-1 during imbibition at 5 oC. Osmopriming with polyethylene glycol (PEG) and calcium chloride (CaCl2), at -1.5 MPa and -1.0 MPa for three weeks resulted in germination percentage of 90%, and primed seeds emerged significantly earlier than nonprimed seeds. Bolting percentage was significantly higher in those after primed for three weeks than nonprimed plants under 30/25 oC. Seed longevity of primed Eustoma #103-1 seed was also measured. Results indicated primed seed germination with -1.5 MPa of PEG-8000 decreased after 6 months storage. Moreover, lisianthus seeds were drum coated into pellets with various sizes (0.5-2.1 mm) and film coating by using formula (TSSB4-1+TSSB1-1) developed by Taiwan Seed Improvement and Propagation Station. Results indicated the larger pelleted size (>1.7 mm) significantly reduced the germination and germination coefficient but significantly increased germination timing. Effects of storage temperature (5-30oC) and duration (0, 6, 12 months) on germination and time to maximum germination of Eustoma #103-1 were studied. Results showed that seed germination rate was higher than 90% after storage for 12 months. Seed germination decreased with prolonged storage duration.