| Summary: | 碩士 === 國立臺灣大學 === 園藝學研究所 === 89 === Summary
A chilling tolerant “Line 85022” of angled loofah selected by Li(1999) was grown together with a popular cultivar, ‘San-C’ in the open field. cold weather in the autumn-winter season caused sever chilling injury for ‘San-C’. Mature leaves were more susceptible than young leaves. However, both young and mature leaves of line 85022 were resistant to the cold weather. Electrolyte leakage of ‘San-C’ rose from cotyledon growth stage to plant maturation stage with a peak at 75 days after sowing. Mature plant had a higher electrolyte leakage than seedling. Electrolyte leakage of “line 85022” rose only slightly from cotyledon stage to 61 days after sowing. The plant of 87 days after sowing had an electrolyte leakage much lower than the seedlings. On the other hand, adult plant of “Line 85022” had a higher chilling tolerance than seedling. The two cultivars (line) had a significant difference in chilling tolerance in the seedling stage. The critical temperature for causing chilling injury for “Line 85022” was 2 to 4℃ lower than that of ‘San-C’. When seedlings of both cultivars than exposed to low temperature and then returned to non-chilling temperature, “Line 85022” could tolerate 3 days longer low temperature than ‘San-C’. Seed germination test for both cultivars were carried out at 15℃ and 20℃ for 7 days. Germination rate for either cultivars was ＜ 50﹪. When un-germinated seeds of “Line 85022” were transferred from 15℃ to 25℃, germination rate reached 99﹪in 3 days However, ‘San-C’ with similar treatment had ＜ 50﹪ germination in 7 days. Although, the germination rates of both cultivars were low at ≤20℃. “Line 85022” seeds had higher rate and stronger seedling germination growth vigor than ‘San-C’ when the cold-treated germinating seeds were transferred to 25℃. The electrolyte leakage of the hybrid of ‘San-C’ × “Line 85022” was in between that of its parents. The regression between growth vigor and electrolyte leakages was r=0.375. The hybrid had fruit length and diameter of 48.55 and 8.26cm, slightly deep net vein on the surface, and no white spot. The hybrid also had fewer flowers under long day conditions. A back cross line of ‘San-C’ × “Line 85022” and ‘San-C’ was also made available for further genetic studies on chilling tolerance and fruit characters.
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