為探討荔枝果實發育過程酸甜口感成份之質量變化，調查‘台農6號’、‘台農2 號’與‘玉荷包’荔枝果實生育過程之圜藝性狀。果實發育過程，三個荔枝品種果重增加趨 勢，均呈現S型生長曲線。‘台農6號’為3-4 g的大子品種，著果後第8週果肉才明顯增 長。‘台農2號’為小子品種，平均種子重1 g以下，‘玉荷包’為高焦核(chicken - tongue seed) 比例品種，種子平均重量低於0.5 g。‘台農2號’與‘玉荷包’皆於著果後第6週，果肉即開 始增長，成熟果實之果肉率較‘台農6號’高。‘台農6號’於著果後第11週可滴定酸仍有 0.5%，此時果皮鮮紅美觀，花青素與葉綠素含量比值接近5，但果實酸度偏高，待著果後 第12與13週可滴定酸降至0.3%與0.2%時，果皮色澤較偏棗紅色時適口性較佳，為合 宜之採收成熟度。三個品種可溶性固型物含量於中果期即已達18-20°Bnx，品種間差異不 大。果實酸甜口感主要由有機酸的含量所控制，其中又以蘋果酸為主。‘台農6號’的蘋果 酸含量顯著高於‘玉荷包’與‘台農2號’。‘台農2號’的蘋果酸含量最低，為本試驗中糖酸 比最高的品種。而‘玉荷包’糖酸比介於兩品種之間，口感甜中帶酸。

Tn order to investigate the composition of sour and sweet substances during the tfuit development of lychee, we recorded the horticultural traits of the development of lychee varieties Tainung No.6, Tainung No.2 and Yu-Her-Pau. The results showed that the fruit weight increase of these three varieties was analogous to S- type growth curve. Tainung No. 6 was a large-seeded variety with average seed weight of 3 to 4 grams, and its arils began to grow 8 weeks after fruit setting. Tainung 2 is a small-seeded one with average seed weight less than 1 gram and Yu-Her-Pau is in high propm1ion of chicken-tongue seeds. The average seed weight of both varieties was less than 0.5 grams, and arils of both began to grow 6 weeks after fruit setting, while the aril rate of mature fruits was higher than that of Tainung No.6. The titratable acidity (TA) of Tainung No.6 fruit was 0.5% at 11 weeks after fruit setting, with the peel being bright red, and the ratio of anthocyanin to chlorophyll content was close to 5, but the acidity of fruits was high. At the 12th to 13th week after fruit setting, the peel color turned into burgundy and became more suitable for harvest with the TA declined to 0.2 to 0.3%. The total soluble solids (TSS) of three varieties could reach 18 to 20 °Brix in the middle fruit stage, but there was no significant TSS difference between these varieties. The sweet and sour taste of the fruit was mainly determined by the content of organic acids. Malic acid was the main composition of organic acid, and the malic acid content of Tainung No.6 was significantly higher than that of Yu-Her-Pau and Tainung No.2, with Tainung No.2 being the lowest. This made Tainung No.2 the highest sugar-to-acid ratio variety in this test, and that of Yu-Her-Pau was between the other two varieties.