臺灣龍眼（Euphoria longana Lam.）品種果實性狀之變異

Variation of Fruit Characters among Longan (Euphoria longana Lam.) Varieties in Taiwan

調查臺灣52龍眼品種及部份品種於不同地區不同年份之果實性狀變異顯示各種果實性狀均受品種、地區、年份之影響，尤以果重最為明顯。調查107組樣品之果實性狀變異範圍如下，果色均為黃褐色，各品種有深淺之不同，部份帶有果粉；果肉半透明，淡白至淡黃之間；肉質有軟脆之分，以脆肉較多；種子色由紅褐至黑褐，以黑褐較多。成熟期自7月至10月，以8月最多；果重介於5.2至18.2公克之間，平均10.6公克，種子重介於0.5至2.5公克之間，平均1.8公克；果肉可溶性固形物含量在10.3%至26.0%之間，平均18.3%；果肉率在50.0%至70.8%之間，平均61.6%。果實大小和果重、果皮重、種子重、果肉重有顯著之正相關。粉殼為最主要之品種，其次為紅殼及青殼，其餘均少量栽培。目前龍眼栽培之主要問題為：1.需有不同成熟期、大果、豐產之品種以調節產期。2.植株矮化之方法。3.隔年結果之防止。4.每穗果數之控制，以免果實因結果太多而變小。

The variation of fruit characters among 52 longan varieties at different locations and years in Taiwan was investigated. Most fruit characters studied were affected by different varieties, locations, and years. The effect was most significant in fruit weight. The variation of fruit characters of 107 samples measured was as follows. The fruit is light to dark yellow-brown. The aril is translucent white to light yellow. The seed is red brown to black-brown. The mature season was from July to October. Most were harvested in August. Fruit weight ranged from 5.2 to 18.2 grams (mean=10.6 g). Seed weight ranged from 0.5 to 2.5 grams (mean= 1.8 g). Soluble solids in aril ranged from 10.3 to 26.0% (mean=18.3%). Aril ratio in fruit ranged from 50.0 to 70.8% (mean=61.6%). Fruit size was significantly related to fruit weight, peel weight, seed weight and aril weight. The cultivar Feng Ko accounts for more than 80% of longan production in Taiwan. It is followed by Hong Ko and Ching Ko. Current problems confronting longan culture in Taiwan are:1) needs of varieties with large fruit, high yield and various mature season, 2) control of plant height to lower cost of management,3) methods to control irregular bearing, and 4) methods of thinning to control fruit number per cluster.