Abstract:

Sugar and acid contents were determined in two progeny populations (Early Star×Zaolupantao and 94-1-40×Early Red Ⅱ) in 2004 and 2005 in order to study the relationship of fruit shape (flat peach/peach), hairs on fruit epidermis (peach/nectarine) and flesh color (white / yellow ) with sugar and acid contents. Sucrose is predominant at maturity, followed by reducing sugars (glucose and fructose) and in smaller amounts by sorbitol. The main acids are malic acid, citric acid and quinic acid, while shikimic acid accounts for 0.3% of total acids. Sucrose, total sugar and soluble solids contents were significantly higher in flat peaches than peaches, while no significant difference was found in glucose, fructose, citric acid and shikimic acid contents between flat peaches and peaches. The difference in malic acid and quinic acid contents between flat peaches and peaches varied with year. Nectarines had significant higher malic acid and total acid contents than peaches, and did not show significant difference in citric acid,quinic acid and shikimic acid contents with peaches. Glucose, total sugar and soluble solids contents were significantly higher in nectarines than peaches in 2005, so was sorbitol contents in 2004. There were no significant difference in sugars, soluble solids and acids contents between white-flesh and yellow-flesh genotypes.

Key words: flat peach, peach, nectarine, flesh color, sugar, acid