Objective To study the genetic characteristics of sugar and acid content in mature fruits of selfing offspring fruit in Vitis amurensis Rupr. 'Shuangyou' and its hybrids 'Zuoyouhong' and 'Beibinghong'.

Methods The composition and content of sugar and acid in mature fruits from Vitis amurensis Rupr. 'Shuangyou' and its hybrids 'Zuoyouhong' and 'Beibinghong' were determined by high performance liquid chromatography (HPLC). The genetic characteristics of sugar and acid content in mature fruits from parents 'Shuangyou' 'Zuoyouhong' and 'Beibinghong' were analyzed.

Results Among the three tested Vitis amurensis Rupr. and its hybrids, the annual average total sugar contents of the parental 'Shuangyou' 'Zuoyouhong' and 'Beibinghong' were 197.2, 186.3 and 234.6 mg/g FW, respectively. The total sugar contents of their selfing offspring were 187.3, 215.4 and 186.8 mg/g FW. The content of soluble sugar and total sugar in the progenies of 'Zuoyouhong' self-crossing combination were higher than the mean values of the parents for two consecutive years. The average contents of glucose, fructose and total sugar in the self-crossed progenies of 'Shuangyou' and 'Beibinghong' were lower than parental lines. The annual average organic acid contents of the parental 'Shuangyou' 'Zuoyouhong' and 'Beibinghong' were 9.4, 8.0 and 8.8 mg/g FW, respectively. The organic acid contents of their selfing offspring were 7.2, 8.9 and 7.4 mg/g FW. The total acid content of the progenies of 'Zuoyouhong' was higher than the parental value, while the total acid contents of the progenies of 'Shuangyou' and 'Beibinghong' were lower than the annual average values of the parental lines.

Conclution The total sugar content of the progenies of 'Zuoyouhong' was higher than the parental value, with a high-parent plant rate of 84.3%, indicating a certain potential for over-parental genetic gain. The total sugar contents of the progenies of 'Shuangyou' and 'Beibinghong' were lower than the parental values, showing a recessionary variation, although a larger proportion (38.1%) of the progenies of 'Shuangyou' had higher total sugar content than individual parental plants. The average total acid content of the progenies of 'Zuoyouhong' was higher than the parental value, indicating the presence of additive gene effects and possible degeneration of fruit quality. In contrast, the average total acid contents of the progenies of 'Shuangyou' and 'Beibinghong' were lower than the parental values, with low-parent plant rates of 77.5% and 84.6%, respectively, indicating their potential for selecting individuals with low acid content.