Abstract:

China has a rich and diverse walnut resource. There are considerable differences in appearance quality, economic
characters and nutritional components of walnuts from different growing regions. In this study, the comprehensive characters
of walnuts from different climate areas (Huanan county of Heilongjiang, Aksu city of Xinjiang, and Linzhi county of Tibet)
were explored by projection pursuit method. An obvious difference in sensory indices of walnuts from different geographic
origins was observed. The fruit shape index of walnuts from Xinjiang was 1.54, which was significantly higher than that
of walnuts from Heilongjiang and Tibet. Similarly, walnuts from Heilongjiang had significantly higher shell thickness than
walnuts from Xinjiang and Tibet despite having lower nut weight. A significant difference in kernel rate of walnuts from
different geographic origins was observed, the kernel rates of walnuts from Xinjiang and Heilongjiang were 56.15% and
16.84%, respectively. Walnuts from Tibet and Xinjiang showed a significantly increased level of crude fat (61.45% and
59.87%, respectively) when compared with those from Heilongjiang. Walnuts from Heilongjiang exhibited the highest
protein content. Comprehensive evaluation showed that the projection value of walnuts from Xinjiang was the highest (2.0703)
and kernel rate and shell thickness were the most critical indicators for comprehensive evaluation.

Key words: walnut, comprehensive characters, projection trace, evaluation