Abstract:

Multiple statistic methods were used to analyze relationship between agronomic traits and yield of sweetpotato in regional trails of North China. Results showed that effects of agronomic traits on fresh weight, dry weight and starch yield were different. Significant linear relationships existed between dry/fresh weight and weight of stem and leaf per plant, percentage of large and middle tuberous root, percentage of small tuberous root, and number of tuberous root per plant. The same relationship was also showed between starch yield and weight of stem and leaf per plant, percentage of dry content by regression analysis. Fresh weight of sweetpotato was extremely significant negative correlation relationship with percentage of dry matter content, percentage of starch content, and disease index by correlation analysis. Not only that, fresh weight had significant positive correlation with percentage of large and middle tuberous root, while significant negative correlation with percentage of small tuberous root. Dry weight had significant positive correlation with percentage of dry matter content, while significant negative correlation with branch number. Starch weight had significant positive correlation with percentage of dry matter content and starch content, while significant negative correlation with branch number. Influence of percentage of big and middle tuberous root and percentage of starch content on yield were higher, the magnitude and direction of weight of stem and leaf per plant, length of vine, branch number, percentage of dry matter content on fresh weight, dry weight and starch weight were different. Accordingly, plant with higher stem diameter, shorter length of vine, fewer branch number, regular tuberous root, moderate the number of tuberous root, higher percentage of big and middle tuberous root were preferred in high yield cultivation. Percentage of dry matter content and starch content were still emphasized in variety choosing of high dry matter and starch.