Analysis Of Agronomy And Quality Traits Of Advanced Diploid Potato Clones

With the rapid development of potato industry in China, and the need for processing varieties and special used varieties was more and more urgent, however, at present the genetic basis of our cultivated varieties was narrow and inbreeding is obvious, which limit the breeding effort for development of new varieties to large extent. The rich germplasm resource exists in the diploid potato, and genetic background of diploid potato is relatively simple compared with the cultivated potato. Therefore, further study in the diploid potato has much great significance for solving the narrow genetic basis or unacceptable quality traits. These experiments were grown in two years in Harbin, laid out in a random complete block design, and the main purposes are to determine whether the advanced diploid potato clones selected from crosses introduced from Canada contain rich genetic variation in agronomic traits and processing traits; then to screen out diploid potatoes with traits of interest from these diploid potatoes. This may offer new germplasm for potato breeding in future. The main results are as follows.1. Highly significant difference existed among the advanced diploid potato clones for plant height, stem number, tuber number per hill, tuber yield per hill, dry matter content, reducing sugar content, chip color, crude protein content, P content and K content, indicating that rich genetic variation exists in these diploid potatoes.2. The tuber yield per hill had a highly significantly positive correlation to plant height, main stem number and tuber number per hill, and had a highly significantly negative correlation to dry matter content. Positive highly significant partial correlation was found between yield per hill and plant height. Dry matter content had a highly significant negative correlation to P content and K content in tuber. Reducing sugar content had a highly significant negative correlation and partial correlation to chip color. Crude protein content had a significant positive correlation and partial correlation to chip color and P content, and had a significant positive correlation to K content.3. The results of path analysis indicated that plant height, stem number, crude protein content and K content had strong positive direct effect on tuber yield per hill, and that dry matter content, reducing sugar content, chip color and P content had strong negative direct effect on tuber yield per hill. Coefficient of determination in the path analysis was0.8110.4. Broad-sense heritability of plant height, dry matter content, reducing sugar content, P content and K content was more than0.8. Broad-sense heritability of crude protein content was 0.7084. Broad-sense heritability of tuber number per hill and tuber yield per hill was more than0.6. And broad-sense heritability of stem number and chip color was more than0.5.5. Cluster analysis showed that group â…  had the diploid potatoes with low reducing sugar content, light chip color and so on, so this group could be used for selecting processing stock; Group â…¡ had higher productivity, so this group could be used for selecting potatoes with higher yield. Group â…¢ had higher dry matter content, and this group could be used for selecting potato with higher dry matter content. And Group IV had low yield but high P and K content, so this group could be used for selecting potatoes with high P content and K content.6. The advanced dipoid potato clone34059was selected out as a promising dipoid stock suitable for processing into chips when compared with Atlantic, and34057and34118promising stock as table stocks as compared with Kexin13. Moreover, clones with one trait promising, for example high dry matter content, light chip color and high nutrition value, were also selected out, which may be used as parents for further breeding.In summary, based on the performance of plant traits, tuber traits, yield traits and quality traits, these diploid potatos had rich genetic variation. Estimates of broad-sense heritability further showed that selection would be effective in these diploid potatoes for high yielding, high quality and other specific traits.