A Primary Study On Selection In Field For Breeding New Oil-used Paeonia Rockii Varieties

This study focused on selecting Paeonia rockii parents to breed new oil-used cultivars, by doing investigations in the fields during the flower and fruit phase in late April and early August, 2014. 75 superior Paeonia rockii plants were selected from 3 regions, Lanzhou, Lintao and Yuzhong, of Gansu Province. Each plant was marked and their fruits were taken to the lab for further studies. In late November, 2014, our team went to the 3 places for the 3rd time and transplanted all the marked plants in Yangling, Shaanxi Province. During the field work, 17 traits related to the flowers and fruits were measured. Later in the lab traits related to the seeds and the fatty acids(FAs) contents were measured as well. By using methods such as variation calculation, simple correlation, multiple comparison and path analysis, conclusions were made showing that the selected plants of each region had higher yield than the average level. Among the 3, the selected group from Lintao topped on both yield and FAs content. This founding could offer references for the future breeding work. Main results were listed below:1. We first researched on Gansu Paeonia rockii for the oil cultivar breeding, through selection work in the field. Out of almost 10,000 Paeonia rockii plants from 3 regions of Gansu Province, 10 from Lanzhou, 45 from Lintao and 20 from Yuzhong were selected for their higher yields than the average levels. However, regarding to FAs content, there was no significant difference between the 3 groups and their controls.2.The selected Paeonia rockii plants were in plenty of colors such as white, light yellow, yellow, light pink, pink, dark pink, red, pinkish red, dark red, light purple, purple and dark purple. The colors had no correlation with the yield. The flower number determined the fruit number. Besides, the stem length, petal length were in association with the fruit number, and the outside petal width positively associated with the oil yield rate.3. The rooting rate, oil yield rate, seed plumpness and unsaturated FAs content showed no significant difference among the 3 groups of the 3 regions. The oil yield rate ranged from 20% to 25%, the average of which met the national standard of oil-used tree peonies(≥22%).4. The rates of unsaturated FAs/total FAs ranked as Lanzhou group(96.83%), Lintao group(92.97%) and Yuzhong group(92.62%), where were all higher than the average level of oil-used peonies(83.42%).5. Lintao group had great yield advantage over the other 2 groups. The number even topped the total number of Yuzhong group and Lanzhou group. Specifically the fruit weight, seed number of a single fruit, hundred seeds weight and seed diameter of Lintao group all showed higher values than the other 2 groups. Additionally the yield-related variation coefficients of Lintao group were relatively low, meaning the individuals in this group had better stability with regards to yield property.