PJB-2019-358
The study of effectiveness of reaumuria soongorica early selection and superior family selection
Xiao E Liu
Abstract
The excellent traits of forest tree can not expression if the selection is carried out too early, whereas the traits will tend to be consistant or maybe lead less difference if the selection is started too late in the forest tree selection. Therefore, it is one of the most important work in early stage of selection to study the selection age for excellent traits of forest tree. 100 individual seedlings of Reaumuria soongorica were studied for four years in order to probe the early selection period and effectiveness, the content of soluble sugar (SS), soluble protein (SP), free proline (Pro), total chlorophyll (Chl), Chl a, Chl b, and Chl a/b of R. soongorica leaves were measured. The above 7 physiological parameters were also determination in 84 families of five–year–old R. soongorica seedlings using subordinate function analysis and principal component analysis method to comprehensive evaluate drought resistant ability of R. soongorica and using clustering analysis methord to supply superior family for forest tree breeding. The results showed that the physiological indexes (SS content, SP content, Pro content, Chl content, Chl a content, Chl b content, and Chl a/b content) had significant differences, respectively among two–year–old, three–year–old, four–year–old and five–year–old Reaumuria soongorica seedlings, While SS content, SP content and free Pro content showed decreasing trends and the total Chl content, Chl a content, Chl b content and Chl a/b showed increasing trends from two– to four–year–old R. soongorica seedlings, but stabilized from four– to five–year–old seedlings. However, no significant difference was observed in physiological indexes between of four– and five–year–old seedlings, which indicated that each physiological trait was stably expressed when the seedling age was greater than or equal to four years old and drought–resistant selection could be carried out based on physiological indexes. Results on the 84 selected families suggested that Pro, SS, SP, total Chl, Chl a, Chl b, and Chl a/b showed considerable differences between families. Subordination function method and principal component analysis were used to select the 84 families according to a selection rate of 15%, which showed that the selection results were highly consistent and the repetition rates of the two methods both reached 92.3% indicating both methods of drought resistance selection were feasible, and 12 families were selected with high drought resistance. The clustering analysis of the 12 families with drought resistance ability was performed that 12 families were classifed into 4 classes with a clustering distance of 5, which had extremely strong, strong, relatively strong and mediun drought resistance ability, respectively.
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