Plus tree selection of Cornus walteri.

In this paper, Cornus walteri resources in Shandong Province were used as the research object, 45 candidate plus trees were selected initially based on the extensive survey data. The oil yield of C. walteri was selected as breeding objective. According to the biological characteristics of C. walteri, the relatively stable traits less influenced by age were used as selecting traits for plus trees, including nine traits, such as fruit number per infructescence, fruiting-branch ratio, 100-dry-fruit weight, oil content of fruit, 100-seed weight, crown height ratio, crown index, consistency of fruit ripening, and pest and disease resistance. The mean, standard deviation and range of the traits were used to establish comprehensive scoring method of plus trees, and 21 plus trees were selected from the candidate plus trees according to the method. The comprehensive scoring method for plus tree selecting provides a scientific method and achieves preferable selecting effect for plus trees.