Abstract:

The biological features of flowering were studied in 26 superio rindividual male Ginkgo biloba trees selected from 5050 male trees in Taian and Tancheng of Shandong Province. These superior male trees possess the features of florescence long, a large number of pollens, and high vitality of pollens, etc.The results of analysis of correlation and variance showthat the florescence prolong swith raising elevation, but numbers of microstrobil per short shoot (sh.sh.) decrease evidently.The maximum number of short shoots per meter of long shoot (l.sh.) is 45.There is a significant positive correlation between the length of short shoot and the microstrobil numbers per short shoot.The flowering percentage of short shoot of 3-year-old segment is the highest, amounting to 96 %.The maximum microstrobil per sho rt shoot is 6.45, the maximum anther per microstrobil is 58, the maximum pollen grain per anther is 23000.There are 650000 pollen grains in per microstrobil averagely.the pollen productivity of No.14 tree is 6.83 %.A 45-year-old male tree can yield 165g pollen.The mean vitality of pollen reaches 92 %.Seed production percentage is 90 %after pollination, the percentage of embryo in seeds is more than 91 %.

Key words: Ginkgo biloba, Male tree, Pollen, Vitality, Biological feature