Genetic Analysis And Selection Of Hybrid Offspring In Eucommia Ulmoides Oliv. Based Morphological Traits

Being an exclusive species to China, Eucommia ulmoides Oliv. was not only used as a valuable Chinese medicinal material and the industrial raw material for natural rubber, but as the good timber species and greening and the ones for water-soil conservation as well. With the understanding to its utilization value, more and more specialists at home and abroad have being focusing on the Eucommia ulmoides Oliv. genetic breeding and improvement. As a conventional means of breeding, mating has been playing an important role in forest genetic breeding because it can make the new genetic type. A factorial cross with ten parents of Eucommia ulmoides Oliv. was conducted. Morphological traits in the first and second year were measured and genetic parameters were estimated, which was the base to select the excellent families and individual and supply the reference for Eucommia ulmoides Oliv. genetic breeding and improvement. The main results are as follows:1. The results revealed that hybrid offspring had significant difference among and within families in eight traits in the first year. Male parent Qin Zhongl had the highest general combining ability than other height and ground line diameter. Female parent DaYe had the highest general combining ability than other leaf area, length of leaf and width of leaf. Family11, DaGuo×QinZhongl, had the highest specific combining ability in height of seedling. Family2, Xiao Ye X QinZhong2, had the highest specific combining ability in ground line diameter. And family16, YanCi×QinZhongl, had the highest one in leaf area and length of leaf.2. The results showed that selection can be carried among and within families by contrasting of the nine traits in the second year. Female parent Xiao Ye has the higher general combining ability than others so it can be used in the breeding programmer. And the specific combining ability was significant difference among nine traits of the cross. Family21, HuaZhong2×QinZhongl, had the highest specific combining ability in height and ground line diameter. And family1, Xiao Ye×QinZhongl, had the highert one in leaf area and length and mass of leaf.3. There was significant positively correlation between the first year and the second year in height, width of leaf and petiole length. Based on comprehensive analysis of three traits including height, ground line diameter and leaf area in the second year,5superior families were selected. The gains in height, ground line diameter and leaf area would be13.93%,8.73%and6.18%, respectively, compared with the mean of overall hybrid families.80superior individuals with mean height172cm and mean ground line diameter15.51mm had be selected in the second year. The gains in height and diameter were56.57%and48.75%respectively.