To identify truthfulness of distant hybrids for Cunninghamia lanceolata(Chinese fir) × Platycladus orientalis,a series of exploratory experiments were conducted with 9 intersimple sequence repeat(ISSR) primers having polymorphism screened out from 100 University of British Columbia(UBC) primer Set # 9(800-900).

Furthermore, it is a great challenge to map QTL underlying threshold traits and quantitative traits as well in animal outbred population because of unknown information of marker linkage phrase and discrete nature of threshold traits which resulting in reduced variation in the phenotypic distribution.