College of Life Science Zhejiang University Hangzhou 310029 China;
Department of Bio-Chemistry Liuzhou Teachers College Liuzhou 545003 China;
Key State Laboratory of Systematic and Evolutionary Botany Institute of Botany the Chinese Academy of Sciences Beijing 100093 China;
FISH; interspecific hybrid; meiotic behavior; rDNA; Pinus strobus; Pinus wallichiana.;