Dynamic Changes of Photosynthetic Characteristics in Xiaoyan 54,Jing 411 and the Stable Selected Superior Strains of Their Hybrid Progenies Genetic Diversity Analysis in Natural Hybrid Progeny of Ornamental Crabapple,Malus‘Royalty’ Genetic Diversity Analysis in Natural Hybrid Progeny of Ornamental Crabapple,Malus‘Royalty’ Growth and Photosynthetic Characteristics of the Seedlings of Sinocalycanthus chinensis Hybrid Progeny Correlation between Molecular Genetic Distances among Parents and Growth Traits of Progenies in Populus Natural Hybrids between Ligularia vellerea and L.subspicata (Asteraceae: Senecioneae)