Objective: To reveal the change regularity in contents of total polysaccharides and alkaloids and select superior families from seedlings of different F1 generations hybridized from superior parents of Dendrobii Officinalis Caulis. Method: The 26 superior parents from 4 provenances were selected to achieve 26 mating combinations. Contents of total polysaccharides and total alkaloids were determined by methods of phenol-sulphate colorimetry and acid-dye colorimetry respectively. The superior families were selected using correlation analysis and cluster analysis combined with the previous agronomic traits. Result: There were extremely significant differences in contents of polysaccharides and alkaloids among different mating combinations (P<0.01). There was significant difference in content of polysaccharides among half-sib families (P<0.05)

but no significant difference was found in content of alkaloids among different half-sib families. Meanwhile

the variations of polysaccharides and alkaloids contents in full-sib families were significantly lower than those in half-sib families. Moreover

the number of leaves in seedling stage of Dendrobii Officinalis Caulis and the polysaccharide content;length-width ratio of leaves

root-shoot ratio and the alkaloids content were positively correlated

respectively. The 26 mating combinations were divided into 5 groups. Plants from the second group grew much better than the others. Conclusion: The selection of parents should be emphasized when selecting superior families from different F1 generations. There were higher genetic gains and superior uniformity in full-sib families than those in half-sib families. Combined with the previous agronomic traits

6 superior families (66×9

68×2

91×69

66×65

69×91

66×17) were selected

presenting superior characteristics of seedlings including high and thick stem with less branch

large and long leaves

strong deep roots and high content of total polysaccharide. The work has laid foundations for the later selection.