Study on Filial Generation of Single Parent in Second-generation Seed Orchards of Chinese Fir

The height and DBH of 5 to 7-year trees of filial generation of single parent were tested and analysed in 1997-1999 in second generation seed orchard of Chinese fir(Cunninghamia lanceolata(Lamb.)Hook) in Changle Forestry Center.The results showed that the growth traits of height and DBH were most significantly different among the tested families.The heritabilities of height and DBH of families different years in were 67.02%、73.41%、54.95%、59.18%、55.48% and 47.37% respectively.The genetic gain of families of plus tree of superior provenance and hybrid match was more than that of the families of plus tree of superior families of first generation seed orchard of Chinese fir.The genetic gain of second generation seed orchard was more than that of the filial generation of superior provenance and mixed families filial generation of first generation and 1 and(1.5) generation seed orchard.The selection was effective on material of second generation of Chinese Fir and the second generation seed orchard rebuilding was successful.