Fifteen cuttings of each donor were taken from a clonal hedging orchard and rooted in Hunan Province in spring of 1991. A total of 552 clones were selected out of 1 000 clones based on rooting percentage, growth rate ...Fifteen cuttings of each donor were taken from a clonal hedging orchard and rooted in Hunan Province in spring of 1991. A total of 552 clones were selected out of 1 000 clones based on rooting percentage, growth rate and resistance to disease and insects in 1992 and was divided into two groups. One group contained 252 clones and was planted in Hubei Province in a randomized complete block design with single tree plot and 5 replications. Seedlings from a local source were used as controls. About 15% of the least desired clones were rogued from the test plantations and the clonal hedging orchard in 1994 and 1997 It was found that: the height, diameter and volume growth of the stecklings were consistently and significantly higher than those of the seedlings over the years; the absolute growth difference between the seedlings and the stecklings increased with age dramatically, however, the gain as a percentage of current size decreased rapidly; there were significant differences among clones and roguing raised the average performance of the steckling population; early late correlation coefficients in growth of the clones were low. The results indicated that clonal selection can be done in combination with timber production and the increase of plantation performance and the development of clonal varieties can be achieved incrementally over time by roguing in the cutting orchard. The method was likely to be more effective for Chinese Fir than traditional clonal breeding method. The high percentage of gain from early selection will be low at rotation age and few clones that have not been well studied should not be used in production practice.展开更多
文摘Fifteen cuttings of each donor were taken from a clonal hedging orchard and rooted in Hunan Province in spring of 1991. A total of 552 clones were selected out of 1 000 clones based on rooting percentage, growth rate and resistance to disease and insects in 1992 and was divided into two groups. One group contained 252 clones and was planted in Hubei Province in a randomized complete block design with single tree plot and 5 replications. Seedlings from a local source were used as controls. About 15% of the least desired clones were rogued from the test plantations and the clonal hedging orchard in 1994 and 1997 It was found that: the height, diameter and volume growth of the stecklings were consistently and significantly higher than those of the seedlings over the years; the absolute growth difference between the seedlings and the stecklings increased with age dramatically, however, the gain as a percentage of current size decreased rapidly; there were significant differences among clones and roguing raised the average performance of the steckling population; early late correlation coefficients in growth of the clones were low. The results indicated that clonal selection can be done in combination with timber production and the increase of plantation performance and the development of clonal varieties can be achieved incrementally over time by roguing in the cutting orchard. The method was likely to be more effective for Chinese Fir than traditional clonal breeding method. The high percentage of gain from early selection will be low at rotation age and few clones that have not been well studied should not be used in production practice.
