棉 花 学 报 Cotton Science 2006，18(6)：347-351
Application of Bark Grafting Method on Grafting of Regeneration Cotton Abstract：Bark grafting method is applied in grafting of regeneration cotton for the first time，and its manipulation processes and skills are also introduced in detail. The advantages of bark grafting lie in its simpleness，easy operation，and the high survival rate of regeneration plants. Leaf remaining and tip pruning of stocks is propitious to the well growth of cions of live regeneration plant. In the experiment，Hai 7124 ( Gossypium barbadense L.) with strong root system and highly resistance to disease was selected as stocks ， and regeneration plant of Coker 312 was used as cions.The growth stage of stocks，survival rate and growth rate of bark grafting were compared with those of cut grafting. The results indicated that the method of cut grafting had strict demand for growth stage of stocks or the proportion of diameter between stocks and cions. As to cut grafting，the growth period of 35～40 days stocks (i.e. stocks with 3～5 leaves) was the best suitable period of grafting. The survival rate of regeneration cotton at this stage was higher than heretofore or after. In addition，the same size of diameter between stocks and cions was needed for cut grafting because it could make the cambiums be integrated completely. Bark grafting had no strict selection on the growth stage of stocks or the proportion of diameter between stocks and cions when compared with the method of cut grafting. The survival rate of grafting of regeneration cotton was about 90% using 35～66 days stocks (i.e. the growth stages of stocks from four or five euphylla to florescence) in bark grafting. So under the precondition with the same highest survival rate of regeneration cotton in bark grafting，the available time of stock was prolonged one month than in cut grafting. Under the condition of the same growth stage of stock and the same grafting time，the survival rate might had significant difference between two grafting methods，whereas the growth rate of cions had no difference. It suggestd that the growth rate of cions was significantly positively correlated with stock growth stage (35～66 days) (r=0.94). Since the inosculation of cambium was tighter and stocks had the flourish roots in bark grafting ， it relatively reduced the surviving time of regeneration plants under the precondition of remaining the high survival rate of regeneration plants. Since new strategies of keeping humidity and ventilating were adopted in grafting，in which grafting and shoot hardening were performed simultaneously，regeneration plants need not be hardened before grafting and the time for seedling revive could be effectively reduced. In this report，essentials of grafting，management after grafting，and practical manipulation skills of regeneration plants were also discussed. It came to the conclusion that the selection of optimal grafting strategy lied on the growth stage of stock. The 35～40 days stocks (i.e. stocks with 3～5 leaves) were fit for cut grafting while 35～66 days stocks (i.e. the growth stages of stocks from four or five euphylla to florescence) were fit for bark grafting. In general，bark grafting was better than cut grafting as a whole.
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