Abstract: Direct transplant of cotton somatic regenerated plants, transgenic plants and other types of axenic plantlets are rather difficult, normally with lower survival ratios. To some extent, low survival ratios limit the application of biotechnology and cyto-engineering in cotton genetic improvement. Cotton graft can solve this problem preferably, and be well employed in conservation of the rare germplasm materials, genetic segregative populations and incompatible interspecific hybridization. In the study, a new high–efficient graft technique in cotton was explored and designated as cotton join graft technique. Cotton transgenic plants, F2 segregative population and general plants were grafted by using this technique. The results showed that the survival ratios ranged from 90% to 100%, and obviously were genotype independent. It was better that the rootstocks were with more 1-2 leaves than scions when grafting. The survival ratio was the highest when the scions were in 1 leaf and rootstock seedlings in 2 leaves. The scions should be remained at least 1 leaf. Higher survival ratios were obtained when the scion and rootstock from the same cotton variety compared those from different cottons. And the hybrids as rootstocks could get better effects.

Key words: Cotton, New graft technique, Transgenic plants, Genetic segregative population