Cryopreservation of cell suspensions and embryogenic calluses of Citrus using a simplified freezing process

A simplified cryopreservation process was experimented with a cell suspension of willow leaf mandarin and embryogenic calluses of six varieties of-Citrus. Its efficiency was comparable to that of the standard freezing protocol developed-pretiously for these materials, which required the use of a programmable Freezing apparatus. The cell suspension could be frozen without modieing the original pretreatment conditions (0.15 M sucrose + 5 YO DMSO). Embryogenic calluses .of five varieties out of the six experimented withstood cryopreservation with the simplified freezing process. Optimal results were obtained by increasing the DMSO concentration to 1 O or 15 %.