21 CryoLetters 23, 21-26 (2002)  CryoLetters, c/o Royal Veterinary College, London NW1 0TU, UK FIELD PERFORMANCE OF SUGARCANE ( Saccharum sp.) PLANTS DERIVED FROM CRYOPRESERVED CALLUSES M.E. Martínez-Montero 1* , E. Ojeda 2 , A. Espinosa 2 , M. Sánchez 1 , R. Castillo 1 , M.T. González-Arnao 3 , F. Engelmann 4, 5 and J.C. Lorenzo 1 1. Centro de Bioplantas, Universidad de Ciego de Avila, CP 69450, Ciego de Avila, Cuba. 2. Estación Provincial de Investigaciones de la Caña de Azúcar, Ciego de Avila, Cuba. 3. Universidad de La Habana, Fac. Biología, Calle 25 e/ J e I, Vedado, La Habana, Cuba. 4. International Plant Genetic Resources Institute (IPGRI), Via dei Tre Denari 472/a, 00057 Maccarese (Fiumicino), Rome, Italy. 5. Institut de recherche pour le développement (IRD), 911 avenue Agropolis, 34032 Montpellier cedex 01, France (current address). * correspondence (email: marcosem@bioplantas.cu; cubaplantas@gmail.com) Abstract This study compared the field performance of sugarcane plants originating from three different sources: control, non-cryopreserved embryogenic calluses, cryopreserved embryogenic calluses and macropropagated material of the same commercial hybrid. Several agronomic traits were evaluated on 100 plants per treatment over a 27-month period covering the growth of the stool and of the first ratoon. Significant differences between treatments were observed only during the first six months of field growth of sugarcane stools. Stems produced from in vitro cultured material, irrespective of their cryopreservation status, had a smaller diameter and a shorter height than those produced from macropropagated material. These differences disappeared by12 months of stool field growth. Keywords: sugarcane; Saccharum sp.; cryopreservation; embryogenic callus; macropropagated material; field performance. INTRODUCTION The sugarcane industry is among the most important businesses in Cuba. This industry is in dramatic need of planting material, which cannot be produced in sufficient quantities to meet the demand using classical macropropagation techniques. Biotechnological tools have been employed to increase the production of planting material. Castillo (1) has developed a protocol for sugarcane somatic embryogenesis, which allows mass production of plants from elite varieties. However, despite its success, this protocol has an important limiting factor, which lies with the progressive loss over time of the embryogenic potential of calluses. A simplified freezing protocol has thus been established for sugarcane embryogenic calluses which allows their conservation for the long-term with their embryogenic potential intact (15). It was successfully applied to three commercial hybrids ( Saccharum sp. cv. CP52-43, C91- 301 and C1051-73). The survival percentages of cryopreserved calluses ranged between 20 and 94% depending on the variety, and fully developed plantlets could be obtained from regenerating calluses. Embryogenic calluses of variety CP52-43 were stored for 14 months in liquid nitrogen without any effect on survival and plantlet production. Before using cryopreservation as an additional tool in the overall conservation strategy for any plant material, it is essential to verify that the cryopreservation protocol developed does not have any destabilizing effect and that the plants produced from cryopreserved explants are true to type. There exist an increasing number of reports indicating that no