Abstract Cryopreservation of pineapple shoot tips has been established from various protocols, including droplet vitrification. Thus, this work aimed to evaluate the morphoanatomical conditions of the starting material over different times (30, 45 and 60 days) of culture before freezing and its correlation with the survival percentage of the cryopreserved shoot tips. Four accessions, Ananas comosus var. comosus (BGA-009); var. bracteatus (BGA-119); var. parguazensis (BGA-376), var. erectifolius (BGA-750) from the Pineapple Active Germplasm Bank (BGA Pineapple) and two hybrids from the Embrapa Genetic Breeding Program, FIB-ROX1 (var. bracteatus X var. erectifolius) and FIB-ROX2 ( var. erectifolius X var. bracteatus), recently introduced in the field from in vitro storage, were used. Histological sections before freezing and the percentages of survival after freezing were obtained taking into account the different times of cultivation of the donor plants. The results showed a significative interaction between genotypes (accessions and hybrids) and the culture period. The accessions BGA-009 and BGA-119 showed the highest survival rates, with 95% and 90% respectively for the 30-day culture time. Different results were obtained for each genotype, showing the need for improvements in the standardization of starting material, which would allow better repeatability of the protocol.

In pineapple have been used cryopreservation protocols based on a vitrification procedure. However, the influence of some technical factors is still unknown to achieve a strategy cryogenic routine application to a wide range of genotypes. Furthermore, there has been no histological analysis to display any structural changes during a process of cryopreservation. In the present investigation different technical aspects of a cryogenic strategy are determined to increase survival levels from the apexes to immersion in liquid nitrogen. These were: type of apex, consisting of 3-4 leaf primordia with an approximate size of 2,5-3mm; preculture 0,3 mol L-1 sucrose; application of the loading solution 0,4 mol L-1+2 0,4 mol L-1 mol glycerol; application temperature of the vitrification solution PVS2 at 0 °C for 420 min. The analysis of the display of structural changes in the cryopreserved apices revealed that the meristematic cells in the apical dome and leaf primordia in formation, suffered few cellular alterations and kept almost intact its morpho-physiological characteristics in the best conditions of survival. The method of vitrification was applied successfully for 9 accessions of the in vitro genebank of Bioplant center. This is an important step for the establishment of a gene bank for long-term cultivation of pineapple

En la piña se han utilizado protocolos de crioconservación basados en un procedimiento de vitrificación. Sin embargo, se desconoce aún la influencia de algunos factores técnicos para lograr una estrategia criogénica con una aplicación de rutina a un amplio número de genotipos. Además hasta la fecha, no se han realizado ningún análisis histológico para visualizar cambios estructurales durante un procedimiento de crioconservación. En la presente investigación se determinaron diferentes aspectos técnicos de una estrategia criogénica para aumentar los niveles de supervivencia de los ápices a la inmersión en nitrógeno líquido. Estos fueron: tipo de ápice, compuesto por 3-4 primordios foliares con un tamaño aproximado de 2,5-3mm; precultivo en 0,3 mol L-1 de sacarosa; aplicación de la solución de carga 0,4 mol L-1+2 0,4 mol L-1 glicerol; temperatura de aplicación de la solución vitrificadora PVS2 a 0 °C durante 420 min. El análisis de la visualización de los cambios estructurales ocurridos en los ápices crioconservados reveló que las células meristemática presentes en el domo apical y los primordios foliares en formación, sufrieron pocas alteraciones celulares y mantuvieron casi intacta sus características morfo-fisiológica en las mejores condiciones de supervivencia. Se aplicó de manera exitosa un procedimiento de vitrificación para nueve accesiones del banco de germoplasma in vitro del centro de Bioplantas. Lo anterior constituye una importante etapa para el establecimiento de un banco de germoplasma a larga plazo del cultivo de la piña