Morphoanatomical aspects of the starting material for the improvement of pineapple cryopreservation by the droplet-vitrification technique.

Patrícia A Guerra,Carlos A S Ledo,Fernanda V D Souza,Everton H Souza,Ariel Villalobos-Olivera,Mônica L Rossi,Marcos E Martinez-Montero,Daniela A S Max

doi:10.1590/0001-3765202120190555

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.

Highlights

Advances in biotechnology have provided new options for short- and long-term multiplication and conservation of plant biodiversity, using in vitro culture techniques
The analysis of variance revealed a significant effect of genotype alone as well as the genotype x culture time interaction on the regeneration rate of the shoot tips in the control group (LN -) and the group only immersed in liquid nitrogen (LN +) (Table I)
The results obtained for the controls only exposed to PVS2 of the different genotypes were highly variable, ranging from 10% regeneration of BGA-750 tips cultured for 45 days to 100% for BGA-119 cultured for 30 days (Table II)

Summary

Introduction

Advances in biotechnology have provided new options for short- and long-term multiplication and conservation of plant biodiversity, using in vitro culture techniques. The cryopreservation of pineapple shoot tips has been accomplished with different protocols, through the techniques of encapsulation-vitrification (Gamez-Pastrana et al 2004), vitrification (González-Arnao et al 1998, 2000, Martinez-Montero et al 2005, 2012), and more recently, droplet vitrification (Souza et al 2016, 2018). Exposure to the PVS2 (plant vitrification solution) for 45 minutes promoted the best performance for the majority of genotypes, some responded better to exposure times of 30 and 60 min This variability demonstrates the need to consider the effect of genotype for successful cryopreservation of pineapple (Souza et al 2016) and can be a barrier to the repeatability of the protocol for different cultivated or wild varieties

Objectives

Methods

Results