Viability and genetic stability of pineapple germplasm after 10 years of in vitro conservation

摘要

The resumed growth of plants conserved in vitro and the maintenance of genetic stability after long periods in a slow growth regime are fundamental to the success of in vitro conservation. This study aimed to evaluate the viability of pineapple plants conserved in vitro for 10 years, by triggering resumed growth and measuring the propagative potential and genetic fidelity using ISSR markers. Conserved plants of 66 accessions were micropropagated by five subcultures with an interval of 45 days. The number of shoots was counted and the propagative potential was calculated by geometric growth of the different accessions. A box plot was constructed to express the variability of the botanical varieties during the subcultures and a Poisson log-linear model was fitted to the data from multiplication of the shoots, and the genetic stability was studied with ISSR markers. All the preserved accessions resumed growing after 10 years. The geometric growth rate indicated a reduction of the propagative potential of all the accessions evaluated. No somaclonal variation was detected in the plants of the Ananas comosus var. comosus and A. comosus var. ananassoides, but probable somaclonal variants were detected in two accessions of A. comosus var. bracteatus, when compared to the stock plant in the field. The results allow standardizing an interval of 24 months between subcultures in the accessions evaluated, facilitating management of the bank. This is the first report of the effect of in vitro conservation on the resumed growth, propagative potential and genetic stability of pineapple plants.