In vitro propagation and acclimatization of genipapo accessions

Propagação in vitro e aclimatização de acessos de jenipapeiro

ABSTRACT

Genipapo is a species with an intermediate seed storage behavior, and its germination is slow and asynchronous; therefore the tissue culture is an alternative strategy for the propagation in large-scale. This study aimed to evaluate three genipapo accessions at different micropropagation stages (adventitious shoot induction, in vitro rooting and acclimatization). Genipapo nodal segments from the Sabinópolis (AS), Cruz das Almas (CZA) and Núcleo Bandeirante (NB) accessions were used and inoculated in culture media with 0 and 1.0 mg L^-1 6-benzylaminopurine (BAP). Different indole-3-butyric acid (IBA) concentrations were tested for in vitro rooting. Subsequently, the effect of two substrates on the seedling development of three genipapo accessions was assessed. The molecular characterization of accessions was performed using 15 inter-simple sequence repeat (ISSR) primers, and genotype clustering was performed based on genetic dissimilarity using the Unweighted Pair-Group Method with Arithmetic Mean (UPGMA). Culture media supplementation with 1.0 mg L^-1 BAP favors the development of adventitious shoots and promotes a higher callogenesis percentage, leaf number and feasibility at 90 days of in vitro culture. The immersion of the basal portion of shoots for 20 seconds in all IBA solutions induces the rhizogenesis in the genipapo accessions at 90 days of in vitro culture. The substrates consisting of washed sand + dried coconut shell powder, at a 1:1 ratio by volume, and Topstrato HT(r) may be recommended for genipapo acclimatization. The NB accession is genetically different from the CZA and AS populations and shows superiority for most of the variables analyzed.

Index terms:
Genipa americana; in vitro culture; micropropagation