Combined effect of cytokinins on the in vitro propagation of three strawberry cultivars

Efeito combinado de citocininas na propagação in vitro de três cultivares de morango

ABSTRACT

In the in vitro propagation of strawberry plants, techniques have been applied to obtain disease-free plants with high multiplication rates. To improve the efficacy of micropropagation protocols, it is necessary to determine the effect of growth regulators, mainly cytokinins; however, there is no information regarding the combined use of trans zeatin (Zt) and other cytokinins for shoot induction. The objective of this work was to evaluate the effect of Zt combined with 6-benzylaminopurine (BAP), 6-furfurylaminopurine (KIN) or 2-isopentenyladenine (2iP) on the in vitro propagation of three strawberry cultivars. Combinations of cytokinins, Zt and BAP, Zt and KIN, and Zt and 2iP were proposed to evaluate shoot induction. For the acclimatization of the seedlings, two types of substrates were used (Pro-Mix, Pro-Mix plus humus 2:1). The use of Zt and KIN increased the average number of shoots per explant, and the greatest number of leaves and roots was obtained when Zt and 2iP or Zt and BAP were used. The Pro-Mix and Pro-Mix plus humus substrates did not significantly affect the number of leaves or roots, or the SPAD. These results indicate that the use of the combination of Zt and KIN allowed us to obtain the greatest number of shoots per explant that did not produce calli and promoted the development of the root system; likewise, the Pro-Mix or Pro-Mix plus humus substrate were adequate for acclimatization, allowing the growth and development of strawberry plants.

Keywords:
Fragaria ; Plant growth regulator; Micropropagation; SPAD index