Number of explants, culture medium and photoperiod in ornamental pineapple micropropagation

Abstract

One of the factors limiting the expansion of commercial cultivation of the ornamental pineapple, Ananas comosus var. erectifolius (LB Smith) Coppens & Leal, is the availability of plantlets in quantity and of quality. Micropropagation makes it possible to obtain higher rates of multiplication, and ensures the high quality of the resultant plantlets; however the cost of producing this kind of propagating material is still relatively high. This study therefore aimed to determine a more appropriate relationship between the number of explants per flask, culture medium and photoperiod, with a view to increasing the in-vitro rate of multiplication of this variety of ornamental pineapple, and consequently optimise production costs of the micropropagated plantlets. A completely randomised design was used, with treatments involving three factors: number of explants per flask (4, 5 and 6), culture medium (MS + 0.54 μM NAA plus 2.22 μM or 4.44 μM BAP) and photoperiod (12 and 16 hours), with ten replications. At the rates of multiplication obtained, there were significant differences for photoperiod and interaction of the three factors under analysis. No significant differences were noted for the number of explants per flask, or for the culture medium taken alone. From an economic standpoint, the use of six explants per bottle is recommended, grown on a medium of MS + 4.44 μM BAP + 0.54 μM NAA, under a photoperiod of 12 hours.