Accepted 9th October, 2015
Small size and slow ex vitro growth rate of in vitro produced pineapples (Ananas comosus L. Merr) constitute a production and marketing problem for large-scale farmers. To accomplish that we conducted a study to elucidate the effect of various soil media on growth enhancement at the nursery stage of in vitro produced pineapple propagules after the acclimatization phase in greenhouse Consequently, we investigated the effect of various soil mixes namely medium A (sand), B (silt), C (1 sand and 1 silt), D (2 sand: 1 silt), and E (1 sand: 2 silt) on the growth of in vitro produced pineapples following acclimatization phase in greenhouse. The results revealed that the highest growth parameters in terms of leaf number, leaf length, and number of roots were associated with silt medium followed by medium D (2 sand: 1 silt) and the least values obtained from medium E (1 sand: 2 silt). Root length and leaf width were not soil type dependent. Effect of mycorrhization was only apparent in 8%of plants from the treatment B (silt) yielded signs of nodulation.Survival rate of ex-vitro pineapple propagules regardless of soil type was almost 100% and this was attributed to the maintenance of humidity by the plastic cover (microclimate).In conclusion, the efficacy of the use of plastic bags, tunnels or greenhouse for growth enhancement should be investigated, and the optimum stage at which the propagules should be transplanted must also be determined. Thus if clonal propagation is a priority to maintain uniformity of pineapple production, field tests of in vitro propagated pineapple is necessary to determine the degree of genetic stability and as well avoid off-types derived from in vitro propagation.
Keywords: Low cost growth, in vitro, Pineapples Ananas comosus L. Merr, propagules, nursery conditions