English

Abstract

Artificial seed production is now an outstanding technique for plant propagation and preservation, and has been applied on many plants. This study examines, for the first time the re growth of strawberry capsules under greenhouse conditions. Maximum shoot multiplication response (61.60 shoots) was obtained in Murashige and Skoog (MS) medium having 1.0 mg l-1 of Benzyl Adenine (BA), with an average leaf number of (143.2). However, the highest average shoot length was 6.20 and recorded at 1.5 mg l-1 KN. To protect shoot tips and produce synthetic seeds, gel capsules were standardized using a combination of sodium alginate and calcium nitrate or calcium chloride concentrations. Gel capsules were most effective for the formation of uniform and firm capsules when formed with a combination of 3% (w/v) sodium alginate and 100 mM calcium nitrate for 30 min. The highest percentage of shoot emergence was recorded when encapsulated in 3% Na-alginate dissolved in MS- salt solution containing 0.5mg mg l-1 BA and stored on MS basal medium containing 0.25 mg l-1 BA. The results demonstrated that the sugarcane bagasse could be used effectively as a substitute for agar during capsules storage. The capsules grown on MS media and sugarcane bagasse increase in shoot number, leaf number and shoot length, compared with agar-grown. In vitro storage of capsules was also evaluated by adding sugar alcohols, sorbitol or mannitol, to act as osmotic agents, to the media. Using 0.1M sorbitol or mannitol each to the storage media at 4°C after 12 months increased regrowth when inoculated on growth medium. Root induction was readily achieved within six weeks when shoots were transferred to MS medium supplemented with 0.5 mg l-1 IBA. Significant improvement in the in vitro rooting process, coupled with cost reduction, were obtained by the use of sugarcane bagasse as a substitute for the traditionally used agar-gel medium and Knop medium. Further, rooted plantlets were hardened by placing them in peatmoss + perlite (1:1, v/v) achieving a 75% survival rate in this potting mixture. Finally, the encapsulated shoot-tips coated in 3% Na-alginate, 0.2 or 0.3 g l-1 topsin and 0.5mg l-1 IBA were successfully established in the greenhouse.