Tissue Culture and Rapid Propagation System of Roselle(Hibiscus sabdariffa L.)

[Objectives]This study was conducted to establish a tissue culture and rapid propagation system of roselle(Hibiscus sabdariffa L.)[Methods]A tissue culture and rapid propagation experiment was carried out with roselle plants as materials to study the suitable explants,the best disinfection method,the best growth medium,the best rooting medium and the transplanting and domestication method of roselle.[Results]The lateral buds of roselle were the best explants.Sterilizing with 0.1%mercuric chloride for 7 min showed a contamination rate of 5%and achieved a survival rate of 90%.With MS as the basic medium,adding 1.0 mg/L 6-BA and 0.5 mg/L IBA could obtain the best effect of bud induction.The medium with the highest proliferation rate was MS+6-BA 0.5 mg/L+BA 0.1 mg/L.On the basis of 1/2MS,adding 0.5 mg/L NAA+0.5 mg/L IBA could make adventitious buds root fastest and most,and greatly improve the propagation coefficient.And 1∶1 perlite rock:peat soil was the best transplanting substrate,with which the transplanting survival rate reached 95%.[Conclusions]This study provides technical reference for rapid cultivation and large-scale planting of roselle.

Comparative Effect of Foliar Application of Cow Dung, Wood Ash and Benlate on the Disease Initiation and Development of Roselle (Hibiscus sabdariffa L.) Leaf Spot Disease Caused by Coniella musaiensis Var. Hibisci. in Makurdi, Central Nigeria

A study on the comparative effect of cow dung, wood ash and benlate for the control of leaf spot disease of Roselle (Hibiscus sabdariffa L.) was carried out following the preparation and foliar application of the materials on selected Roselle plants of the green and red accessions (Acc1 & Acc3) in the field. The cow dung was fermented for 14 days while sour milk was added to wood ash, dissolved and all filtered and labeled. The spraying commenced soon after the plants were thinned to one and was done weekly until after 50% of the plants had flowered. Results showed significant (p = 0.05) difference between benlate, the synthetic fungicide and the bio-fertilizers (cow dung and wood ash) for the two years of the study. Disease severity was significantly lower in the benlate than in the bio-fertilizers. There was no significant difference in yield between the treatments although higher yield was recorded in benlate. Though the bio-fertilizers could not suppress infection, they aided the growth of the plants by boosting luxuriant growth. The result showed that these bio-fertilizers cannot be used as substitute to the synthetic fungicide for the control of this leaf spot disease caused by Coniella musaiensis var. hibisci. However, since they give equally good yield the bio-fertilizers can still be used to minimize the reliance upon use of chemical fungicides.

Effect of Roselle calyces extract on the chemical and sensory properties of functional cupcakes

Roselle calyces(RC)are a major crop for export and used to make a common drink in Egypt.Dried RC are commercially available and appreciated to obtain concentrated extracts which might be used in the food and pharmaceutical industries for color and heath benefits.The objective of this research was to determine the chemical and the sensory properties of cupcakes formulated with Roselle calyces extract(RCE).Proximate analysis,anthocyanins,ascorbic acid,titrable acidity,%retaining of anthocyanins,color and sensory evaluations were done.RC cupcakes had high sensory scores(P<0.05)compared to control cupcakes.The parameter a*was significantly red in the RC cupcakes compared to control cupcakes along with 77%retaining of anthocyanins.The consumption of 100 g of the RC cupcakes would provide 465 mg/100 g dry matter anthocyanin that is more than 2 folds of the minimum average of the daily intake of anthocyanins for Americans,along∼1/3 of the daily dietary fiber intake to achieve fiber adequacy according to the Scientific Advisory Committee on Nutrition.RC cupcake can be a functional food and would have a“clean”label with cost effective advantage.