Green-Spinach, Red-Spinach, and Tree-Spinach (‘Three-Fold Spinach’ in Sri Lanka): An Insight into Phylogenetics and Consumer Preference

Three types of spinach, green spinach (GS), red spinach (RS), and tree spinach (TS) are consumed in Sri Lanka. GS, RS, and TS are referred to as Basella alba, Basella rubra, and Talinum fruticosum respectively. However, some taxonomists categorize GS and RS under B. alba causing an ambiguity. Due to the poor sanitation, consumers prefer to purchase greenhouse-grown spinach over field grown material. However, the taste parameters of field grown and greenhouse-grown spinach have not been assessed. The objectives of the present study were to resolve the taxonomic ambiguity between GS and RS, identify the evolutionary relationship of TS to other two species and to assess the organoleptic preference on the dishes prepared using greenhouse and field-grown shoot-tops of three spinach. The genomic DNA extracted from GS, RS, and TS, PCR amplified and sequenced for the barcoding markers rbcL, ITS, matK-trnT and atpB-rbcL. The sequences obtained along with other reported related sequences were subjected to phylogenetic analysis. A sensory test was carried out using the shoot-tops of three species grown under greenhouse and field conditions. The taste panelists were asked to rank the dishes for preferred levels of color, aroma, texture, bitterness, and overall taste and the data were subjected to the association analysis. The rbcL and ITS markers separate GS and RS into two well -supported clades, B. alba and B. rubra respectively. The polymorphisms of atpB-rbcL and matK-trnT markers support the definition of two species. The monophyly of B. alba and B. rubra with T. fruticosum must be the reason for the same palate in dishes and designation of all three species under “spinach” in Sri Lanka. The taste panel data demonstrated that there is no specific fondness for greenhouse or field grown materials enabling the popularization of greenhouse-grown spinach to answer the safety concerns.