The establishment of the species-delimits and varietal-identities of the cultivated germplasm of Luffa acutangula and Luffa aegyptiaca in Sri Lanka using morphometric, organoleptic and phylogenetic approaches

Abstract

Luffa acutangula and L. aegyptiaca are two vegetable species commonly found in South and South East Asia. L. acutangula is widely grown; however, L. aegyptiaca is considered as an underutilized crop. The species delimits, phylogenetic positions, and the varietal identities of L. acutangula and L. aegyptiaca in Sri Lanka are not known. Thus, in the present study, we aimed to establish the species delimits and varietal identities of L. acutangula and L. aegyptiaca varieties grown in Sri Lanka using morphometric, phylogenetic and organoleptic assessments. We assessed five varieties of L. acutangula and three varieties of L. aegyptiaca. The vegetative and reproductive data were collected for the morphometric analysis and DNA sequence polymorphism of the makers rbcL, trnH-psbA and ITS for the phylogenetic analysis. We also conducted an organoleptic assessment based on taste parameters; aroma, bitterness, color, texture, and overall preference using the dishes prepared according to the most common Sri Lankan recipe for Luffa. The variation of the vegetative and reproductive traits grouped L. acutangula varieties into two distinct clusters. The trnH-psbA polymorphism provided the basis for the species delimits of L. acutangula and L. aegyptiaca. The rbcL and ITS polymorphisms provided the basis for the identities of the varieties of L. aegyptiaca and L. acutangula respectively. In the phylogeny, the L. acutangula varieties of Sri Lanka formed a unique clade and the L. aegyptiaca varieties formed a reciprocal monophyletic group in comparison to worldwide L. aegyptiaca reported. The taste parameters aroma, texture, color, and overall preference were significantly different among the Luffa varieties. The L. aegyptiaca varieties received lower preference in the organoleptic assessment. The present study sets the species delimits, phylogenetic positions and the varietal identities of the cultivated germplasm of Luffa and revealed the distinct morphological and organoleptic properties of each variety.