Assessment of the Applicability of Morphometric, Organoleptic and Phylogenetic Analyses to Differentiate Soft and Firm Flesh Bearing Trees of Jackfruit (Artocarpus heterophyllus Lam.) in Sri Lanka

Abstract

Purpose : The aril/flesh of the fruitlets is the main edible part of jackfruit (Artocarpus heterophyllus Lam.). There are two flesh types; soft flesh (SF) (Wela) and firm flesh (FF) (Waraka) (i.e. highly preferred). There is no strategy available to identify FF plants at nursery or vegetative stages. Thus the present study was conducted to assess the applicability of leaf morphological variation and DNA bar-coding to differentiate SF and FF bearing jackfruit plants. Research Method : The syncarp morphology and sensory parameters of SF and FF ripen flesh were also assessed to check the variation with 10 trees from each flesh type. The trees were chosen from SF and FF types and leaves and mature syncarps were collected. The leaf and syncarp morphological variation, pH, soluble solids and ascorbic acid content were measured. The sensory parameters of the flesh types were ranked by employing a taste panel. The DNA bar-coding was carried out for two loci rbcL and ITS to identify the sequence variants.Findings : The leaf tip length was longer in SF, ascorbic acid content was higher in FF and all the other parameters were not different (P < 0.05). The SF leaves were elliptical whereas FF leaves were obovate. The association analysis revealed that the sweetness and sourness of flesh were inversely associated. The DNA bar-coding for rbcL and ITS showed that rbcL locus was not informative however, ITS locus can be used to characterize the genetic diversity of jackfruit.Research Limitations : The detected haplotypic variants must be further validated with a larger set of jackfruit trees collected from diverse sites.Originality/value : Three haplotypes were detected within ITS locus where CC haplotype is characteristic to SF and CT or TC is detected in FF enabling marker assisted seedling selection. This is the first reported study attempting to use sequence variants to differentiate SF and FF typed trees in jackfruit.