Assessment of the elite accessions of bael [Aegle marmelos (L.) Corr.] in Sri Lanka based on morphometric, organoleptic, and elemental properties of the fruits and phylogenetic relationships.

Aegle marmelos L. (Bael) is a native tree fruit species in the Indian subcontinent and Southeast Asia. Bael is a popular fruit because of its significant nutritional and medicinal properties. However, bael is an underutilized fruit species in Sri Lanka. Thus, Fruit Crop Research and Development Station of the Department of Agriculture of Sri Lanka has selected five elite bael accessions (Beheth Beli, Paragammana, Mawanella, Rambukkana, and Polonnaruwa-Supun). We assessed these five accessions for the variation of the fruit size, pulp, organoleptic preference, elemental properties, genetic diversity, and evolutionary history. The fruits at the golden-ripe stage were collected during the peak fruiting seasons in 2015, 2016, and 2017. The fruit size, pulp, shell thickness, and seed size were measured and subjected to the General Linear Model (GLM) and Principal Component (PC) Analyses. The fruit pulp was distributed among a group of 30 taste-panelists to rank for the parameters: external appearance, flesh color, aroma, texture, sweetness, and overall preference. The rank data were subjected to association and PC analyses. The elemental contents of the fruit pulp samples were measured using Inductively coupled plasma mass spectrometry and subjected to GLM and PC analyses. We observed a significant diversity in fruit size, organoleptic preference, and elemental contents among bael accessions. Rambukkana and Polonnaruwa-Supun yield the biggest and most preferred fruits. We used trnH-psbA, atpB-rbcL spacer, matk-trnT spacer, and trnL markers to construct phylogenies. Sri Lankan bael split from an Indian counterpart, approximately 8.52 MYA in the Pliocene epoch. However, broader germplasm of Indian bael must be assessed to see the presence of any independent evolution within Sri Lanka.

Characterization of the FMDV-serotype-O isolates collected during 1962 and 1997 discloses new topotypes, CEY-1 and WCSA-1, and six new lineages.

The genetic diversity of the FMD viruses collected from the outbreaks during the second half of the 20th Century in Sri Lanka was assessed in the present study. We sequenced the VP1 genomic region of the samples collected during FMDV epidemics caused by serotype O in Sri Lanka during 1962 and 1997. For comparison, we sequenced the VP1 of the related viral isolates collected from other Asian countries. We analyzed the VP1 sequences of the viral strains using the UPGMA method with uncorrected pairwise distances. Nucleotide divergence (ND) thresholds of 15%-20% and 5%-<15% were used to differentiate topotypes and lineages, respectively. We calibrated the divergence times and lineage-specific substitution rates using Bayesian-skyline models. Based on the ND estimations and phylogenetic relationships, we identified and named two new topotypes [CEYLON 1 (CEY-1) and WEST, CENTRAL AND SOUTH ASIA 1 (WCSA-1)] and six new lineages (Syr-62, Srl-77, Tur-69, May-78, Tai-87 and Bur-77) of serotype O. We believe that the novel topotypes and lineages named may have disappeared although they have similar substitution rates for epizootic outbreaks. Because the amino acid selection analysis revealed that the two topotypes and six lineages identified were under purifying selection during the outbreaks.