Evaluation of the agronomical traits and saponin content of wild bitter gourd accessions (Momordica charantia L. var. abbreviata Ser.) collected from South Central region of Vietnam

Abstract

Bitter gourds (Momordica charantia L.) have been widely grown and used as a vegetable and medicinal herb to treat diabetes, hepatitis, kidney (stone), cancer, anti-oxidation... as they contain active pharmaceutical substances like glycosides, alkaloids, triterpenes, steroids, and especially saponins with a high concentration. Wild bitter gourds (Momordica charantia L. var. abbreviata Ser.) have higher medicinal properties and resistance than their commercial varieties. However, the number of studies evaluating wild bitter gourd varieties was still very limited. This study aimed to evaluate the agronomical traits and quantify the saponin content of 12 wild bitter gourd accessions collected from the South Central region of Vietnam. The research results showed that 12 wild bitter gourd accessions had a low germination rate (10.34 - 44.19%), various germination time (2 - 20 days), and different first fruit harvest time ranging from 37 to 55 days after planting. The characteristics of leaves, fruits, and seeds differed among collected wild bitter gourd accessions: leaf size (11.90 - 20.23 cm x 9.95 - 16.4 cm), petiole length (3.97 - 8.71 cm), deeply lobed leaf blades with 5 or 7 lobes; fruit size (4.09 - 8.77 cm x 2.05 - 3.5 cm), fruit weight (4.41 - 30.09 g.fruit^‑1), fresh fruit yield (114.84 - 614.045 g fresh fruit.plant^-1); and seed size (9.36 - 13.18 mm x 5.0 - 8.0 mm). The total saponin content ranged from 13.26 to 18.98 mg.g^-1 dry fruit. The BD4 and QN2 accessions were found to have a high yield (614.04 g.plant^-1 and 613.55 g.plant^-1, respectively), which should be used for breeding to enhance their yield. The BD3 and QN3 were found to have a high total saponin content (18.98 mg.g^-1 dry fruit and 16.77 mg.g^‑1 dry fruit, respectively) which should be suitable for breeding research to increase saponin properties.