Diversity of nutrient and nutraceutical contents in the fruits and its relationship to morphological traits in bitter gourd (Momordica charantia L.)

Bitter gourd (Momordica charantia L.), a tropical vegetable crop, has long been used as a food and medicine. Its unripe fruits have anti-diabetic properties due to charantin, a typical cucurbitane-type triterpenoid. The present study aimed to determine diversity in different nutrient (β-carotene and ascorbic acid) and nutraceutical (chlorophyll, total phenols, phenolic acids, flavonoids, radical scavenging activities and charantin) content of matured but unripe fruits of five diverse genotypes and their association with different morphological characters (leaf colour, tendril character, sex form, fruit colour, fruit shape, tubercle character, fruit length, fruit girth and fruit weight) through heat mapping and regression modelling in order to determine the key characters influencing them. The genotypes differed significantly for most of the morphological traits, nutritional and nutraceutical contents and the predominant types of Indian origin (dark green, spindle shaped fruits with sharp tubercles) were associated with high nutrient and most of the nutraceutical contents but comparatively low in charantin content. The predominant types in the region of China, Japan, Indonesia, Korea (whitish yellow, yellowish white, obtuse or roundish-oblong fruit with light ridges or roundish blunt tubercles) were associated with comparatively low nutrient and most of the nutraceutical contents but high in charantin content. Association study identified the morphological characters influencing the phytochemical contents and regression modelling predicted relative significance of those morphological characters on the different nutrient and nutraceutical contents. The study confirmed the effectiveness of combining morphological characters with nutrient and nutraceutical contents that can be utilized to develop functionally rich bitter gourd genotypes.