Qualitative and quantitative genetic variations in bitter gourd (Momordica charantia L.)

The testing for distinctiveness, uniformity and stability (DUS) is a prerequisite for release and intellectual property rights (IPRs) protection of new cultivars. Ninety eight bitter gourd genotypes were characterized for 12 agro-morphological traits using DUS guidelines developed by UPOV. Shannon–Wiener diversity index across genotypes varied from 0.00 to 1.32 with mean value of 0.52, demonstrating the adequate phenotypic diversity. Estimates of diversity indices across Indian origins (0.52) and botanical variety, Momordica charantia var. charantia (0.53) genotypes exceeds exotic origins (0.50) and Momordica charantia var. muricata genotypes (0.34). The traits like leaf blade: depth of lobing, fruit color of skin and fruit tubercles were most diverse traits that can distinguish genotypes of bitter gourd. The other traits like sex forms and ridge patterns can be used for identifying and groping of bitter gourd cultivars. The wide variation was also recorded for quantitative traits like node number of first female flower (9.14–27.48), days to first female flower opening (38.62–60.30), days to first fruit harvest (45.68–73.40), fruit length (4.65–21.45 cm), fruit diameter (2.76–6.23 cm), fruit weight (23.14–88.63 g), fruits per plant (12.36–44.40), yield per plant (546.87–2354.51 g) and vine length (118.63–171.28 cm). High heritability for most of the quantitative traits indicated that selection would be effective in improving these traits. This is the first comprehensive study on DUS characterization and identification of a unique trait like white flower (DBGS-54-18) in bitter gourd. The presence of considerable levels of phenotypic variation could be exploited as a source of valuable gene pool for future breeding programme.