Bitter gourd (Momordica charantia L.) is an economically and nutritionally important vegetable in Asia. The objective of this
study was to evaluate a diverse collection of bitter gourd germplasm for identifying early staminate flowering monoecious
lines for blending with predominantly gynoecious hybrids or gynoecious open pollinated cultivars to provide the pollen
necessary for fruit set. We evaluated 186 cultigens (182 monoecious inbred lines, four commercial hybrids, collectively
referred to as cultigens) of bitter gourd for early staminate flowering (days from sowing to first open staminate flower) in a
two seasons study. The inbred lines were derived from 182 bitter gourd accessions in the collection of AVRDC. Cultigens
were transplanted to the field at the two-leaf stage of growth each season with three plants in each of three replications. The
cultigens differed significantly in both seasons (P<0.05) for mean number of days to first open staminate flowers, which was
affected by season (day length). The earliest staminate flowering cultigen was THMC 62 (Philippines); the latest was THMC
17 (Thailand). Days to 50% staminate flowering and pollen viability (%) of the earliest staminate flowering monoecious lines
ranged from 61.8% to 73.7% and 96.0% to 98.2%, respectively. The early staminate flowering monoecious lines identified
have potential for use as pollenizers to optimize early and total yield of gynoecious hybrids and gynoecious open-pollinated
cultivars.
