Pollination methods for watermelon (Citrullus lanatus (Thunb.)) fruit setting and yield

Pollination is an essential ecosystem function to sustain food security.
Human made agroecosystem led pollinators to decline which ultimately
reduced fruit setting and yield of watermelon production. A field
experiment was conducted at Manahari Rural Municipality from March 2023 to
July 2023 to study the effect of pollination methods on fruit setting and
yield of two watermelon varieties. The experiment was laid out in two
factorial randomized complete block design (RCBD) having two watermelon
varieties (Saraswati and Vishala) and three pollination methods (bee
pollination, hand pollination, open pollination, and control) which were
replicated thrice. The data regarding foraging activity of domesticated
bee pollinators (Apis cerana F. and Apis mellifera L.) from open field
condition and yield attributing parameters from experimental plot were
recorded. In open field condition, Apis mellifera L. recorded the highest
abundance (5.12 bees/m2/5 min.), foraging speed on male (5.14
second/flower) and female flower (6.17 second/flower). Apis cerana F.
recorded the highest foraging rate (9.31 flowers/bee/min.). The foraging
activity was more active in the morning hours (8-10 a.m.) than at midday
(12-2 p.m.) and evening hours (4-6 p.m.) for both the bee species. From
the experimental plot, variety Saraswati recorded highest number of fruits
per plant (2.52), fruit girth (14.45 cm), fruit weight (1.82 kg), seeds
per fruit (122.53), and yield per plant (4.91 kg) while highest fruit
length (18.58 cm) and 1000 seed weight (49.37 g). The highest fruit set
(74.51%), number of fruits per plant (3.15), healthy fruit (84.83%), fruit
girth (15.81 cm), fruit weight (2.21 kg), seeds per fruit (141.04), and
yield per plant (6.98 kg) were recorded in bee pollinated plots. The
result suggests that the use of A. mellifera bees in the pollination of
watermelon is useful to increase fruit set, production, and
productivity.