POLLINATOR’S DENSITY ASSESSMENT ON LITCHI AND SWEET GOURD FLOWER AND THEIR CONTRIBUTION TO YIELD

In the present experiment, the population density of insect pollinators and their influence on the fruit yield of litchi and sweet gourd were studied near Hajee Mohammad Danesh Science and Technology University campus, Dinajpur, Bangladesh from November 2019 to August 2020. Two treatments: open and net-pollinated plots were established in litchi orchards and sweet gourd field. Insect pollinator's diversity was observed from 8.00 am to 16.00 pm with the interval of 2 hours for three successive weeks from the initiation of flowering until approximate 95% of the flower faded. Altogether 8 species of insects' pollinators belonging to 2 different orders and 6 families in both litchi and sweet gourd flowers were recorded. Among them, Apis dorsata was recorded the most important pollinator in both litchi (47.93) and sweet gourd (49.53%). The peak foraging activities of majority of the insects were detected from 10.00 to 12.00am in both crops. Significant differences were observed on reproductive parameters of litchi and sweet gourd on open-pollinated over netted treatments. The increased yields were found in both opened pollinated litchi plants and sweet gourd than netted plants. Fruits inflorescence-1 and fruits weight inflorescence-1 (gm) were increased as 171.31 and 197.05%, respectively in open-pollinated litchi plant over netted plant. Similarly, single fruit weight, number of seeds and seed weight fruit-1 were increased as 200.00, 212.86, 216.38%, respectively in open-pollinated plant over netted sweet gourd.