Yield formation in common buckwheat: Effect of Honeybee Pollination on the Quality and Yield

A field experiment with common buckwheat laid out on Randomized Complete Block Design with three replications was conducted in Kathmandu during 2000-2002. All treatments: Control pollination (CP); Open pollination (OP) and Bee pollination (BP) plots were maintained in the size of 25 sq m with crop geometry of 25 cm X 5cm. Before anthesis, both the CP and BP plots were caged using crop pollination nylon net with the mesh size of 0.827 mm. One Apis cerana F. colony (strength of five frames) was kept inside the cage near the north-west corner of each BP plot. A supplementary liquid protein diet of 1.5% peptone in 50% sugar syrup was supplied to each colony in a frame feeder once in a week throughout the entire pollination period in late evening to intensify the activities of the bee colony and to prevent bees from malnutrition. The OP plots were grown open to permit the natural pollinating insects visit the flowers; fifty plants were randomly selected in each treatment and replication and their biometric measurements were recorded to determine the effect of bee pollination on the crop yield. The quantitative and qualitative effects of Apis cerana F. on buckwheat yield components showed that, yield decreased with large percentage of wrinkled grains set (5.32+0.39) in the CP treatment. The fertility (2.49+0.18%) and harvest index (10.39+0.52%) were also found low in the CP treatment. BP treatment showed significantly enhanced grain set (33.70+0.56) and the total number of grains per plant (169.76+4.10). Fertility percentage was found higher both in BP and OP treatments as compared to CP treatment. It was observed that fertility percentage increased 5 times and grain yield per plant increased by 3 times in BP as compared to CP treatment. Similarly fertility percentage was 4 times higher and grain yield up to 3 times higher in OP than in the CP treatment. Fertility percentage had statistically significant (P=0.01) positive correlation with total number of grains per terminal inflorescence (r=0.683), total number of grains per plant (r=0.179), and harvest index (r=0.274) in the BP treatment.

Key words: Fagopyrum esculentum Moench., Apis cerana F., Fertility, Harvest index, Correlation coefficients.