Flowering, nectar secretion and pollen production of some legumes in the Peace River region of Alberta, Canada
Tibor I. Szabo And Henry G. Naida
Twelve cultivars of red clover (Trifolium pratense) differed in numbers of inflorescences/unit area of row, and in nectar secretion characteristics, but not in number of pollen grains per anther. Inflorescences contained from 8.1 to 34.0 μl nectar with sugar concentrations ranging from 33.1 to 49.3% (from 4.4 to 14.8 mg sugar/inflorescence) and from 267 to 554 pollen grains per anther. All cultivars began to flower within 2 weeks of one another and continued over a 12-week period. One cultivar of each of 3 species of alfalfa (Medicago sativa, M. falcata and M. media), one cultivar of each of red clover (T. pratense), alsike clover (T. hybridum), white clover (T. repens) and birdsfoot trefoil (Lotus corniculatus) were compared for numbers of inflorescences per unit area, nectar secretion and pollen production characteristics. Seasonal nectar-sugar production of Altaswede red clover was estimated at 883 kg/ha, compared with estimated yields of 254-558 kg/ha for the alfalfa cultivars. Dawn alsike, Daeno white clover and Leo birdsfoot trefoil had estimated sugar yields of only 44, 24 and 23 kg/ha respectively. The high nectar yields of red clover in the Peace River region should support a substantial increase in numbers of honeybee colonies.