NECTAR PRODUCTION AND FLORAL CHARACTERISTICS IN BIRDSFOOT TREFOIL (Lotus corniculatus L.)

Publisher Website
Google Scholar
Abstract
Nectar production was studied in several varieties of birdsfoot trefoil in relation to flower color, aroma, and some anatomical features in order to identify characteristics which might be of use in a program of selection for attractiveness to honeybee pollinators. Color did not appear to be an important variable; no major varietal differences in light reflectance were noted at any wavelength. There was a twofold varietal range in nectar yield per umbel and a larger difference in potential yield per plant. Selection within varieties increased the difference between high- and low-nectar plants by several times. Large varietal differences in aroma strength were also noted. While nectar and aroma production were not closely correlated in all varieties, those with weak aroma were generally low nectar yielders. Nectar yield per umbel was directly related to the cross-sectional area of functional phloem in the peduncle, and the amount of functional phloem and peduncle diameter were closely correlated. The ratio of nectar yield to phloem supply was much larger in high-nectar than in low-nectar plants, indicating an important effect of an unidentified factor. Preliminary screening in selection for high nectar lines could be facilitated by discarding plants whose flowers have small peduncles and weak aroma.