ISHS Acta Horticulturae 288: VI International Symposium on Pollination
QUANTITATIVE AND QUALITATIVE ANALYSIS OF RAPESEED FLOWER NECTAR (BRASSICA NAPUS L. VAR. OLEIFERA METZGER) |
| Authors: | M.-H. Pham-Delègue, J. Mesquida, R. Marilleau, M. Le Métayer, M. Renard |
| Abstract:
The production of Fl hybrids using male sterility implies the need of equalized pollinators distribution - honeybees mostly - between male sterile and male fertile lines in field crops. In this respect, quality and quantity of nectar production may be significant for selective foraging behavior in the honeybee. Therefore we have first conducted experiments to compare two nectar extraction techniques, micropipetting and centrifugation, to establish a reliable basis for analysis and comparison of nectar production of rapeseed lines under selection. All tests used "Kid" cultivar. Nectar sugar composition was assessed by gas chromatography. Centrifugation appeared to artificially dilute nectar and produce samples unrepresentative of those actually encountered by insects. Glucose and fructose fractions were very similar using either method. Micropipetting was therefore recommended for future work. We then focussed on the comparison of the nectar secretion of 5 cybrids (cytoplasmic male sterility, Ogura (1968), improved by protoplast fusion, Pelletier et al. (1983)) and of the "Darmor" variety. Samples were collected using pipetting method and the analysis of their sugar composition was performed by high pressure liquid chromatography. It appeared that, although great fluctuations might occur in the amounts of nectar, the sugar composition of the cybrid nectars were constant and acceptable for entomophilous pollination purpose. | |
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