Free Access
| Issue |
Apidologie
Volume 31, Number 1, January-Febuary 2000
|
|
|---|---|---|
| Page(s) | 115 - 128 | |
| DOI | https://doi.org/10.1051/apido:2000110 | |
DOI: 10.1051/apido:2000110
Apidologie 31 (2000) 115-128
Pollinisation de l'artichaut (Cynara scolymus L.) par l'abeille domestique (Apis mellifera L.) en production de semences hybrides sous abris grillagés
Nicolas Morison
,
Bernard E. Vaissière
,
Francis Martin
,
Pierre Pécaut
,
Geneviève Cambon
Laboratoire de Pollinisation Entomophile, INRA Station de Zoologie et
d'Apidologie, 84914 Avignon cedex 9, France
Station de Génétique et d'Amélioration des Fruits et Légumes,
INRA 84143 Montfavet cedex, France
Laboratoire Paleoenvironnements et Palynologie, EPHE, CNRS UMR 5554, ISEM,
Université Montpellier-II, 34095 Montpellier cedex 05, France
(Reçu le 12 février 1999 ; révisé le 27 août 1999 ; accepté le 30 septembre 1999)
Abstract:
Pollination of globe artichoke (Cynara scolymus L.) by honey bees (Apis mellifera L.) to
produce hybrid seed under enclosure. Globe artichoke is currently multiplied mainly by
vegetative means, but the planting of seeds could lead to easier cropping practices and
improved yields. This is especially true with hybrid seeds which could be produced using the
two genetic male-sterility systems available. For two years, we studied the effectiveness of
honey bees as pollinators to produce hybrid seeds of globe artichoke under insect-proof
enclosures. We used two adjacent
m tunnels covered with 1-mm mesh screen and
planted with 2 male-fertile (MF) and 7 male-sterile (MS) lines (tab. I). Each tunnel was
provided with a colony of 3,500 bees at the onset of MF flowering. Flowering of MS and MF
lines was well synchronized (fig. 1), and the number of flower heads per plant was similar
for all lines. Yet, there were over 10-fold differences in both years in the density of
foragers that visited the various lines with extremes of 0.04 to 1.18 honey bees per head
(fig. 2). Some foragers collected pollen, but these were rarely seen on MS heads. The ranking
of MS lines in terms of forager density was similar over both seasons, which suggests that
the differences in attractiveness among these lines were of genetic origin and probably
resulted from differences in nectar availability or composition. Yield of achenes per plant
also varied significantly among lines (fig. 3). The proportion of heads that were empty
ranged from 23% to 100% among MS lines, and for each season was negatively correlated with
the average forager density on each line (fig. 4). The number of achenes per head in the
flower heads which were not empty did not vary significantly among MS lines (tab. II), which
suggests that the pollination effectiveness of honey bee visits was similar among these
different lines. This achene content was greater in MF heads, which is consistent with a
greater pollination effectiveness of honey bees in this inflorescence due to the presence of
pollen and some self-fertility in MF lines. The overall forager density was similar between
the two seasons as was the proportion of empty MS heads, but the achene content of non-empty
MS heads was significantly greater in the second year than in the first one (tab. II). This
suggests that the pollination effectiveness of individual visits was greater in the second
year. Pollen availability was similar in both seasons, but there were 5 times fewer foragers
collecting pollen in the second year compared to the first one. The pool of pollen is limited
when producing hybrid seed, especially in confined environments, and our results suggest that
in these situations the level of pollen collection may negatively affect the pollination
activity of honey bee colonies.
m tunnels covered with 1-mm mesh screen and
planted with 2 male-fertile (MF) and 7 male-sterile (MS) lines (tab. I). Each tunnel was
provided with a colony of 3,500 bees at the onset of MF flowering. Flowering of MS and MF
lines was well synchronized (fig. 1), and the number of flower heads per plant was similar
for all lines. Yet, there were over 10-fold differences in both years in the density of
foragers that visited the various lines with extremes of 0.04 to 1.18 honey bees per head
(fig. 2). Some foragers collected pollen, but these were rarely seen on MS heads. The ranking
of MS lines in terms of forager density was similar over both seasons, which suggests that
the differences in attractiveness among these lines were of genetic origin and probably
resulted from differences in nectar availability or composition. Yield of achenes per plant
also varied significantly among lines (fig. 3). The proportion of heads that were empty
ranged from 23% to 100% among MS lines, and for each season was negatively correlated with
the average forager density on each line (fig. 4). The number of achenes per head in the
flower heads which were not empty did not vary significantly among MS lines (tab. II), which
suggests that the pollination effectiveness of honey bee visits was similar among these
different lines. This achene content was greater in MF heads, which is consistent with a
greater pollination effectiveness of honey bees in this inflorescence due to the presence of
pollen and some self-fertility in MF lines. The overall forager density was similar between
the two seasons as was the proportion of empty MS heads, but the achene content of non-empty
MS heads was significantly greater in the second year than in the first one (tab. II). This
suggests that the pollination effectiveness of individual visits was greater in the second
year. Pollen availability was similar in both seasons, but there were 5 times fewer foragers
collecting pollen in the second year compared to the first one. The pool of pollen is limited
when producing hybrid seed, especially in confined environments, and our results suggest that
in these situations the level of pollen collection may negatively affect the pollination
activity of honey bee colonies.
pollination / Apis mellifera / Cynara scolymus / hybrid seeds / foraging
Correspondence and reprints: Bernard E. Vaissière
vaissier@avignon.inra.fr
Copyright INRA/DIB/AGIB/EDP Sciences