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 Printable version |
Study of the use of alternate strips for the production of semi-dwarf
hybrid colza seeds in the presence of bees |
Oléagineux, Corps Gras, Lipides. Volume 6, Number 4, 343-8, Juillet - Août 1999, Fondamental
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 Résumé
Article gratuit
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Author(s) : Jacqueline PIERRE, Jacques MESQUIDA,
Michel RENARD, Patrick VALLEE |
Summary : Two designs were set up to produce semidwarf hybrid seeds of oilseed rape and were tested for pollination efficiency. In both cases the male-fertile/male-sterile ratio was 2/13, so that the most distant male-sterile strip was 19m away from the male-fertile strip. In 1991, the male fertile line was dwarf, whilst in 1995 the male-sterile line was dwarf. The male and female lines differed in height up to 90cm. Pollinating entomofauna (with hives addition) and yield components were studied. In 1991, the floribundity of the two lines was much higher than in 1995, but their flowering time were well synchronized in both designs. The proportion of solitary bees, bumblebees and dipterans were different according to the year but the addition of hives led to a drastic predominance of the honeybee population. Pollen gatherers stayed on the male-fertile strip and their density/1000 flowers was particularly high in 1991. That can be partially attributed to a « corridor effect » of the dwarf male-fertile strip. Nevertheless, even if the difference in height reduces the number of shiftings between the lines, it does not completely stop them. No gradient in the nectar gatherers density was detected in relation to their distance from the male-fertile strip. Considering the yield components in each design, no very significant differences were found between male and female lines. They had no incidence on the final yield except for the male-fertile line when this one was dwarf and suffered from the competition with tall male-sterile line. In both cases, the male-sterile lines yield was always higher than male-fertile ones and was independent of their distance from the male strip. Consequently, both designs can be used. Nevertheless such results only concern the Basin of Rennes where the climatic conditions are favourable to hybrid seed production with pollinating insects. A confirmation of these preliminary results in other regions is needed. |
Keywords : rapeseed, hybrid seed, semi-dwarf, insect pollination. |
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