Morphologie comparée de grains de pollen chez "Brassica juncea" (L.) Czern. et Coss., "Brassica nigra" (L.) Koch et "Brassica rapa" L.

Résumé

The aim of this study was to measure pollen size in diploid and autotetraploid genotypes of Brassica nigra and B. rapa, and the results were compared with the allotetraploid B. juncea. In the two diploid species, autotetraploidisation was responsible for a significant increase in pollen size, similar to allotetraploids. The increase in pollen width was twofold (32-40%) that of the pollen length (18-20%) when the chromosome number was doubled (from 2x to 4x, or 4x to 8x); 2n pollen had 3 pores while 4n pollen sometimes exhibited 3 or 4 pores. These results could be useful for identifying 2n pollen producers in diploid Brassica sp., with a view to obtaining tetraploid genotypes by gametophytic crosses.