Meiosis disturbances, aneuploidy and seed fertility in Raphanobrassica

Abstract

Meiosis was studied in one F2- and one F7 population of the amphidiploid hybrid Raphanobrassica, the F7-population being the result of uninterrupted fertility selection. Univalents at M1 and laggards and bridges at A1 and AII are frequent, resulting in aneuploid gametes and plants. These disturbances are supposed to be caused by insufficient meiotic timing between the parental genomes, i.e. the same explanation as has been given for similar disturbances in triticale. There are no indications that repeated selection resulting in improved seed fertility has any influence on the rate of disturbances at meiosis. Meiosis appears to be only slightly influenced by external factors, while seed fertility is considerably influenced. The best seed fertility so far obtained from material grown in greenhouses in SvalOv is 31 %. A seed fertility of 43 % has been obtained from the same material when grown in the field in Spain. Raphanobrassica has potentials to become an interesting annual fodder crop if an economic seed production can be made possible through further improvements of seed fertility and by a proper choice of propagation sites. The population will, however, still be impaired by the same meiotic irregularities as the present material of Raphanobrassica.