González Sánchez, MónicaChiavarino, MauricioJiménez, GManzanero, SIlviaRosato, Carmen Luisa MarcelaPuertas Gallego, María Jesús2024-02-082024-02-082004M. González-Sánchez, M. Chiavarino, G. Jiménez, S. Manzanero, M. Rosato, M.J. Puertas; The parasitic effects of rye B chromosomes might be beneficial in the long term. Cytogenet Genome Res 1 August 2004; 106 (2-4): 386–393. https://doi.org/10.1159/0000793161424-858110.1159/000079316https://hdl.handle.net/20.500.14352/100378Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fertile than 0B ones, whereas the Bs have no significant effects on plant vigour. On the other hand, it has been reported that B transmission is under genetic control in such a way that H line plants transmit the Bs at high frequency, whereas the Bs in the low B transmission rate line (L) fail to pair at metaphase I and are frequently lost. In the present work we analyse variables affecting vigour and fertility considering not only the number of Bs of each plant, but also its H or L status and the B number of its maternal parent. Our results show that the Bs not only decrease female fertility of the B carrier, but the fertility of its progeny, with the exception of 0B plants coming from a 4B mother, which are the most fertile. In this way B chromosomes can be considered as a selective factor. Pollen abortion was higher in B carriers, in the progeny of B carriers and in H plants, but 4B plants coming from B carrying mothers produce less aborted pollen, indicating that a high B number is more deleterious if it is transmitted in the pollen grains. A similar result was obtained for endosperm quality estimated as grain weight, because it is negatively influenced by the Bs in 4B plants coming from a 0B mother. H plants were always less fertile than L ones, indicating that alleles increasing the loss of Bs in the L line will be probably selected as a defence of the A genome against the invasive Bs of the H line. Flower number is not affected by the Bs.engjournal article1424-859Xhttps://doi.org/10.1159/000079316restricted access581.15Genética vegetalBotánica (Biología)Genética2417.14 Genética Vegetal