
TY  - JOUR
A1  - Lawrence, M.E. 
T1  - <I>Senecio</I> L. (Asteraceae) in Australia: Rcombination systems of a polyploid series
JF  - Australian Journal of Botany
JO  - Aust. J. Bot.
Y1  - 1985
VL  - 33
IS  - 2
SP  - 209
EP  - 219
KW  - 
UR  - https://doi.org/10.1071/BT9850209 
N2  - Recombination systems of 32 species of Senecio are discussed in terms of chromosome number, chiasma frequency and position, breeding system and generation length. Darlington's recombination index cannot be applied to Senecio as several ploidy levels are represented. Increases in basic chromosome numbers promote recombination but increases by polyploidy buffer intermediate genotypes and retard evolutionary changes when selection is for homozygous or extreme phenotypes. High polyploid species of Senecio may therefore have recombination systems as restrictive as those produced by aneuploid reduction. When viewed in this manner, the majority of native species examined have recombination systems that contain a balance of restrictive and expansive factors regulating recombination. 
ER  -

