Branching in red clover (Trifolium pratense): a morphological, physiological and
molecular approach
Annemie Van Minnebruggen1, Isabel Roldán-Ruiz1, Carolien Ruyter-Spira2, Harro
Bouwmeester2, Erik Van Bockstaele1, Gerda Cnops1
Plant Sciences Unit – Growth and Development, Institute for Agricultural and Fisheries
Research (ILVO), Melle, Belgium.
2
Wageningen University, Wageningen, The Netherlands
1
Red clover has several advantages in agriculture: the ability to fixate nitrogen, a high seedling
vigour and a high nutritional value for feed and indirectly for food (high protein and
polyunsaturated fatty acid levels). Plant architecture, which is under genetic and
environmental control, may have a strong influence on agronomic important traits such as
forage yield, re-growth capacity, seed yield and persistence in red clover. We have done an
in-depth study of the architecture of a limited number of red clover genotypes with
contrasting branching phenotypes. A detailed morphological analysis showed differences in
the number of buds, the number of branches, the position of bud outgrowth and bud
outgrowth percentage in the different genotypes. Also, differences were observed in the regrowth after cutting between the genotypes. In a physiological approach, isolated single node
fragments were used to study the influence of branching hormones on bud outgrowth without
having to deal with the complex architecture of a complete red clover plant (non-outgrowing
main axis, many first-order branches). These results will be linked to expression levels of
branching genes. In addition, we determined concentrations of endogenous strigolactones and
auxins in intact plants of the various genotypes. The results demonstrate that both bud
formation and bud outgrowth are important to explain branching differences in red clover.
The importance of the strigolactone and auxin pathways as candidates for further analysis and
molecular breeding for high yielding and more persistent red clover cultivars will be
discussed.