st

 

st (reduced stipule)

The recessive allele of this gene conditions stipules that have an approximately 80% reduction in surface area. These smaller stipules are also notable in that they are lanceolate in shape, and are often somewhat bent, as seen in the image above. This gene maps right about in the middle of linkage group III, and has been used in the development of a few cultivars. In concert with the af gene which converts leaflets to tendrils, a pea plant with the stgene is called 'fully leafless'. Such plants have extremely reduced photosynthetic surface area, but are especially good at 'standing' in a field without the need of a trellis for support.

The reduced stipule trait was first discovered as a spontaneous event in 1915. In this collection, 16 accessions are described as having the recessive allele, while another six accessions are listed as 'mixed' for this trait. If you would like to query for this mutation, click here.