Phenotypic characterization of two under–utilized Teramnus labialis (L.f.) Spreng species grown in Cuba

Teramnus labialis (of the Fabaceae family) is an under-utilized legume with immense potential to improve agricultural soils (through atmospheric nitrogen fixation) and for use as forage for livestock. Despite its pantropical distribution, only a limited number of studies is available to characterize germplasm of this genus. In Cuba, two cultivars are commonly grown, i.e., a light-brown and dark-brown seeded type. The current contribution reports on the phenotypic evaluation of these two cultivars in order to document and characterize plant traits. The results indicated that phenotypic differences were indistinguishable during the early phases of plant growth (up to 45 d), however, after 120–150 d, differences became apparent since the dark-brown seeded cultivar displayed a darker green leaf color and developed numerous epidermal hairs in leaves, petioles and flowers. Examination of the gross anatomical structure of harvested seeds revealed a rougher testa for the dark–brown seeded type compared with the light brown-seeded type. An additional important distinguishing feature was the extended mucro in pods of the light–brown seeded type (5.42 ± 0.13 mm) compared with that of the dark-brown seeded cultivar (3.75 ± 0.08 mm). To our knowledge, this represents the first report of morphological characterization of the two cultivars of T. labialis relevant to Cuba. This information adds to the scant body of knowledge on this under-utilized tropical legume.