Callus Culture-Derived Somaclonal Variation in the Tropical Pasture Legume Stylosanthes guianensis (Aubl.) Sw.

Plants were regenerated from leaf-derived callus cultures of five genotypes of Stylosanthes guianensis. There were substantial genotypic differences in morphogenetic potential, ranging from 95–100 % of cv.‘Graham' calh to less than 1% of cv,‘Oxley' calh forming shoots. A total of 1024 regenerants (SC₁) were planted out, with 28.1 % surviving to set seed. Variant characters including albinism, reduced fertility, dwarfism and leaf morphology were observed. Variation in selfed progeny (SQ₂) of 138 SC₁ plants was assessed in a replicated field trial involving 2484 SO₂ individuals. Variant phenotypes were observed in 55 (39.9 %) SC₂ families. Many families were segregating for albinism, altered morphology or reduced fertility. Thirty families had lower yields than their parent and earlier and later flowering variants were found. Eight tetraploid families were identified. These were characterized by more erect habit, larger leaves, stems, flowers and seeds, reduced fertility and yield and a tendency to flower later.