Somaclonal variation in soybean plants regenerated from tissue culture

Callus cultures of soybean (Glycine max (L.) Merr.) genotypes PI 88788, PI 438489B, and cultivar Bedford were initiated in vitro from seedling explants consisting of the cotyledonary node plus epicotyl from germinated mature seed. Plants were regenerated from these callus cultures and subsequently evaluated for qualitative variation in three to four subsequent generations. Variant phenotypes observed that have not been previously reported from tissue culture include lanceolate leaves, leaf variegation (chimeral variegated plants), pod variegation on otherwise normal plants, and change in growth habit from indeterminate to determinate. The lanceolate leaf, chimeral variegated plant, and change from indeterminate to determinate growth habit characters were inherited through at least three generations (R0-R2), and segregation occurred in each generation. Pod variegation was inherited through the two generations tested thus far and segregation occurred in each generation. No variation was observed in control plants derived from normal seed. Variants appeared more frequently in regenerants from PI 88788 and PI 438489B than from Bedford. These results confirm and extend the finding that certain tissue culture techniques may be used to induce novel plant formation from somatic tissue of soybean.