Adventitious organogenic regeneration from soybean genotypes representing nine maturity groups

In the US, soybean genotypes are classified into maturity groups (MG; total of 13) that represent areas of adaptation generally correlated with latitude bands. To determine if one regeneration procedure could regenerate representatives from diverse areas of adaptation, 18 soybean genotypes representing nine MG were compared for organogenic adventitious regeneration and plant formation from hypocotyl explants following the procedure previously tested on representatives from only three MG. Responding explants were those capable of producing shoots on the acropetal end of the explant from either the outer edge plus central region or the central region only. This enabled determination of the contribution of cotyledonary nodal tissue (outer edge) to shoot regeneration and by discounting those explants, it also enabled estimates of true adventitious regeneration. All 18 genotypes were capable of producing meristemoids/shoots solely from the central region with responses ranging from 28.5 to 64.3% after 4 weeks in culture. All genotypes were also capable of producing elongated shoots that could be successfully rooted. No morphological differences were noted among regenerants, or between them and seed-initiated plants. All regenerants produced viable seed which germinated and produced morphologically normal plants. This study confirmed the genotype- and MG-independent nature of this hypocotyl-based organogenic regeneration procedure and provided conservative estimates for responses that were truly/solely adventitious in nature.