EFFECT OF 6-BA ON REGENERATION OF SOYBEAN COTYLEDONARY NODE Agrobacterium-mediated Transformation of Soybean Germinating Cotyledonary Node Cells High-efficiency Agrobacterium-mediated Transformation of Soybean Study of the Agrobacterium-mediated Transformation Systems of Soybean Cotyledonary Node Conditions of Co-Culture Affecting on the Efficiency of Agrobacterium-Mediated Transformation of Cotyledonary Node of Soybean