Abstract: A method is provided for regenerating cotton plants from explant tissue. The improved method allows the generation of embryogenic callus from a cotton tissue explant which is not cultivated on cotton initiation media having exogenous plant hormones. The method can be utilized in the transformation of cotton plants, by cutting cotton tissue to form an explant, co-cultivating the cotton explant tissue with Agrobacterium comprising a DNA sequence of interest, and culturing the co-cultivated explant on cotton initiation media comprising a selective agent but having no exogenous plant hormones. In this fashion transformed cells are induced to produce embryogenic callus on hormone-free selective media.

Abstract: Methods and compositions are provided to improve the quantity of embryos obtained by induction of somatic plant tissue. These involve the addition of effective amounts of selected amino acids, their derivatives or combinations of these as a source of reduced nitrogen, together with an optimum auxin dosage to the nutritive media used to regenerate or maintain the embryonic tissue. A synergistic effect is found by adding these amino acids either in combination or in combination with ammonium ion together with the selected auxin dosage.

Abstract: Methods and compositions are provided for the growth of cultured plant cells which include the addition of maltose as a carbohydrate source. Additional improvements in the plant cell growth medium can be obtained by adding a source of ammonium ion to the medium to obtain a synergistic effect with the maltose.