Stepwise decrease of 2,4-D and addition of BA in subculture medium stimulated shoot regeneration and somatic embryogenesis in buffalograss

Abstract

Plant regeneration of buffalograss `Texoka' was achieved through both somatic embryogenesis and organogenesis by culturing immature male inflorescences collected from field-grown plants. Three passages of subculture for calluses derived from male `Texoka' on medium containing 2.25, 4.5, or 9 μM 2,4-D combined with either 0.44 μM or 1.32 μM BA led to shoot formation via organogenesis. Higher concentrations of 2,4-D (4.5 or 9 μM) resulted in higher percentages of embryogenic callus while 2,4-D at 2.25 μM generated shoot-producing callus but with a lower percentage of embryogenic callus. Transfer of calluses from medium containing 4.5 μM 2,4-D and 0.44 μM BA to the somatic embryo initiation medium containing 0.9 μM 2,4-D gelled with either 7 g 1−1 agar or 3 g 1−1 Gelrite led to the formation of somatic embryos. Somatic embryo initiation medium gelled with 3 g 1−1 Gelrite led to significantly higher frequency of somatic embryo formation than in medium gelled with 7 g 1−1 agar. Callus of a female genotype `315' generated under similar treatments did not produce shoots or somatic embryos.