Vegetative Propagation of Temperate Forage Grasses through Callus Culture1

Abstract

Five temperate forage grass species, creeping foxtail (Alopecurus arundinaceus Poir.), crested wheatgrass (Agropyron cristatum (L.) Gaertn.), green needlegrass (Stipa viridula Trin.), smooth bromegrass (Bromus inermis Leyss.) and western wheatgrass (Agropyron smithii Rydb.) were cultured in vitro. Callus was initiated from segments of young inflorescences of each species cultured in the dark at 25 C on Linsmaier and Skoog (RM) or Gamborg, Miller, and Ojima (BS) medium supplemented with 5 mg of 2,4‐dichlorophenoxyacetic acid (2.4‐D) combination with 0 or 0.2 mg kinetin/liter. All of the calluses subcultured on RM medium unsupplemented with hormones in the dark at 25 C developed plantlets via organogenesis. An addition of 1 mg kinetin/liter to the basal medium enhanced shoot initiation in calluses of western wheatgrass, green needlegrass, and creeping foxtail. Regenerated plants were subsequently established in soil.Albinism was noted among the regenerated plantlets of smooth bromegrass, creeping foxtail, crested wheatgrass, and green needlegrass. The relative frequency of albino plantlets emerging from a callus tended to increase with age of the subculture. Albinism was reduced in calluses differentiating on RM medium containing 1 mg kinetin/ liter, possibly due to improved plastid formation.All of the calluses were maintained on RM medium supplemented with 5 mg 2,4‐D/liter. Improved growth of green needlegrass callus was obtained by supplementing the above medium with 0.5 mg of kinetin/liter.Two warm‐season grasses, big bluestem and Indiangrass, have previously been shown to respond to the same general tissue culture methods used in the present study. This suggests that these methods may have general applicability for forage grass species.