Establishment of a plant regeneration system for wheatgrasses (Thinopyrum,Agropyron and Pascopyrum)

Wheatgrasses (Thinopyrum, Agropyron and Pascopyrum spp.) are a ubiquitous group of cool-season grasses used throughout much of the semiarid temperate world. In order to explore the potential of biotechnology to accelerate conventional breeding efforts, we developed an efficient plant regeneration system for different wheatgrass species: tall wheatgrass Thinopyrum ponticum (Podp.) Liu and Wang], intermediate and pubescent wheatgrass Thinopyrum intermedium (Host) Barkw. and D.R. Dewey], crested wheatgrass Agropyron cristatum (L.) Gaertner], and western wheatgrass Pascopyrum smithii (Rydb.) Löve]. Embryogenic callus was induced from mature and immature embryos and immature inflorescence with an induction frequency in the range of 0.5–8.3% for the different wheatgrass species tested. Individual embryogenic calluses were then used to establish single genotype-derived suspension cultures. Efficient plant regeneration was achieved from the established em-bryogenic suspensions with regeneration frequencies in the range of 20–65% for tall wheatgrass, 21–40% for intermediate and pubescent wheatgrasses, 32–51% for crested wheatgrass, and 25–48% for western wheatgrass. The cell suspension-derived wheatgrass plants were fertile and phenotypically normal in the field. The efficient plant regeneration system provides a solid basis for genetic transformation of wheatgrasses.