Regeneration of Bermudagrass Cultivars and Evidence of Somatic Embryogenesis1
- B. J. Ahn,
- F. H. Huang and
- J. W. King2
Plant regeneration via somatic embryogenesis is a prerequisite to utilizing in vitro culture techniques for improving bermudagrasses. This study was conducted (i) to apply the culture methods, previously developed for common bermudagrass [Cynodon dactylon (L.) Pers.], for plantlet regenerations from a genotypic array of bermudagrasses, (ii) to determine a mode of the regeneration, and (iii) to establish and characterize cell suspension cultures. Embryogenic calli (EC) were produced from immature inflorescences of ‘Tifton 44’, ‘74 ✕ 12-6’, and ‘Tifway’ bermudagrass on N6 agar medium supplemented with 1 mg L-1 2,4-D (2,4-dichlorophenoxy acetic acid). The EC were maintained for over 30 weeks (140 weeks in common bermudagrass) without loss of embryogenic competence by subculturing to fresh medium. Plantlets were regenerated 2 weeks after the EC were transferred to auxin-free N6 medium. Histological observation of regenerating EC confirmed plant regeneration through somatic embryogenesis in common bermudagrass. Suspension cultures of common bermudagrass were composed of mostly vacuolated, tubular, single cells or cell aggregates that formed only nonembryogenic calli when cultured in N6 agar medium (0.5 mg L-1 2,4-D, 8 g L-1 agar). Small, cytoplasmically rich embryogenic cells were found mostly in compact cell clumps that developed globular embryoids in suspension with 0.25 mg L-l 2,4-D. The clumps produced numerous plantlets upon transfer to regeneration medium. These cultural methods can be useful to genetically improve forage and turf-type bermudagrass species for desirable agronomic traits.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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