| Abstrakt: |
Abstract  The turf-type bermudagrasses are genetically variable and do not respond uniformly to tissue culture and plant regeneration protocols. We evaluated the callus induction response of two explant types, young inflorescences and nodes, from multiple genotypes including triploid TifSport, TifEagle, and Tift97-4 and tetraploid Tift93-132, Tift93-135, Tift93-156 and Tift93-157 on MS medium supplemented with 1â1.5 mg lâ1 2,4-D  0.01 mg lâ1 BA  1.16 g lâ1 proline. Four types of callus were observed. Type I was fluffy, soft, and white non-embryogenic callus, common to all cultures. Type II was globular, transparent, and hard, but sticky callus, which was pre-embryogenic and could be selected for subculture. Type III callus was transparent, compact, and embryogenic. Type IV callus was opaque white and compact. Both Type III and Type IV calluses were embryogenic and regenerative. A combination of gelling agents in the medium (2 g lâ1 Gelrite and 5 g lâ1 agar) improved callus quality and increased the rate of compact callus formation during subculture. Embryogenesis from compact callus was observed in TifEagle, TifSport and Tift93-132, and shoots were regenerated on MS medium with 0.1 mg lâ1 2,4-D  0.5â4.0 mg lâ1 BA. Low intensity light treatment (30 μmol mâ2 sâ1 of cool white fluorescence) to callus before regeneration greatly enhanced regeneration frequency from 6.7% to 40% in recalcitrant TifSport. [ABSTRACT FROM AUTHOR] |
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