Effects of Cultivar, Explant Treatment, and Medium Supplements on Callus Induction and Plantlet Regeneration in Perennial Ryegrass

Perennial ryegrass (Lolium perenne L.) is a widely used cool-season grass species as turf and forage. In order to use biotechnological approaches to improve the species, factors affecting tissue culture responses of mature caryopses of perennial ryegrass were studied. Callus induction and regeneration from mature caryopses of thirteen recentlyreleased turf-type perennial ryegrass cultivars were evaluated, and significant differences were found among the cultivars with ‘Roadrunner’ having the highest callus induction and regeneration rates. Callus induction rates increased more than five fold when the caryopses were longitudinally sliced before plating. Callus quality was also improved by this treatment resulting in substantially higher callus regeneration rates. Supplement of BAP (6benzylaminopurine) (0.10.5 mg L-1) in callus culture medium enhanced callus regeneration ability. Copper supplement up to 10 μM in the MS (Murashige and Skoog) medium did not have any effect and 50 μM was toxic. Department of Crop Science, North Carolina State University, Raleigh, NC 27695-7620. *Corresponding author: [email protected]