PLANT-REGENERATION OF PAMPAS GRASS FROM IMMATURE INFLORESCENCES CULTURED INVITRO

A micropropagation system to obtain plants from inflorescences of pampas grass (Cortaderia selloana Schult. 'Pumila') was developed. Factors examined included developmental stage of inflorescence cultured and growth regulator combinations and concentrations that support explant establishment, shoot regeneration, and rooting. Immature inflorescences almost-equal-to 300 mm long formed many shoot primordia when initially cultured on Murashige and Skoog basal medium containing 4.5-mu-M 2,4-D and 8.9-mu-M BA and subcultured to medium with 0.4-mu-M 2,4-D and 4.4-mu-M BA. Thereafter, monthly transfer to a medium without growth regulators yielded about three shoots per tube per month for more than 6 months. Most shoots rooted spontaneously and were easily hardened to greenhouse conditions. Field-tested plants flowered within 2 years and nearly all appeared identical to the parent cultivar. With this technique, several thousand plants can be obtained from a single inflorescence in 1 year. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine (BA); (2,4-dichlorophenoxy)acetic acid (2,4-D).