Root and Shoot Formation from Callus Cultures of Tall Fescue1

Abstract

The objectives of this study were to: i) initiate and maintain callus cultures of tall rescue (Festuca arundinacea Schreb. cv. Ky 31); ii) determine the frequency of root and shoot formation after different periods of subculture, iii) establish actively growing plants from these cultures. Calli were initiated from mature embryos on a modified Murashlge and Skoog (MS) medium containing 9 mg/liter of 2,4 dichlocophenoxyacetic acid (2,4‐D). After 28 days, the calli were transferred to a fresh MS medium containing 5 mg/liter of 2,4‐D and incubated for another 28 days before subculturing and testing for root and shoot formation. At this time, each callus was divided and one piece maintained on MS medium with 5 mg/liter of 2,4‐D and another piece placed on a medium with 0.5 mg/liter of 2,4‐D to test for root and shoot formation. This procedure was repeated for two additional subcultures at 28‐day intervals.Results based on more than 800 calli showed that the frequency of calli forming roots was about 45% regardless of number of subcultures. The frequency of calli forming shoots, however, decreased with increasing number of subcultures from 9.6% for the first subculture to 3.1% for the third subculture. A similar decrease was also noted for caili exhibiting both shoot and root formation. The identity of each callus was maintained throughout the entire period from initial plating of the embryo to the final subculture. Of 150 individual calli forming shoots, only 14 did so during more than one subculture period. Only one callus source exhibited shoot formation on all three subcultures. Plantlets and actively growing plants were easily established from calli with shoot formation.