fast versatile regeneration of trifolium alexandrinum l.

Abstract Trifolium alexandrinum L. (Egyptian clover) is

one of the most important forage crops in the world. Its

regeneration in tissue culture has been described in a few

reports but the efficiency, accurate time scales and applicability

to various genotypes of the described procedures are

uncertain. Therefore their suitability for genetic transformation

is unclear. In this study, were report new fast procedures

for regeneration of Egyptian clover that are

applicable to the regeneration of various genotypes (Mescawi-

ahaly, Sakha3 and Sakha4). Shoots were regenerated

from intact and wounded cotyledons as well as hypocotyls of

Mescawi-ahaly on naphthaleneacetic acid/benzyladenine

(NAA/BA) and naphthaleneacetic acid/thidiazuron (NAA/

TDZ) media. The highest shoot regeneration frequencies

were obtained from intact cotyledons on NAA/BA

(0.05 mg l-1 NAA combined with 2.0 mg l-1 BA) and

NAA/TDZ (0.05 mg l-1 NAA combined with 1.0 mg l-1

TDZ) media (66.2 and 43.1% respectively) compared to

18.4 and 10.1% for wounded cotyledons on NAA/BA and

NAA/TDZ respectively. 21.0% shoot regeneration frequency

was observed for hypocotyls on NAA/BA

(2.0 mg l-1 NAA combined with 0.5 mg l-1 BA) medium

but no regeneration was obtained on NAA/TDZ medium.

Rooting of the regenerated shoots was induced on indole

butyric acid (IBA: 0.24 mg l-1) orNAA(2.0 mg l-1) media

where IBA medium supported significantly higher frequencies

of rooting as well as survival of the whole plantlets

after transfer to soil. However, the rooting and survival

frequencies also depended on the type of explant and the

medium used for shoot regeneration. The two cultivars