The present investigation was carried out during three successive years
(2000· 2002), in order to evaluate three grape cultivars namely, Early Superior, Flame
seedless and Thompson seedless, for salt tolerance under in vitro conditions. The main results can be summarized in the following points: A. Effect of Cultlvars 1· Early Superior gave significantly the highest shoot multiplication percentage and
average number of new proliferated shoots per original shoot, in the 1'1, 2nd and 3^'G
subcultures, followed by Flame seedless and Thompson seedless. In the
meantime, Early Superior achieved significantly the highest leaf P, K, Na, Mg, total
chlorophyll contents and peroxidase activity, followed by Flame seedless and
Thompson seedless. Moreover, Early Superior recorded significantly the highest
leaf N and proline conlents, as compared with Flame seedless and Thompson
seedless. On the contrary, Thompson seedless exhibited significantly the highest
shoot injury percentage and leaf Ca content, followed by Flame seedless an1
Early Superior. Also, Flame seedless cv. exhibited Significantly the highes
average length of new proliferated shoot. 2· Earty Superior produced significantly the highest rooting percentage and average
number of roots per shoot, after 4 weeks of shoot culture, followed by Flame
seedless and Thompson seedless. While, Early Superior and Flame seedless at
the same period gave significantly the highest average root length, as compared
with Thompson seedless. B.Effect of Salinity Treatments 1· In 1", 2"" and 3^rG subcultures, a high decrease in shoot multiplication percentage,
average number of new proliferated shoots per original shoot and average length
of new proliferated shoot and a high increase in shoot injury percentage joined the
increase in salinity concentrations from zero to 4000 ppm. Moreover, leaf N, Na, C\
and proline contents showed a tendency for positive responses to salinitY,
treatments. On the contrary, leaf P, K, Ca, Mg. total chlorophyll contents and
peroxidase activity showed a tendency for negative responses to salinity
treatments. 2· After 4 weeks of shoot culture, rooting percentage, average number of roots per
shoot and average root length showed a tendency for negative responses to
salinity treatments, and the differences among salinity treatments were statistically
significant. It is evident that, Early Superior was the most salt-tolerant cultivar, while
Thompson seedless appeared to be the most satt-sensltive cultivar in this respect. ·Finally, 77%, 70% and 55% of the obtained ptants of Early Superior, Flame seedless
and Thompson seedless, respectively were successfully transplanted to soil. These
plants were healthy and vigorously growing under Ihe greenhouse conditions.