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Abstract
SUMMARY
This investigation was carried out at the Branch of Genetic, Department of Agricultural Botany, Faculty of Agriculture (Saba Bacha), Alexandria University, and Genetic Engineering and Biotechnology Research Institute, Menofyia University, Sadat City (GEBRI), throughout the period from 2003 to 2006.
Six tomato cultivars (Lycopersicon esculentum Mill.) (2n=24) were used to conduct the present study. These cultivars were Marglobe, Pakmore, Super Marmande, Castle Rock, Strain B, and Ace.
The study aimed to attainment directly to a procedure for testing suitability of some tomato cultivars for salt tolerance and resistance to wilt disease. Toward this goal, the following was attempted:
1- Establishment callus cultures of six tomato cultivars.
2- Attempt to obtain the ideal combinations of concentrations of the growth regulators that give maximum callus induction.
3- The addition NaCl to the callus culture media with the aim of study adaptation of different calli derived from different cultivars (Super Marmande, Castle Rock, and Strain B) under salinity condition.
4- The addition Fusarium toxin filtrate to the callus culture media with the aim of study adaptation of the calli under such treatment.
5-Trying to regenerate tomato plants through callus cultures after seven successive passages under the high concentrations of the two different treatments.
6- Studing the genetic background differences among different cultivar calli after seven successive passages under the high concentrations of the two different treatments by using biochemical and molecular genetic analysis.
The obtained results of this investigation can be summarized as follows:
1- Three out of six cultivars (Super Marmande, Castle Rock, and Strain B) were chosen to conduct the present investigation, which had white and rhizogenic calli which reflect the high viability of callus.
2- There were differences in degree of callus response or callus success to grow on media. The best combination of Kin and 2,4-D, which gave the highest significantly mean value of callus fresh weight for all studied cultivars, was 1.0 mg/l Kin + 1.0 mg/l 2,4-D. Therefore, the three tested tomato cultivars could ranked based on callus fresh weight as indicator for their callus response or callus success to grow on media in the order:
Strain B > Super Marmande > Castel Rock.
Concerning in vitro adaptation for salt-tolerance, the results indicated that: just one generation of exposure to NaCl treatment especially in the high concentration 6.0g/l reached the treated cultivar to the maximum genetic adaptive value under such treatment. The only responsible agent here is the occurrence of somaclonal through callus induction. This showing that somaclone variation gives kind of genetic variation and some of the produced genotypes from this somaclone had highly