RESPONSES TO NACL STRESS OF CULTIVATED AND WILD TOMATO SPECIES AND THEIR HYBRIDS IN CALLUS-CULTURES

If in vitro culture is to be used for evaluating the salt tolerance of tomato hybrids and segregant populations in a breeding programme, it is previously necessary to get quick and reliable traits. In this work , growth and physiological responses to salinity of two interspecific hybrids between the cultivated tomato (Lycopersicon esculentum Mill) a nd its wild salt-tolerant species L. pennellii are compared to those o f their parents. The leaf callus of the first subculture was grown on media amended with 0, 35, 70, 105, 140, 175 and 210 mM NaCl for 40 day s. Relative fresh weight growth of callus in response to increased sal inity in the culture medium was much greater in L. pennellii than in t he tomato cultivars, and greater in the hybrids than in the wild speci es. Moreover, the different salt tolerance degree of hybrids was relat ed to that of female parents. At high salt levels, only CT accumulatio n was higher in L. pennellii than in tomato cultivars, whereas in the hybrids both Cl-, and Na+ accumulation were higher than in their paren ts. Proline increased with salinity in the callus of all genotypes;the se increases were much higher in the tomato cultivars than in L. penne llii, and the hybrids showed a similar response to that of the wild sp ecies. Salt-treated callus of the tomato cultivars showed significant increases in valine, isoleucine and leucine contents compared to contr ol callus tissue. In contrast, these amino acids in callus tissues of the wild species and hybrids showed a tendency to decrease with increa sing salinity.