Increasing salt tolerance in tomato

In this paper, a number of strategies to overcome the deleterious effects of salinity on plants will be re-viewed; these strategies include using molecular markers and genetic transformation as tools to de-velop salinity-tolerant genotypes, and some cultural techniques. For more than 12 years, QTL analysis has been attempted in order to understand the genetics of salt tolerance and to deal with component traits in breeding programmes. Despite innovations like better marker systems and improved genetic mapping strat-egies, the success of marker-assisted selection has been very limited because, in part, of inadequate ex-perimental design. Since salinity is variable in time and space, experimental design must allow the study of genotype3environment interaction. Genetic trans-formation could become a powerful tool in plant breeding, but the growing knowledge from plant phys-iology must be integrated with molecular breeding techniques. It has been shown that the expression of several transgenes promotes a higher level of salt tolerance in some species. Despite this promising re-sult, the development of a salt-tolerant cultivar by way of transgenesis has still not been achieved. Future directions in order to overcome the present limitations are proposed. Three cultural techniques have proved useful in tomato to overcome, in part, the effects of salinity: treatment of seedlings with drought or NaCl ameliorates the adaptation of adult plants to salinity; mist applied to tomato plants grown in Mediterranean conditions improves vegetative growth and yield in sa-line conditions; and grafting tomato cultivars onto ap-propriate rootstocks could reduce the effects of salinity