SALINITY AS A POSSIBLE MEANS OF IMPROVING FRUIT QUALITY IN SLOW-RIPENING TOMATO HYBRIDS

F₁ hybrids of rin and nor tomatoes with normal varieties or with each other yield fruits in which the ripening process is inhibited.
Saline irrigation water enhances the ripening process in tomato fruits.
Thus, we studied whether salinity can improve the quality of these hybrids.

The hybrids were grown in control (l dS·m^-1) or saline (6dS·m^-1 NaCl) nutrient solutions.
At ripening, various ripening, chemical, and physical parameters of the fruits were compared.
Salinity reduced the fruit size in all genotypes.
The juice of fruits from all salt-treated plants had higher contents of sodium, chloride and reducing sugars, and higher values for electrical conductivity and total acidity than the controls, while the pH values were lower.
The CO₂ and C₂H₄ evolution rates, at their peaks during ripening, were higher in fruits from salinized plants than in their controls, for all genotypes.
The taste of fruits from salinized plants was much better than of their controls.
Fruits from salinated plants of hybrids containing rin, nor or both alleles scored higher in taste than fruits from the normal controls.
Fruits of these hybrids contained much less pigmentation than the normal cultivar Rutgers.
Salinity treatment increased the pigment concentration in all these hybrids, but it did not reach the values of the normal Rutgers even in the control treatment.
The fruits of all hybrids were firmer than those of the normal plants.
Salinity treatment reduced the firmness in all genotypes, but the fruits of salinized hybrids were significantly firmer than those of the normal controls.
These differences in fruit firmness were negatively correlated with the total polymethygalacturonase (PMG) activity extracted from similar fruits, i.e., the higher the firmness the lower the PMG activity.

Symposium on Tomato Production on Arid Land

Y. Mizrahi, S. Arad, Y. Mizrahi, R. Zohar

https://doi.org/10.17660/ActaHortic.1986.190.22