Two-year field trial was set up on sandy clay soil in the Jiroft and Kahnouj Agricultural Research Center with the objective to determine the effect of plant spacing and different cultivars on the yield and qualitative characteristics of tomato (Lycopersicon esculentum). This experiment was performed as split plot based on complete randomized block design with 3 replications. The main plots were in -row spacing in 4 levels include 0.3, 0.4, 0.5 and 0.6 m and the subplots were cultivars naming 'Shef ' , 'Peto Early CH' and 'FDT 202' . The results showed that, fruit length to diameter ratio, total acidity, fruit number per plant, mean fruit weight, yield per plant, total yield and first harvest to total harvests ratio were significantly affected by plant spacing. In addition, cultivars showed significant effect on all traits evaluated (p<0.01). In this experiment, fruit length to diameter ratio and total acidity increased as plant spacing increased, however it had no effect on total soluble solids. In this study, total fruit yield is being increased while the yield per plant, number of fruit per plant and fruit weight is being reduced by increased number of plants per unit area. Although among tomato cultivar, 'Peto Early CH' had a higher yield over other cultivars, but cultivar 'Shef ' showed higher yield in the first harvest. Generally it seems according to the results collected that plant spacing 0.3 m and 'Shef ' cultivar owing to better adaptation and higher commercial yield for production in Jiroft city is suggested.

Plants respond to water deficit through several mechanisms. Among which, plant hormones play an important role in induction to abiotic stress tolerance. To bring this issue closer, an experiment was conducted to examine whether salicylic acid (SA) and gibberellic acid (GA3) exogenous applications through foliar spray could alleviate detrimental effects of water deficit on Persian petunia. Treatments consisted of water stress in three levels: 100% field capacity (F.C.) as control, 50, and 25% F.C linked with different concentrations of GA3 and SA sprayed at four levels (0, 100, 200 and 300 mg L–1). Results showed that the dry and fresh biomass, leaf area, photosynthetic pigments levels, relative water content (RWC) and the total number of flowers were significantly (P≤0.01) reduced in response to water deficit. However, free proline concentration and root-to-shoot ratio significantly increased in stressed plants. Plants subjected to severe water stress (25% F.C.), exhibit about 66% stomatal conductance rate lower than the plants grown at 100% F.C. The results showed that SA-treated plants exhibited reduced negative effect of water stress on most of the qualitative and quantitative attributes compared to control, while GA3 application had little impact on studied traits. Importantly, stomatal conductance and RWC were improved in water-stressed plants treated with SA. Moreover, SA-treated plants produced more flowers at all water deficit levels compared to GA3 sprayed plants. It can be concluded that Persian petunia plants respond to water deficit through adaptive changes at biochemical and morphological levels and that adverse effects of water deficit could be alleviated by exogenous application of SA.

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