The present study reports on the effect of humic and salicylic acids on the growth, yield, and fruit quality of three red sweet pepper (Capsicum annuum) cultivars: Barbero, Ferrari, and Imperio. The plants were grown in a greenhouse and the leaves were treated with humic or salicylic acids at 0, 0.5, 1.0, and 1.5 g·L−1 at 20, 40, and 60 days after transplanting. Foliar application of humic or salicylic acids significantly increased vegetative growth, fruit yield, and quality of the three cultivars as compared with the control plants. However, salicylic acid treatment proved more effective than humic acid treatment. Red sweet pepper plants of all three cultivars sprayed with 1.5 g·L−1 salicylic acid showed the greatest vegetative growth; fruit yield components, such as fruit number, diameter, and fresh and dry weights; and fruit quality traits, such as vitamin C content, total soluble solid content, titratable acidity, and total sugar content, than the plants in all other treatments. There were significant differences (P ≤ 0.05) among cultivars in response to humic and salicylic acid foliar application; ‘Ferrari’ showed significantly higher yield and productivity than ‘Barbero’ or ‘Imperio’. ‘Ferrari’ plants sprayed with 1.5 g·L−1 salicylic acid showed the highest fruit weight (202.41 g) and flesh thickness (68 mm), both of which are preferred by consumers, and therefore, have increased market value. This treatment also increased total yield by 27.7% (16.03 t·ha−1), 15.9% (12.38 t·ha−1), and 17.9% (11.88 t·ha−1) in ‘Barbero’, ‘Ferrari’, and ‘Imperio’, respectively. Therefore, salicylic acid foliar application is recommended for enhancing fruit yield and quality of greenhouse-grown red sweet pepper.
Hydroponics is a promising method for cultivation of saffron (Crocus sativus). In this study, saffron corms were sprouted using a gradual decrease in air temperature, and they were cultivated hydroponically in either perlite or volcanic rock for 24 weeks. A nutrient solution was supplied using either an ebb-and-flow system or continuous immersion. First blooming was observed 29 days after transplantation. Among flowering traits, only the stigma length was significantly influenced by the type of hydroponic system. Saffron plants displayed better growth parameters, a higher photosynthetic rate and stomatal conductance (gS), as well as daughter corm (cormlet) production under the continuous immersion system, in comparison with the ebb-and-flow system. Small corms (22–25 mm diameter) did not bloom, and the emergence of flowers increased with corm size. Plant growth and photosynthetic parameters, as well as cormlet production, significantly increased with corm size. We obtained the highest stigma yield [number of flowers (1.9), stigma length (39.4 mm), stigma fresh (42.8 mg), and dry weight (5.3 mg)] and cormlet yield [number of cormlets (5.7), average corm diameter (25 mm), and fresh weight (6.4 g)] using mother corms sized ≥32 mm diameter grown hydroponically in the volcanic rock–based continuous immersion system.