Carbon dioxide enrichment inside a greenhouse is a sustainable approach to increasing crop production worldwide. Recently, the F1 hybrid strawberry became an alternative to runner-propagated cultivation as an innovative method to shorten the production period and increase strawberry production. This work aims to present CO₂ enrichment as a sustainable tool that improves the yield in a controlled greenhouse and addresses the efficiency of three F1 hybrid strawberry varieties grown under Saudi Arabian conditions. A greenhouse experiment was conducted at the National Research and Development Center for Sustainable Agriculture (Estidamah), KSA, to study the impact of two CO₂ levels (400 ppm (“ambient”) and 600 ppm (“enrichment”)) on the growth, photosynthesis traits, fruit yield and fruit quality of three F1 hybrid strawberry varieties grown under soilless culture conditions. The results show that CO₂ enrichment significantly improved the phenotyping of strawberry growth traits at 60 days post-transplanting. The physiological response of the varieties to CO₂ enrichment reveals a significant increase in the photosynthetic rate (129.7%) and intercellular CO₂ (43.7%) in the leaves of strawberry exposed to CO₂ enrichment rather than in ambient conditions, combined with a significant increase in the number of fruits per plant (27.5%) and total fruit yield (42.2%). A similar pattern was observed with varieties D and S in terms of fruit number, length and diameter. However, CO₂ at 600 ppm promoted total soluble solid accumulation and vitamin C for the tested varieties. In contrast, CO₂ enrichment significantly decreased nitrogen, phosphorus, potassium and magnesium accumulation in the leaves of the exposed plants in comparison to 400 ppm of CO₂. These results suggest that increasing CO₂ enrichment could contribute to an increase in strawberry yield and nutritional value and demonstrate that understanding the response of each variety to CO₂ enrichment is important to support selecting suitable greenhouse strawberry varieties to improve crop yield.

The degradation of soil quality due to environmental conditions and improper management practices has caused a shrinkage in land areas suitable for crop cultivation. This necessitates a transition towards soilless culture systems, which offer desirable conditions for crop growth and development and increase resource use efficiency. One of the growth-limiting factors in soilless culture systems is the type of growing substrate. The use of more sustainable resources and environmentally friendly growing substrates is a challenge that affects the soilless culture industry. This work evaluates the efficacy of date palm waste (DPW) and rockwool as growing substrates for sweet pepper (Capsicum annuum L.) under greenhouse conditions. The plant height, stem diameter, average total leaf area, φPSII, and Fm′ of leaf fluorescence show significant increases when plants are grown in rockwool. No differences are found in terms of the total yield or the number of marketable fruits and fruit quality between the two substrates. However, the DPW substrate shows a significant decrease in the number of unmarketable fruits and number of Blossom End Rot (BER) fruits. Plants grown in both growing substrates consume equal water amounts for the optimal fruit production, while the water use efficiency of rockwool is better than that of DPW. Our results highlight DPW’s role in soilless production and as a key solution for resource-saving production systems.

Strawberries are sensitive to abiotic stresses such as salinity, high levels of electrical conductivity, and nutrient imbalances. The mutualistic endophytic fungus Piriformospora indica has significant potential to be used in improving crop production under adverse conditions, with a large host range. However, greenhouse production requires novel tactics to improve the efficiency of saline water irrigation in areas with limited freshwater resources. This study was conducted at the National Research and Development Center for Sustainable Agriculture (Estidamah), KSA, to investigate the impact of P. indica colonization on the growth, photosynthesis traits, productivity, and fruit quality of Fragraria × ananassa Duch cv. Festival strawberry grown in pots and irrigated with two electrical conductivity (EC) nutrient solutions of 1.5 and 3.0 dS/m. The results showed that higher-EC-nutrient solution clearly reduced growth and early yield and improved vitamin C, TSS, and anthocyanin of strawberry in comparison to low-EC-nutrient solution. On the other hand, P. indica colonization significantly increased plant height, shoot fresh weight, root length, and early yield of plants grown under high-EC-nutrient solution with no impact on fruit quality. Obviously, the symbiosis between strawberry roots and P. indica enhanced chlorophyll content, photosynthetic rate, stomatal conductance, and transpiration rate, as well as antioxidant activity such as proline, malondialdehyde, catalase, superoxide dismutase, and peroxidase under higher-EC-nutrient solution. Our study indicated that P. indica might be used as a sustainable tool for strawberry production in arid and semiarid zones, to mitigate the negative impacts of higher-EC-nutrient solution.

Biostimulants enhance plant growth and performance by effectively improving nutrient utilization for sustainable agriculture. Herein, we aimed to investigate the impact of two biostimulants, MiZax3 and MiZax5, on agronomic performance, yield traits, and nutritional quality of saffron (Crocus sativus L.) in two consecutive seasons. We observed a significant increase of 17% and 30% on plant height with foliar application of MiZax3 and MiZax5 at 10 µM, respectively. Application of MiZax3 and MiZax5 at a lower concentration of 5 µM enhanced the number of leaves by approximately 55% and 45%, respectively. Importantly, stigma fresh weight was increased by 59% with MiZax3 at 5 µM in 2023, while the number of flowers plant⁻¹ increased by 117% and 71% with MiZax5 at 5 µM in 2022 and 2023, respectively. In addition, MiZax3 and MiZax5 showed a pronounced positive effect on bioactive compounds in saffron stigmas. We observed a significant increase of 40–98% in crocin with MiZax3 at 5 µM, 48–81% in crocetin, 68–115% in picrocrocin, and 110–151% in safranal contents with MiZax5 at 5 µM over the control. Nutritional analysis further revealed higher contents of carbohydrate, fat, protein, and carotenoid, as well as of calcium, magnesium, iron, and zinc in saffron leaves upon treatment with both biostimulants at 5 µM concentration, demonstrating their biofortification potential. In conclusion, our findings indicate that low concentrations (5 and 10 µM) of MiZax3 and MiZax5 can significantly improve the yield, quality, and nutritional value of saffron, revealing these biostimulants as effective tools for sustainable saffron cultivation. Graphical Abstract