The closed greenhouse is an innovative crop system in the horticulture sector, integrating appropriate climate control equipment and optimized techniques to collect, store, and reuse solar energy for heating and/or cooling the greenhouse. This concept aims to improve the crop yield and quality with energy efficient and water-saving technologies. A specific focus on the opportunities of implementing closed greenhouses under arid climate conditions is detailed in this work. Guidelines for selecting appropriate techniques and design parameters are investigated, aiming for profitable and sustainable greenhouse production. This paper provides an overview of the design aspects of the closed greenhouse and a state of the art of its applications in arid areas. Firstly, the microclimate parameters, including temperature, relative humidity (RH), light intensity, and CO₂ concentration are introduced. Then, an in-depth focus on the effects of these parameters on crop productivity, water, and energy efficiency are thoroughly discussed. Finally, the limitations of closed greenhouse applications are pointed out as opportunities for further research and development in this emerging agriculture field.

During winter 2016, mortality of nearly 25% of in vitro plantlets of 'Garnem' rootstock (Prunus amygdalus × Prunus persica) was observed in a commercial nursery in Tunisia. Plantlets exhibited water-soaked lesions at the crown and roots, girdling the stem and collapsing the whole plants in a few days. 'Garnem' stems (25 plants) with typical symptoms were collected and rinsed with tap water. The margin between healthy and diseased tissue was cut into 0.5 cm pieces, surface sterilized with alcohol (70°), rinsed in sterile water and incubated on ¼ potato dextrose agar (PDA) at 25 °C. Pure cultures were identified as Rhizoctonia solani on the basis of morphological features including right-angled branching of brown hyphae and the presence of sclerotia (Sneh et al. 1991). The internal transcribed spacer (ITS) region of two representative isolates was amplified with ITS1/ITS4 and sequenced (White et al. 1990). The sequences were analyzed using BLAST against GenBank database. The sequences were 98.7% identical to AG 1-IC isolate in GenBank (DQ279032) (González et al. 2016). The sequences were deposited in GenBank as KY964496 and KY964499. Pathogenicity test of the two isolates was conducted on 96 potted healthy plantlets of 'Garnem' rootstock, in a culture room at 25 ± 2 °C and 80% RH. A total of 36 plants / isolate were inoculated by placing one colonized oat grain with each of the two isolates next to the crown. Non inoculated plants served as control. After four days, typical Rhizoctonia stem lesions were observed in 83% of the inoculated plants and R. solani was successfully re-isolated from symptomatic tissues. To our knowledge, this is the first report of R. solani AG 1-IC on Prunus 'Garnem' rootstock nursery in Tunisia.