Search

The Mediterranean region's agriculture is predicted to be severely impacted negatively by climate change. In the primary production region of southern Tunisia (34°43’N, 10°41’E) in olive orchard submitted to different treatments: Rain-fed, drip irrigation with saline water (FI) : EC = 7.5 dS/m at 100% of crop evapotranspiration (ETc), alternate irrigation (PRD) with saline water at 50% of ETc and switched every 30 days, regular deficit irrigation (RDI) with saline water at 50% of ETc, drip irrigation with tap water (TW) : EC=2.46 dS/m at 100% of crop evapotranspiration (ETc), with predicted temperature increases, the effects of climate change and salinity on the floral performance of olive trees were assessed from 2015 to 2017 and the vegetative growth and yield were evaluated over the period. As results, while conserving water in comparison to FI and TW, PRD produced high values for internodes length (1.68 cm) in 2016 and an annual shoot elongation (2.5 cm) in 2015. When comparing flowering (RF) and fruit-setting (RS) rates, olive trees under PRD outperformed those under RDI and FI with (RF=67.52% and RS=7.81%) in 2015. For olive trees exposed to RDI, PRD, and FI, the fruits per unit length were statistically similar in 2015. The use of the PRD technique (50% ETc) yielded good results with an average of 2.96(kg/m3) in our study both quantitatively and qualitatively.

In Tunisia, agriculture is vulnerable to climate change with harmful impacts subsequent warming and drying trends. In these regions, olive industry plays a key role at regional and national level. Therefore, the identification of adapted olive tree genotypes has become an urgent need to develop sustainable agriculture in arid lands. This study aimed to evaluate the impact of climatic variation on the olive growing systems in arid and sub-arid areas of Tunisia. The phenological behavior of Chemlali and Zalmati, main olive cultivars wide spreading in central and southern Tunisia, respectively, were considered to evaluate their capacity to adapt to contrasting climatic conditions. Over the 2005-2019 period, olive cultivars presented variable flowering dates related to local climatic conditions. Zalmati cultivar bloom in Zarzis seems to be earlier than Chemlali cultivar in Sfax region with average flowering dates of DOY-92 (April-3) and DOY-106 (April-17), respectively. A tendency for advancing the growing season was observed with warmer winters, which leads to disruption of pollination, high risk of insect attack, and consequently harmful effects on the production and product quality. This investigation serves as a basis for making recommendations taking into account the production areas as well as for addressing projected climate change.

The Mediterranean region is facing temperature increases due to climate change. More warm conditions across the fruit and nut growing regions are expected to have a great and negative impact in Tunisian arid regions. Chilling trends among the agricultural production areas and their incidence on flowering and fruiting of typical fruit species were investigated. The results showed important declines in winter chill accumulation over the main arid production areas. This lack of chill jeopardizing the flowering and fruiting of fruit species. However, fruit species and cultivars within each fruit species expressed different flowering and fruiting behaviors to warm climate depending on their chilling and heat requirements. Consequently, thermal requirements are a key factor for sustainable fruit trees’ orchards and to select suitable cultivation area. Adoption of appropriate genetic resources could be used to mitigate the harmful effect of global warming in arid regions.