Monitoring of six grape genotypes in response to salt stress in an arid region in Tunisia: morphological parameters

Abstract

Purpose: This study aimed to valorize the grape genotypes in the oasis of Tozeur, Tunisia, by exploring their salinity tolerance. Research method: The principal genotypes: Arbi, Chetoui, Guelb Sardouk, Kahla, Sfaxi and Muscat d’Italie were subject to two salt treatments: a gradual stress by adding 25 mM NaCl every week until the final doses of 75,100 and 150 mM NaCl and a shock by applying 50 and 100 mM NaCl from the treatment onset. The shoot length and the number of leaves were monitored during salt treatments. Findings: The first mortalities were registered at the 3rd week for Sfaxi under gradual stress conditions, Guelb Sardouk, and Kahla under salt shock. The effects of 75 mM NaCl gradually added were expressed only by the decline of leaves number for the genotypes Chetoui, Kahla, and Sfaxi, while those of low salt shock (50 mM NaCl) were manifested by plant height and leaves number reductions. Salinity damages were aggravated by increasing the salinity. Another response was observed for the studied genotypes: they kept their vegetative apparatus almost unaffected to preserve the photosynthetic capacity. Research limitations: No limitations were founded. Originality/Value: The adverse effects of salinity were more relevant at the end of the stress particularly under the high salt dose (150 mM NaCl). The salinity of irrigation water for our grape genotypes shouldn’t reach 150 mM NaCl. The genotype Arbi was the most tolerant genotype while Kahla was the most sensitive to salinity.

Keywords

• high salinity
• local genotypes
• morphological traits
• oasis
• tolerance