Evaluation of tolerance of new hybrid citrus rootstocks to salinity

Abstract

In Morocco, citrus fruits are widely cultivated in dry zones and semi-dry areas where the problem of salinity arises and affects the productivity. To face up to this constraint, rootstock remains the most practical means. The Sour orange is widely used in Morocco due to its adaptation to majority of the soils and its acceptable resistance to Phytophthora diseases. However, the majority of associations with this rootstock are sensitive to tisteza virus and impose the search for new citrus rootstock for the replacement of the sour orange. In this regard, a study was conducted to assess the salinity tolerance of nine rootstocks introduced from INRA Corse, which are tristeza-tolerant. Three-month-old plants of each genotype were used. The treatment by the salinity consists of adding two concentrations of NaCl, 2 and 5 g/l, in the solution of irrigation three times a week for two months. The results show that salinity leads to an increase in the severity of symptoms, the concentration of the chloride, and the proline in the leaves. Rootstocks, hybrid 639, Citrumelo Swingle and Mandarin Changsa showed a greater sensibility to salinity. On the other hand, the hybrid Mand Cléo X CC 30576 and Citrange Troyer demonstrate a notable capacity for tolerance to salinity.