Evaluation for salt stress tolerance of pepper genotypes to be used as rootstocks

Salinity is a major environmental constraint on crop productivity and grafting can be a sustainable strategy to enhance plant tolerance under adverse growth conditions. Screening different graft combinations under field conditions can be a slow and expensive processes. In this study, plants of 18 genotypes of Capsicum spp. were evaluated during 5 months to select salt tolerant plants to be used as rootstocks in greenhouse under controlled conditions. Their net photosynthetic rate was used as a rapid and sensitive methodology for screening their tolerance to salt stress conditions. The germination potential of some genotypes was also tested under different salinity conditions to see if it would be useful to accelerate the screening process. According to photosynthesis rate, the commercial rootstock ‘Tresor’ and the genotypes ‘Serrano’ (C. annuum), ‘ECU-973’ (C. chinense) and ‘BOL-58’ (C. baccatum) were the most tolerant during this period. Nevertheless, the evaluation of pepper genotypes for salinity tolerance based on the germination performance and chlorophyll fluorescence parameter Fv/Fm ratio were not good indicators of the sensitivity along plant ontogeny. Finally, the selected genotypes as salt-tolerant were validated under field conditions as rootstocks of two interesting pepper cultivars, concluding that using the rootstocks selected by the net photosynthetic rate improved the salt tolerance of the scion in terms of marketable yield and fruit quality.