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Performance in seven Allium cepa L. cultivars at different salt stress levels

Abstract:

Performance of seven onion genotypes under saline conditions in sand culture was evaluated since the transplant time. Salt stress was induced with a solution containing CaSO4, MgSO4 and NaCl (1:2.5:3) with electric conductivity (EC) of 6. 8 and 10 dS·m-1, respectively, using a control treatment. Forty days after salt stress being applied, total leaf area, leaf and root biomass were measured, and diameter and fresh weight of the bulb at harvest time. At the level of 6 dS·m-1 ‘Granex-429’ showed lesser leaf area reduction when compared to non treated plants, while in ‘Texas-502’ higher reduction was observed; however, as EC increased the effect was similar in both genotypes. Higher leaf and root biomass percentage was observed in ‘Altagracia’ at 6 dS·m-1; however, these variables were even higher in ‘Granex-429’, ‘Guadalupe’ and ‘Campo Lindo’ at 8 and 10 dS·m-1, while ‘Texas- 502’ and ‘Texas-438’ were more affected in all treatments. Genotypes showed differences in diameter and fresh weight of the bulb only when treated with 6 dS·m-1, being ‘Texas-502’ more severely affected, while ‘Guadalupe’, ‘Granex-429’ and ‘Campo Lindo’ were less affected. Differential performance in genotypes was more evident at EC 6 dSm-1, and ‘Granex-429’ and ‘Texas- 502’ presented the lowest and highest degree of salt sensitivity, respectively.