Evaluation of Salinity Tolerance of Some Selected Almond Genotypes Budded on GF677 Rootstock

Abstract

In order to evaluate the tolerance of some almond genotypes to salinity, a factorial experiment was carried out based on completely randomized design (CRD), with two factors: genotypes in 11 levels (Tuono, Nonparaeil, Mamaie, Shokoufeh, Sahand, ‘Ferragnès,’ 1–16, 1–25, A200, 13–40 budded on GF677 rootstock, and GF677 (without budding)) and irrigation water salinity in five levels (0, 1.2, 2.4, 3.6, and 4.8 g/l of natural salt (equal electrical conductivity 0.5, 2.5, 4.9, 7.3, and 9.8 dS/m, respectively) and with 4 replication for each treatment in research greenhouse of Seed and Plant Institute in years 2013 and 2014. The results showed that with increasing salinity concentration, growth indicators include the branch height, branch diameter, number of total leaves, percentage of green leaves, leaf density on the main branch, leaf area and leaf area ratio, relative humidity content, chlorophyll index, chlorophylls a, b, total, scion fresh and dry weight, root fresh and dry weight have been reduced in the all genotypes studied, but percentage of necrotic leaves, percentage of downfall leaves, root fresh and dry weight ratio to scion fresh and dry weight, relative ionic percentage, and cell membrane injury percentage of leaves were increased. The results of chlorophyll fluorescence showed that salinity stress affected on the young trees by increasing the amount of minimum fluorescence (FO) and decreasing the maximum fluorescence (Fm) and reduced variable fluorescence (Fv) in the plants and reduced variable fluorescence ratio to maximum fluorescence of 0.83 in the control plants to 0.72 in Sahand cultivar and GF677 rootstock. The result showed that type of scion was affected in obstruction of Na+ absorption by the roots and their transported to leaves, as well as was affected in increasing uptake of K+ by the roots and their transported to leaves. In this research, GF677 is well tolerated to water salinity to 4.9 dS/m but with higher range of salinity showed stress effects. The result showed that type of genotypes budded on GF677 rootstock was very effective in tolerant to salinity. Overall, ‘Ferragnès’ was recognized as the most tolerant cultivar to salinity stress. This cultivar could tolerate salinity 3.6 g/l (Ec: 7.3 dS/m). Also, Sahand was recognized as the most sensitive cultivar to salinity stress.