Investigation on the changes of some biochemical traits of almond genotypes leaves under drought stress on the GN15 rootstock

The selection of the appropriate almond cultivars (Prunus dulcis Mill.) in dry and semi-arid regions like Iran in order to produce the optimal product is the importance. In order to study tolerance to water deficit stress, One-year old plants five almond cultivars/ genotypes on the GN15, A factorial experiment was conducted with a RCD which included 3 irrigations factors, 5 genotype factors and 3 replications. Three deficit-irrigation including moderate and severe stress (soil water potential, Ψsoil = -0.8 and -1.6 MPa, respectively) and a control treatment (Ψsoil= -0.33 MPa)  and genotypes/cultivars included: ‘K3-3-1’, ‘H’, ’13-40’, ‘Sahand’ and ‘Ferragness’ grafted on GN15 rootstock in research stations horticulture sahand (Agricultural and natural resources research center of Eastern Azerbaijan).Investigation on growth traits in this study, the number of internod, Proline, protein, total phenol, and total caratnoiede found in the leaves, the percentage of ion leakage (% EL) and chlorophyll fluorescence were evaluated. The results showed that with increasing severity of stress, Proline concentration in cultivar sahand and genotype H (respectively 83.13 and 84. 2 mg/kg) had the highest and genotype 13-40 with 53.65 mg Proline has the lowest. Cultivar ferragnes/ GN15 and 13-40/GN15 had 16.28 and 11.48 mg total protein in leaves. The total amount of phenol in the leaves of almond cultivars from 698 in the treatment control to treatment of severe drought stress to 948 mg equivalent of gallic acid per g. Cultivar Sahand with phenol mg equivalent of gallic acid per g had most activities showed and average percent leakage of electrolytes (% EL) from the 11. 59 to 59% inthe extreme drought stress increased. Severe dehydration stress by increasing the minimum amount of fluorescence and reduce the maximum fluorescence due to reducing the fluorescence rang on the plants and ratio of variable fluorescence to maximum fluorescence (Fv/Fm) from .083 in the control plants to 0. 76 in Sahand leaves .this amount in Ferragness’ leaves from0.81 to 0. 77 was reduced. Therefore, reduction in dry weight, leaf area and number of leaves and increasing special weight of leaves was observed. By reducing the number of internode, the overall growth of young plants reduced. Five cultivars and genotypes on GN15 in moderate stress tension (Ψw =-0.8 Mpa) of were showned tolerance but in extreme stress (Ψw =-1.6 Mpa) , Sahand, Ferragness’ and only partly H genotype were tolerated but two genotypes K3-3-1, and 1340 in severe stress condation showned dehydrated and over 80% of the leaves are falled, and these genotype as the most sensitive and cultivars sahand and Ferragness’  as the most tolerant and Hgenotype with average tolerance to severe stress on the rootstock of the GN15 were diagnosed.