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Title: Understanding genetic and physiological bases of salt tolerance in almond rootstocks

item Sandhu, Devinder
item KAUNDAL, AMITA - University Of California - Cooperative Extension Service
item Ferreira, Jorge
item Suarez, Donald

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Reduced availability of irrigation water is forcing California farmers to use alternative/ degraded waters, which are generally high in their salt content. Almonds are considered sensitive or moderately sensitive to salt. Improving salt tolerance in almond will not only improve yield, but also will provide incentives to make augmented use of alternative/degraded waters, which may open up new lands for almond cultivation. The objectives of this investigation were (1) Evaluation of diverse rootstocks for tolerance to salinity of solutions of mixed salt composition, more representative of available waters than the typical NaCl solutions commonly utilized. (2) Characterization of physiological and biochemical markers associated with salt tolerance and salt composition of irrigation water in almond rootstocks (3) Identification and characterization of genes involved in salinity tolerance in almond rootstocks. We evaluated 16 ungrafted almond rootstocks under five different treatments of waters of mixed ion compositions that included control, sulfate dominant water with mixed cations, chloride dominant water with mixed cations, sodium dominant water with mixed anions, and calcium and magnesium dominant water with mixed anions. There was maximum reduction in trunk diameter when irrigation water was high in Na+ and Cl - suggesting that mostly Na + and to a lesser extent Cl - concentrations in irrigation water are the most critical ion toxicities for almond rootstocks. Photosynthetic rate showed the highest correlation with change in trunk diameter followed by correlations with stomatal conductance and chlorophyll content. Expression analysis revealed that NHX1, SOS3 and AKT1 were highly upregulated in salinity treatments in leaves and HKT1 and AKT1 showed the highest upregulation in salinity treatments in roots. Correlations among gene expression, trunk diameter, and tissue ion concentrations were used to identify the component of salt tolerance mechanism that is the most critical in a particular genotype in almond and that may be manipulated to improve salt tolerance in almonds.