|KAUNDAL, AMITA - University Of California - Cooperative Extension Service|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/4/2018
Publication Date: N/A
Technical Abstract: The reduced availability of good quality irrigation water has led to increased use of water of high salinity. As almonds are 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. To understand underlying genetic and biochemical mechanisms for the salt tolerance process, we evaluated 16 commercial almond rootstocks under 5 different compositions of irrigation water 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. Plants under salinity (3 dS m-1) resulted in significant reductions in trunk diameter, chlorophyll SPAD (SPAD), photosynthetic rate (Pn), stomatal conductance (gs), transpiration (Tr) and water use efficiency (WUE) as compared to the control. Photosynthetic rate showed the highest correlation with change in trunk diameter followed by correlations with stomatal conductance and chlorophyll content. Irrigation with waters of different compositions revealed that sodium and chloride were the predominant ions affecting plant performance under salinity. The expression analyses revealed that most of the genes involved in salinity stress were upregulated in treatments that contained Na and/or Cl as predominant ions, confirming the importance of both Na+ and Cl+ toxicities during salinity stress. Correlations among gene expression, trunk diameter, biochemical markers and tissue ion concentrations allowed us to identify the component traits for the salt tolerance mechanism that are the most critical in a almond genotype. The comprehensive understanding of the salt tolerance mechanism may become instrumental in improving salt tolerance in almonds.