Salt Tolerance of Grape Rootstocks Under Greenhouse Conditions

¹ Department of Soil and Water Science, University of Arizona, Tucson, AZ 85721.

Seven grape rootstocks were grown in soil columns irrigated with three levels of salinity, EC of 0.45, 2.5, and 5.0 dSm^-1. The latter two waters were prepared by adding MgSO₄ and CaCl₂ salts to tap water with EC of 0.45 dSm^-1. Shoot growth, pruning weight, leaf area, and trunk diameter were significantly reduced by salinity. Reduction in shoot growth and pruning weight were more pronounced than leaf area and trunk diameter. Total cations and chloride accumulated in the leaves of grapes were different between rootstocks. Maximum EC_e values (100% reduction in growth) varied from 8.9 dSm^-1 for 41B to 16.4 dSm^-1 for Salt Creek. Maximum EC_e for Barbera (Vitis vinifera) was 11.1 dSm^-1. On the average, there was an 8.4% growth reduction for each 1.0 dSm^-1 increase in salt concentration above a threshold value of 1.1 dSm^-1. Based on percent reduction in growth, the relative tolerance of grape rootstocks could be arranged as follows: Salt Creek and 5BB > SO4 and 1613 > 110R and Barbera > 41B. Submitted on October 17, 1985