Influence of rootstocks on salinity tolerance of Thompson Seedless grapevines

Salinity is one of the most important abiotic stresses affecting the productivity of the grapes in India. The response of vines differs under such conditions. Dogridge rootstock though introduced in the country to deal with salinity and moisture stress, tolerance was found lacking under such conditions. A study was conducted to evaluate the salinity tolerance of Thompson Seedless vines raised on different rootstocks and on own root at two salinity levels viz., 2 and 4 dSm-1. The rootstocks included were 110R and 1103P from Vitis berlandieri x Vitis rupestris parentage, Dogridge (Vitis champinii) and St. George (Rupestris du Lot). The irrigation water salinity was manipulated using sodium chloride. Thompson Seedless vines raised on 110R and 1103P rootstocks did not show marginal necrosis and leaf blackening symptoms at both salinity levels whereas other rootstocks showed mild to severe symptoms. All stock-scion combinations recorded significantly higher bunch weight than own rooted vines. Highest yield was recorded in the 1103P rootstock at both the salinity levels which was on par with 110R rootstock. Significant differences existed between rootstocks and own root at both the salinity levels with the lowest mean petiole Na values recorded in case of vines raised on 110R. High content of Na in vine tissues (>1.0%) grafted on Dogridge rootstock suggest that this rootstock could not exclude Na under saline irrigation. Though below the threshold levels, at 4 dSm-1 level, Dogridge rootstock recorded significantly higher chloride in petioles than other rootstocks. The sodium potassium ratios in leaf blade and petiole were least in case of 110R and 1103P rootstocks whereas higher values were recorded in case of other stock-scion combinations and on own roots. Highest accumulation of sodium in vegetative parts was recorded in vines grafted on Dogridge whereas the rootstocks 110R and 1103P, accumulated highest K, Mg, Ca and P.