Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/4/2001
Publication Date: 1/2/2002
Citation: Ferguson, L., Poss, J.A., Grattan, S.R., Grieve, C.M., Wang, D., Wilson, C., Donovan, T.J., Chao, T. 2002. Pistachio rootstocks influence scion growth and ion relations under salinity and boron stress. Journal of the American Society for Horticultural Science. 127(2):194-199. Interpretive Summary: Pistachio trees are better adapted to salinity than most other perennial tree crops. The ability to tolerate adverse water quality creates a niche for pistachio in areas where soils are saline or where a saline water supplies may be utilized for supplemental irrigation. Saline-sodic drainage waters in California's San Joaquin Valley often contain considerable concentrations of boron (B) in addition to increased salts yet little information exists on the interaction of these two stresses in pistachio. Currently, of the three major rootstocks of the California pistachio industry, Pistachia integerrima was significantly less tolerant than the other two rootstocks. Information on differences in the growth of commercial pistachio grafted on rootstock cultivars when exposed to high salt and boron stress will be of increasing importance if these tree species continue to be developed commercially and sustained in areas of marginal soil and water quality.
Technical Abstract: The salt tolerance of pistachio trees (Pistachia vera) on 3 rootstocks of pistachio ( Pistacia integerrima, P. atlantica, and a P. atlantica x P. integerrima hybrid ,UCB-1) were evaluated with 2-year-old trees grown in 1.4 m-cubed sand-tank lysimeters under salinity stress for 6 months. Irrigation with 4 salinity treatments ( 3.5, 8.7, 12, and 16 dS/m) each containing 10 mg/L B resulted in the same salt tolerance ranking (P. atlantica = UCB-1 > P. integerrima) regardless of the growth parameter used for analysis. For a 6-month period of spring and summer growth, the measured salinity resulting in a 50% reduction in trunk diameter increase (TDI) relative to the control TDI was 15.2 dS/m in soil water for P. atlantica. Total tree biomass and leaf area trends were similar to those for diameter. For P. atlantica, the salinity where a 50% reduction in biomass occurred (15.4 dS/m) was not significantly different from the salinity where a 50% reduction in biomass for the UCB-1 hybrid was observed (15.4 dS/m). P. integerrima was significantly less tolerant than the other 2 rootstocks and the 50% reduction in TDI, relative to the control, occurred at 12.9 dS/m. Transpiration and stomatal conductance, determined by steady-state porometry, were reduced to a greater degree by salinity in the P. vera x P. integerrima combination than P. vera on the other 2 rootstocks. Chlorophyll contents estimated with a SPAD meter indicated lower concentrations of chlorophyll for leaves of P. vera on P. integerrima that is associated with a greater degree of foliar injury compared to P. vera on the other 2 rootstocks.