Salinity Effects on Seed Yield, Growth, and Germination of Grain Sorghum1

Abstract

AbstractGrain sorghum (Sorghum bicolor(L.) Moench] is grown on saline soils in the western United States. Because of the lack of information on salinity effects on seed yield, a field plot study was conducted. Six saline treatments were imposed on a Holtville silty clay (clayey over loamy montmorillonitic (calcareous), hyperthermic Typic Tor‐rifluvents) by irrigating with waters that were salinized with NaCl and CaCl2(1:1 by wt). The electrical conductivities of the irrigation waters were 1.5, 2.7, 5.0, 7.4, 9.8, and 12.1 dS/m. Germination, vegetative growth, and grain yield were measured. Relative grain yield of two cultivars, Double TX and NK‐265, was unaffected up to a soil salinity of 6.8 dS/m (electrical conductivity of the saturation extract: Κe). Each unit increase in salinity above 6.8 dS/m reduced yield by 16%. This indicated that grain sorghum is moderately tolerant to salinity. Yield reduction was due primarily to lower weight per head rather than a reduced number of heads. Vegetative growth was affected less by increasing soil salinity than was grain yield. Grain sorghum was significantly more salt tolerant at germination than at later stages of growth.