Effect of Salinity on Grain Yield and Quality, Vegetative Growth, and Germination of Semi‐Dwarf and Durum Wheat¹

Abstract

Semi-dwarf bread wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum L., Durum Group) are often grown on saline soils in the western United States. Because of the lack of information on salinity effects on vegetative growth and seed yield of these two species, a 2-yr field plot study was conducted. Six salinity treatments were imposed on a Holtville silty clay (clayey over loamy, montmorillonitic (calcareous), hyperthermic Typic Torrifluvent) by irrigating with waters salinized with NaCI and CaCI, (1:1 by wt). Electrical conductivities of the irrigation waters were 1.5, 2.5, 5.0, 7.4, 9.9, and 12.4 dS/m the first year, and 1.5, 4.0, 8.0, 12.0, 16.1, and 20.5 dS/m the second year. Grain yield, vegetative growth, and germination were measured. Relative grain yields of one semi-dwarf wheat cultivar and two durum cultivars were unaffected by soil salinity up to 8.6 and 5.9 dS/m (electrical conductivity of the saturatedsoil extract), respectively. Each unit increase in salinity above the th~esholds reduced yield of the semi-dwarf cultivar by 3.0% and the two durum cultivars by 3.8%. These results place both species in the salt-tolerant category. Salinity increased the protein content of both grains but only the quality of the durum grain was improved. Vegetative growth of both species was decreased more by soil salinity than was grain yield. Both species were less salt tolerant at germination than they were after the three-leaf stage of growth.

Modeling the effects of saline water use in wheat-cultivated lands using the UNSATCHEM model

“…This equation provides the standard values of threshold and slope for yield reduction due to salt stress (Maas and Hoffman 1977) of 6.9 dS m -1 and 5.61 % decrease per 1 dS m -1 increase above the threshold, respectively. Note that the threshold value obtained in our study indicated a slightly higher salt tolerance than reported by Maas and Grattan (1999) (i.e., 6 dS m -1 ) and lower than recorded by Francois et al (1986) (8.6 dS m -1 ). In experiments with different wheat cultivars in an extremely dry region of Iran (the Yazd province), Ranjbar (2005) found that wheat cultivars were less salt tolerant than in temperate regions.…”

Impact of ancestral wheat sodium exclusion genes Nax1 and Nax2 on grain yield of durum wheat on saline soils

“…can attract a significantly higher price on the international market than hexaploid (bread) wheat (Triticum aestivum L.); however, it is poorly adapted to salt-affected soils (Zubaidi et al 1999a). Its yield is more affected by salinity than bread wheat (Francois et al 1986;Maas and Grieve 1990). Durum wheat is less able to exclude Na + (Zubaidi et al 1999b;, a trait associated with salt sensitivity in the Triticeae (Gorham et al 1990;Dvorák et al 1994).…”

A locus for sodium exclusion (Nax1), a trait for salt tolerance, mapped in durum wheat

“…Cultivars of durum wheat are more salt sensitive than bread wheat (Gorham et al 1990;Rawson et al 1988), and may yield less when grown on saline soils (Francois et al 1986;Maas and Grieve 1990). The usual high price of durum wheat on the international market can bring a better return to farmers than bread wheat and other crops, so, breeding new cultivars of durum wheat with improved salt tolerance can allow growers more options in dealing with subsoil salinity.…”