| Performance of wheat and triticale cultivars subjected
to soil salinity and soil moisture stress conditions. Hassan I. SAYED and Abdo S. MASHHADY College of Agriculture, King Saud University, Riyadh, Saudi Arabia Farming in arid regions is completely dependent on irrigation water which normally carries high contents of salts in contrast to rain water. Although some of the ions which contribute to soil salinity may be indigenous in the soil, many are brought to soils in the irrigation waters. Poor drainage and high evaporation eventually accelerate salt accumulation. Varietal response to salinity can play a key role in maintaining farming in arid regions using low quality irrigation waters. In the Central Region of Saudi Arabia, most farming soils are highly calcareous and considered saline or subjected to high salinity upon irrigation from sources with high content of salts. Therefore, it was found important to study the tolerance of some selected wheat and triticale cultivars to stress conditions induced by high soil salinity and limited soil moisture content. Materials and Methods The experiment was carried out in greenhouse at the college of Agriculture, King Saud University. A representative soils sample was collected from the University Experimental Farm. A routine analysis was carried out in the laboratory and the main soil characteristics are shown in Table 1. Accordingly, the soil was considered non-saline (EC 3.7 mmhos), highly calcareous (37% CaCO3) and sandy loam in texture. Four levels of soil salinity were achieved at 3.7 (control), 6.0, 8.5 and 11.0 mmhos/cm. The salinity Ievels were attained by adding a solution containing NaCl, CaCl2, MgCl2 in amounts equivalent to 3:2:1 ratio, respectively. The moisture content in each level was kept more or less constant at three levels: 100%, 50% and 20% of available water. These levels were achieved by weighing the pots daily and the loss of water was compensated by adding enough water to reach the required moisture level of the soil. Three wheat (Triticum aestivum, L.) and one triticale (Triticosecale Wittmack) cultivars were used. These were: Florence aurore, Super X, Arz and triticale line Armadillo "S" x 308-3N'. A germination test was carried out in the laboratory. Twenty germination dishes each contained 20 seeds were prepared from each cultivar. They were arranged in five groups, each of four replications. These groups were allowed to germinate under saline solutions of; distilled water, 3.7, 6.0, 8.5 and 11.0 mmhos/cm. The dishes were kept in the dark at room temperature. Number of germinating seeds were counted twice after five and nine days. Only normal seedlings were counted. The four lines were seeded in pots on December 3, 1978. After germinations, the pots were thinned to five plants in each. The 12 treatments four salinity and three moisture levels, were arranged in a factorial experiment within each cultivar (four replications). A total of 192 pots occurred in the experiment. Each pot received a nutrient solution containing 160 ppm N , 20 ppm P and 20 ppm K. The solution was divided into equal portions, then added after 15 and 56 days from planting. Micornutrients were all added at once in a concentration similar to Hoagland solution. The pots remained in the greenhouse throughout the whole experiment. Fifty-six days after planting, before anthesis, one of the four replicates was harvested for dry matter content. The remaining three replications were harvested at maturity and data were recorded on the following parameters; spikes per pot, spickelets per pot, grain number per pot, grain yield per pot (g), and 100-grain weight. A routine analysis of variance was applied to all data and means were tested by Duncan's multiple range test. |
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