| Results and Discussion The germination test indicates significant differences among cultivars in germination percentage due to some unknown factors but not salinity (Table 2). These results imply that wheat and triticale seeds were tolerant to high salinity (EC 11 mmhos/cm) during germination. BHUMBLA & SINGH (1965) however, noted that germination percentage of wheat at EC 12 and 16 mmhos/cm delcined by 25% and 80%, respectively. Interactions between soil salinity and available soil water induced significant effects on dry matter content (Fig. 1), grain yield, grain number, and 100-grain weight (Tables 2 and 3). The stress conditions caused by high soil salinity and limited soil moisture progressively decreased the dry matter content of the wheat plant. In this case, the triticale line was the most tolerant to the highest salinity level though Super-X was more tolerant up to EC 8.5 mmhos/cm (Fig. 2). Interactions of cultivar x soil moisture and cultivar x soil salinity were significant for grain yield, grain number and 100-grain weight (Fig. 3). This indicated that the response of these parameters to stress conditions were cultivar dependent. On the basis of grain yield, the Florence line was found to be the most productive cultivar under stress condition caused by limited moisture and increased soil salinity followed by Arz and Super X, Table 3. When the relative yields (% of the control) were considered, the triticale line was found to be the most tolerant cultivar to stress conditions (yielding 62% of control), followed by Arz (59%), Florence (56%) and Super X (55%) (Table 4). The triticale line, however, showed a marked reduction in number of spikes and number of spikelets but less reduction in 100-grain weight compared to other cultivars which remained unchanged in the number of spikes. The differential response of grain yield and related characters in relation to soil stress conditions underline the genetic variability among the wheat and triticale cultivars thus warrant selection. Reduction in soil moisture from 100% to 20% of the available water caused a remarkable loss in grain yield mounted to 56% of the control (Table 4). The number of spikes was reduced upon the decrease of available water from 100% to 50% only while spikelets and grain numbers were affected with each decrease in soil available water. Since the grain test weight remained independent from the change in soil available water, the loss in grain yield could be attributed to cumulative effects caused by reduction in spikes, spikelets and grain numbers, respectively. |
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