Genetic adaptability of durum wheat to salinity level at germination stage

Evaluation of genetic adaptability of durum wheat to different levels of salt was conducted at the Faculty of Sciences, University of Tunis El Manar, Tunis from April to May 2010 to improve salt tolerance during germination stage. For this purpose, two crosses and their progenies (F1, F2, BC1Ps and BC1Pr) were used based on shoot length at different salinity levels (0, 50, 75, 100, 150 and 200 mmol/L). Significant differences for salt tolerance between means of generations were observed in all the treatments. Separate generation means analysis indicated that inheritance of resistance to salt at germination stage was dependent upon the level of salinity. With low salinity level (50 and 75 mmol/L), only additive and dominance effects were implicated in the genetic control of this trait. For moderate salinity level (100 and 150 mmol/L) in the two crosses, genetic interactions were solicited and the di-genic epistatic model was sufficient to explain variation in generation means. However, for the 200 mmol/L treatment, none of these models explained the variations in generation means and probably, higher order interactions or genes linkage were solicited. The estimated values of narrow-sense heritability were dependent on the cross and the salinity level and ranged between 29 and 90%. The results of this study indicated that selection in specific environments is useful for enhancing resistance to salt, but it may not be effective in providing resistance across a wide range of environments.