EffEctivE sElEction critEria for assEssing drought strEss tolErancE in durum whEat (TriTicum durum dEsf.)

Drought is a wide-spread problem seriously influencing durum wheat (Triticum durum Desf.) production and quality, but development of resistant cultivars is hampered by the lack of effective selection criteria. The objective of this study was to evaluate the ability of several selection indices to identify drought resistance cultivars under a variety of environmental conditions. Twenty four durum wheat lines and cultivars were evaluated under both moisture stress (E1) and non-stress (E2) field environments using a randomized complete block design for each environment. Seven drought tolerance indices including stress susceptibility index, stress tolerance index, tolerance, yield index, yield stability index, mean productivity and geometric mean productivity were used. The indices were adjusted based on grain yield under drought and normal conditions. The significant and positive correlation of Yp and MP, GMP and STI showed that these indices were more effective in identifying high yielding cultivars under different moisture conditions. The results of calculated gain from indirect selection from moisture stress environment would improve yield in moisture stress environment better than selection from non moisture stress environment. Wheat breeders should, therefore, take into account the stress severity of the environment in choosing an index.