Estimation of genetic parameters and heritability of photosynthetic-related traits in Aegilops tauschii accessions under water deficit stress

Wild relatives of wheat are one of the important genetic resources for using in breeding programs. In this study, a set of diploid wild wheat possessing D genome (Aegilops tauschii Coss.) were evaluated for some photosynthetic-related traits under two control and water deficit stress conditions. Under stress condition, Analysis of variance showed significant differences among accessions for chlorophyll a, chlorophyll b, carotenoid content, photosynthesis capacity, maximum quantum yield of PSII and seedling fresh and dry biomasses. Water deficit stress reduced all traits and the highest reduction was recorded for seedling fresh and dry biomasses as well as chlorophyll b, respectively. Furthermore, genetic parameters were affected by water deficit stress so that stress condition increased all parameters compared with the control condition. Under stress condition, the genetic gain showed an increasing pattern and it ranged from 3.46 to 54.04. The highest genetic gain value was obtained for the seedling fresh weight (54.04%), chlorophyll b (29.93%) and photosynthesis capacity (26.44%), respectively. In both control and stress conditions, the highest environmental, phenotypic and genotypic coefficient of variances (ECV, PCV and GCV, respectively) were recorded for the last mentioned traits. In general, regarding the high level of genetic diversity in Ae. tauschii species, as well as a high rate of heritability for measured traits, future comprehensive evaluation on this germplasm, is recommended.