Responses of above and below-ground traits of wheat wild relative (Aegilops tauschii) and bread wheat (Triticum aestivum L.) to imposed moisture stress

The narrow genetic variation of bread wheat is one of the limitations to improve it for drought-tolerance. The research carried out to study the responses of different genotypes and traits to imposed moisture stress. The plant material comprised of 10 Aegilops tauschii accessions as well as a tolerant (BW2) and a susceptible (BW1) bread wheat cultivar. To assess the root and shoot-traits, two separate pot experiments were conducted, under normal and moisture stress conditions during 2013–14 and 2014–15 years. The majority of the traits were significantly affected by the genotypes (G), water treatments (WT), and G×WT interaction. The results revealed a high inter genus diversity for the all traits, except tillers number per plants. A19 accession was less affected by the imposed moisture stress, while A14 and A16 were the most affected ones. In addition, BW2 cultivar was more tolerant, with a greater yield, than BW1. Water use efficiency and seed weight per main spike were the most effective traits to improve grain yield. A high amount of water use efficiency, plant harvest index, spikelet number per spike, seed number per main spike, seed number per plant, biological yield per plant, and RWC, and a low amount of phenological traits (except grain filling period), excised leaf water retention, and root to shoot dry weight ratio were suggested for improvement of grain yield. Harvest index and biomass were two main-components of grain yield in the favorite (BW2 and A19) genotypes. A19 and BW2 may have value for breeding wheat better adapted to moisture stress conditions.