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University of Jordan (2021)

Evaluation of near isogenic durum wheat lines differing in the NAM-B1 gene under drought stress

Mbideen, Farah Osama,

Titre : Evaluation of near isogenic durum wheat lines differing in the NAM-B1 gene under drought stress

Auteur : Mbideen, Farah Osama,

Université de soutenance : University of Jordan.

Grade : M.Sc in Horticulture and Crop Science 2021

Wheat is one of the most important cultivated crops in the world. Durum wheat (Triticum turgidum spp. durum) is considered an important crop in the Mediterranean region and is commonly used for different purposes. Climate change is the main constrain which is expected to limit durum wheat cultivation in this region. Therefore, there is an urgent need to develop new climate-smart cultivars that can withstand and tolerate different abiotic stresses such as drought and heat. Utilizing of stress-responsive genes and natural variants by incorporating them into wheat breeding programs are expected to enhance tolerance against multiple abiotic stresses including water deficit. Accordingly, the main objective of this study was to assess the role of NAM-B1, a wheat Transcription Factor associated with senescence, in drought tolerance. For this purpose, selected three set of durum wheat near isogeneic lines (NILs) along with a check genotype differing in the NAM-B1 gene were subjected to three water regimes (well-watered, moderate and water stress) under greenhouse conditions and were evaluated for their agronomic performance and physiological responses under stress. Water deficit stress had negative effects on different agronomic and physiological parameters on all tested genotypes. NILs flower and mature earlier than the check and had higher Plant height (PH), Tiller number (TN), Spike number (SN) and Spike length (SL). On the other hand, the check plants had higher Grain per spike (GpS), Thousand kernel weight (TKW) and Total main spike grains weight (TMSGW) when compared with NILs carrying functional allele of NAM-B1 and in particular under severe water deficit treatment. For physiological traits, the mean values of Transpiration (E), Stomatal conductance (Gs), Relative water content (RWC) and Chlorophyll content were significantly reduced under water deficit, while Stomatal resistance (SR) and Photosynthesis rate (Pn) were significantly increased with no clear significant differences between tested genotypes. No significant differences were observed between the three NILs in response to water deficit under greenhouse conditions for many physiological and agronomical traits especially those associated with yield. Therefore, the role of NAM-B1 gene under drought conditions in wheat plants should be further tested and correlated with early maturity phenotypes under water deficit in the field in order to investigate its potential role in drought escape mechanisms in dry areas


Page publiée le 21 mai 2022