Research Projects

Wheat production is increasingly threatened by salinity and high night temperatures (HNT), which impair seedling vigor and reduce yield, particularly during reproductive stages. Minimum temperatures are rising faster than maximums, especially in the rabi season (0.28°C/decade) (Rao et al., 2014; Wang et al., 2017; Fu et al., 2023). Climate projections indicate a 2.3% decline in wheat yield in Southeast Asia by 2030 due to HNT (IPCC, 2022), while the effects of salinity remain variable and region-specific. Salinity and high night temperatures (HNT) cause overlapping physiological disruptions—osmotic imbalance, oxidative stress, and impaired photosynthesis—leading to reduced yield. Understanding their combined impact on early crop establishment is crucial, as it influences final yield. While most studies focus on reproductive-stage heat tolerance, seedling-stage screening is vital for uniform establishment and efficient seed use (Mason et al., 2011; Mondal et al., 2014; Tadesse et al., 2015). In a pioneering effort, the mentor’s lab identified 41 HNT-tolerant (~4.9°C above ambient) wheat genotypes (≤10% shoot dry weight reduction) from 290 lines, showing a strong link with early vigor. Genome-wide association studies (GWAS) revealed 22 SNPs, some shared with salinity tolerance (Hussain et al., 2018), indicating a possible genetic convergence of the two stress responses at early growth stages. This association warrants exploration at crop establishment and reproductive stage of the crop. Raffinose family oligosaccharides (RFOs) aid in salinity, heat, and drought tolerance via osmoprotection, ROS scavenging, and sugar transport (Peters et al., 2007; Elsayed et al., 2014). Prior work links raffinose accumulation to salt tolerance in sugar beet and HNT tolerance in rice and wheat (Naguib et al., 2021; Mukherjee et al., 2023; Sharma et al., 2025). Knowledge gap: Although individual effects of HNT and salinity on wheat growth and yield have been studied, their combined impact, especially at the physiological and genetic levels, remains underexplored. Further, the role of raffinose as a potential common mediator linking tolerance to both the experimental stresses during early establishment in wheat is not known. Hypothesis: Wheat tolerance to HNT and salinity stresses is genetically interconnected and mediated by shared physiological mechanisms, such as osmotic balance and ROS regulation, with raffinose mediating the protective responses. Leads from previous work: The mentee’s earlier research showed that glucose alleviated 50 mM NaCl stress in mustard (Sami & Hayat, 2018; Sami et al., 2021). The mentor’s lab reported elevated raffinose and glucose in tolerant sugar beet, rice, and wheat genotypes under the salinity and the HNT stress (Naguib et al., 2021; Sharma et al., 2025; Mukherjee et al., 2023). These findings support testing exogenous raffinose in contrasting wheat genotypes under combined HNT and salinity stress.