In the face of climate change, wheat farmers are increasingly grappling with the dual challenges of drought and heat stress, which can significantly reduce yields. However, a recent study published in ‘Frontiers in Plant Science’ offers a glimmer of hope. Researchers, led by Sukumar Taria from the Division of Plant Physiology at the Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute in New Delhi, have identified key genetic regions that could help wheat plants maintain their green color and mobilize stem reserves more efficiently under stress conditions. This could be a game-changer for wheat breeding programs aimed at improving yield stability in harsh climates.
The study focused on two crucial physiological traits: stay-green (SG) and stem reserve mobilization (SRM). Stay-green refers to the plant’s ability to maintain its green color and photosynthetic activity under stress, while SRM involves the plant’s capacity to remobilize stored nutrients from the stem to the grain during grain filling. Both traits are vital for sustaining grain production under adverse conditions.
Taria and his team conducted a pot experiment using contrasting recombinant inbred lines derived from the parental lines HD3086 and HI1500. They subjected these lines to normal, drought, heat, and combined stress conditions to validate the quantitative trait loci (QTLs) associated with SG and SRM. The results were striking. Superior lines, such as HDHI113 and HDHI87, exhibited higher expression of SG-related genes in the flag leaf under stress, maintaining higher chlorophyll content and net photosynthetic rates. “These lines showed remarkable resilience, with HDHI113 and HDHI87 recording chlorophyll a contents of 7.08 and 6.62 mg/gDW, respectively, and net photosynthetic rates of 17.18 and 16.48 µmol CO2/m2/s under combined stress,” Taria noted.
Moreover, these superior lines also demonstrated higher expression of SRM-linked genes in the peduncle under drought stress, indicating that drought conditions enhance SRM in wheat. This dual advantage of maintaining green color and efficiently remobilizing stem reserves could be a significant breakthrough for wheat breeding programs.
The implications of this research are profound. By identifying and validating these QTLs, breeders can now use marker-assisted selection to develop wheat varieties that are more resilient to combined stress conditions. This could lead to more stable yields, even in the face of climate change, and potentially reduce the need for costly and environmentally damaging interventions.
As Taria puts it, “The identified QTLs can be transferred to developed wheat varieties through efficient breeding strategies for yield improvement in harsh climate conditions.” This research not only advances our understanding of wheat physiology but also paves the way for more robust and sustainable wheat production systems. With climate change posing an ever-growing threat to global food security, such advancements are not just scientific achievements but also crucial steps towards ensuring a food-secure future.