Determination of drought stres tolerance of bread wheat hybrids and parents in a rapid breeding system

Plant breeders are making intensive efforts to develop new wheat varieties that are tolerant to drought. In the face of the rapidly progressing climate crisis, it is necessary to shorten plant breeding cycles. This study aimed to evaluate the drought stress tolerance of bread wheat hybrids and parent lines using a rapid breeding system. Wheat genotypes were tested under both well-watered and drought stress conditions within the rapid breeding system. In this system, plants were exposed to a photoperiod of 22 hours light and 2 hours darkness. Plants grown in pots were nourished for 20 days after emergence with a compound fertilizer containing optimal macro and micro elements. Until the end of the harvest period, traits such as heading time, plant height, chlorophyll content, number of spikes, spike length, number of grains per spike, grain weight, biological yield, grain yield, harvest index, protein, gluten, and oil content were determined. Significant differences were found between well-watered and drought stress treatments in all investigated traits. Heading time was determined to be 52.1 days on average, while grain yield was found to be 10.5 g/pot under well-watered conditions and 6.8 g/pot under drought conditions. A significant genotype × irrigation interaction was observed for chlorophyll content, number of grains per spike, grain weight, biological yield, and harvest index. Additionally, components of yield such as the number of grains per spike (avg. 27.3) and grain weight showed a decrease under drought stress. However, some hybrid lines (e.g., M6 and M9) stood out under both drought and well-watered conditions with high chlorophyll content, early heading time (48–50 days), and high grain yield (8.5–10.0 g/pot). This study demonstrated that the drought stress tolerance of bread wheat hybrid combinations can be evaluated using a rapid breeding system. Achieving up to 5 generations per year may significantly shorten the development time of new varieties compared to traditional methods. Moreover, this system enables the rapid identification of stress-tolerant lines and can strategically contribute to modern wheat breeding programs. Keywords: Wheat, Speed Breeding, Drought Stress, Selection, Yield, Quality