Effect Of Climate Changes on Relationship Among Sowing Dates and Rust Resistance on Wheat Yield

This study was carried out at the Experimental Farm of El-Gemmeiza Agricultural Research Station, Agricultural Research Center (ARC), El-Gharbia Governorate, Egypt, during the 2021/2022 and 2022/2023 growing seasons. The objective was to investigate the effect of various sowing dates (05th November, 30th November and 25th December) against rusts and their impact on potential yield of ten bread wheat genotypes. The experiment was laid out in a randomized complete block design (RCBD) with three replicates for every sowing date as a separate experiment. Data were recorded on phonological traits, yield attributes, grain yield, and rust severity. Early and optimum sowing dates (5th –30th November) enhanced yield components such as no. of spikes/m², no. of grains/spikes, and 1000-kernel weight, leading to higher grain yield compared to late sowing (25th December). Late sowing was associated with unfavorable climatic conditions, shorter growth duration, higher rust severity, and a considerable reduction in yield. Significant differences among genotypes were also observed. The cultivars Misr 4 and Sakha 95 consistently outperformed the others, achieving the highest grain yield due to their better adaptability and rust resistance, while Gemmeiza 12 and Misr 2 recorded the lowest yields. Moreover, the interaction between sowing dates and genotypes was significant, indicating that genotype performance depended on environmental conditions. In conclusion, sowing in early November using high-yielding and rust-resistant cultivars such as Misr 4 and Sakha 95 is recommended to sustain wheat productivity and mitigate the negative impacts of climatic changes in Egypt.