OPTIMIZING SEEDING RATES FOR MAXIMIZING GRAIN YIELD AND PROFITABILITY OF WHEAT CULTIVARS IN NEW VALLEY

Optimizing seeding rates for specific wheat cultivars are critical for maximizing grain yield and profitability, particularly in new agricultural lands. A field experiment was conducted during 2022/2023 and 2023/2024 seasons at Al Farafra, New Valley, Egypt to evaluate the performance of six wheat cultivars-four bread wheat (Sakha 95, Misr 4, Misr 2 and Giza 171) and two durum wheat cultivars (Bani Suef 5 and Bani Suef 7) differing in 1000-kernel weight- under five seeding rates (250, 325, 400, 475, and 550 grains m-²). The experiment was laid out in a split-plot design with three replications, Where cultivars were assigned to the main plots and seeding rates to sub-plots. Response curve approach was employed to assess yield trends and determine economically optimal seeding rates. Results revealed significant effects of cultivar seeding rate and their interaction on earliness traits, plant height, yield, and yield components. Misr 2 consistently recorded the highest grain yield (26.1 ardab fed⁻¹) across both seasons followed by Bani Suef 7 in the first season. Intermediate yields were recorded for Misr 4 and Sakha 95, While Giza 171 and Bani Suef 5 had the lowest performance. Increasing seeding rates generally reduced days to heading and maturity, number of grains per spike, and 1000-kernel weight, While increasing plant height and number of spikes m⁻². The highest yields were achieved at 475 grains m⁻² in the first season and 400 grains m⁻² in the second. The average optimal seeding rates (kg fed⁻¹) across both seasons were: Misr 2 (73.10), Sakha 95 (83.29), Misr 4 (85.63), Bani Suef 7 (90.80), Bani Suef 5 (103.02), and Giza 171 (107.87). Economic analysis using a quadratic response model indicated that the most profitable seeding rate was approximately 73 kg fed⁻¹, with maximum yield reaching 26.6 ardab fed⁻¹ and net profit exceeding 56,859.23 LE fed⁻¹. The findings emphasize the need to consider 1000-kernel weight when determining optimal seeding rates, as cultivars with larger and heavier kernels often require higher seed rates to achieve maximum yield potential.