A field experiment was carried out at the Experimental Farm of Agronomy Dept., Assiut University, during the 2021/2022 and 2022/2023 seasons. The work aimed to investigate the effect of three phosphate fertilizer applied dates (before the first P₁, second P₂, and third irrigation P₃) and four gibberellic acid levels (0, 50 G₁, 150 G₂, and 250 G₃ ppm) on three fab bean cultivars (Misr1, Sakha 4 and Giza 843). The experiment was laid out in randomized complete block design (RCBD) using a strip plot within a split plot with three replicates. The plot area was 9 m².
The results revealed that maximum seed yield in addition to yield attributes were produced from plants receiving 250 or 150ppm gibberellic acid with third and second phosphorus application in both seasons. Giza 843 cultivar was significantly higher seed index, biological and seed yield in both seasons. The maximum Pod number/plant and seeds number/pod in the 1^st season were recorded by 250ppm gibberellic acid concentration under the first and second phosphorus application dates (G₃×P₁ and G₃×P ₂) in the 2^nd season. Moreover, the maximum seeds and biological yield were recorded by 250ppm gibberellic acid concentration under the third phosphorus application date (G₃×P₃) in both seasons. Furthermore, the tallest plants, maximum seed index and biological yield were recorded by Giza 843 cultivar under the second and third phosphorus application dates (V₃×P₂ and V₃×P₃) in both seasons. Maximum pod number/plant and seed yield were recorded by Misr1 cultivar under the first and third phosphorus application dates (V₁×P₁ and V₁×P₃) in both seasons.