The effect of pre-soaking common bean (Phaseolus vulgaris) seeds in gibberellic acid solution on germination and seedling growth

Abstract

Poor seed germination and early seedling growth often limit common bean production. Pre-treatment with plant hormones, such as gibberellic acid (GA₃), can improve germination and seedling vigour in many plants. However, its effects on common bean seeds are not well understood. This study evaluated GA₃’s potential to promote germination and seedling growth in common beans. Laboratory germination tests and greenhouse trials were conducted using two varieties, Gloria and Nua45. Seed from each variety was divided into two groups and the other group was soaked in 60 ml/L GA₃ solution for 5 min and the other group was left untreated and used as a control. Treatments were arranged in a completely randomized design with three technical and two biological replicates. Data on germination percentage were collected every 24 hours for 120 h, along with measurements of rootlet length, seedling vigour indices, root length, shoot length, and dry weight. Results indicated that GA₃-treated Nua45 seeds had significantly higher germination percentages than untreated seeds after 48, 72, and 96 h, while treated Gloria seeds showed lower germination than untreated seeds within the same time frames. By 120 h, both treated and untreated seeds of both varieties reached a minimum of 90% germination. Nua45 seeds treated with GA₃ showed significantly greater rootlet length (5.29 cm) than untreated seeds (4.12 cm), while Gloria seeds showed no significant difference in rootlet length between treated (2.49 cm) and untreated seeds (2.86 cm). For Nua45, GA₃-treated seedlings had higher shoot length (46.7 cm), dry weight (4.10 g), and seedling vigour index II (3.7) than untreated seedlings (28.5 cm, 2.34 g, and 2.25, respectively). In contrast, untreated Gloria seedlings had greater root length (35.1 cm) than treated seedlings (14.4 cm), with no shoot length difference. These findings suggest that pre-soaking Nua45 seeds in GA₃ solution enhances germination and growth, while pre-soaking Gloria seeds reduces them. These findings suggest a hormone-genotype interaction effect warranting further study.