Effect of Pre-Planting Treatments of Corms with Plant Growth Regulators on Growth, Flowering and Planting Material Production of Gladiolus (Gladiolus grandiflorus L.)

Abstract

The experiment was conducted to study the influence of pre-planting corm treatments with plant growth regulators (PGRs) on growth, flowering, and planting material production in gladiolus (Gladiolus grandiflorus L.) cv. ‘Candyman’. The research was carried out at the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat (26.75°N, 94.22°E), Assam, during 2024-25 using a Randomized Block Design (RBD) with seven treatments and three replications. Treatments consisted of GA₃ at 100, 150, and 200 ppm, Ethrel at 150, 200, and 250 ppm, and a control (distilled water). Uniform corms (4.5–5.0 cm in diameter) were soaked in respective solutions for 24 hours before planting. Significant variations were observed among treatments for all growth and flowering parameters. Corms treated with Ethrel 250 ppm (T₆) recorded the highest spike length (91.80 cm), maximum floret diameter (12.13 cm), and earliest spike emergence (75.3 days), while GA₃ 200 ppm (T₃) promoted the greatest plant height (90.17 cm) and number of leaves per plant. Ethrel 250 ppm also produced the highest corm weight (137.03 g), corm diameter (8.07 cm), and number of cormels per plant (13.39), indicating enhanced propagation efficiency. The untreated control exhibited the poorest performance for all parameters. The results indicate that pre-planting soaking of corms in Ethrel 250 ppm effectively enhances both floral and planting material attributes in gladiolus, while GA₃ 200 ppm promotes vigorous vegetative growth. The use of suitable PGR concentrations before planting thus offers a simple and practical approach to improve quality flower production and propagation efficiency in gladiolus.