Seed emergence and seedling growth of two varieties of cucurbits as affected by varying concentrations of hormones

Abstract

Despite the economic relevance of Citrullus lanatus (Thunb) and Citrullus colocynthis (Schrad), there is decline in the production of the cucurbits due to poor germination and low growth of the plants. This study investigated effects of varying concentrations of Indole acetic acid (IAA), Gibberellic acid (GA₃), Bryophyllum pinnatum leaf extract (BPLE) and coconut water (CW) on germination and seedling growth (SG) of C. lanatus and C. colocynthis (L.). Seeds of the two cucurbits were pre-soaked for 13 hours in 50, 100, 150, 200 and 250 mg/L of the hormones and sown in Petri dishes. The experiment was a factorial design arranged in completely randomised design in five replicates. Percentage Germination (PG) of seeds of the two cucurbits was influenced by varying concentrations of hormones. Highest PG (99.0%) was observed in the seeds of C. lanatus soaked in 150 mg/L BPLE. The highest germination rate (GR) (11.00) was observed in C. colocynthis seeds treated with 100 mg/l BPLE. Seedling index (1161.76) was significantly higher in C. colocynthis seedlings whose seeds were soaked in 50 mg/l CW, seedling dry weight (1.13 g) in the seedling of same variety whose seeds were soaked in 50 mg/l BPLE while highest plumule length (46.20 cm) was observed in the seedling of the C. colocynthis whose seeds were soaked in 50 mg/L 1AA. The highest seedling vigour (9.62) was observed in the C. lanatus seedlings produced by seeds soaked in 250 mg/l BPLE. Seedling length (18.70) and radicle length (8.30) were highest in the seedings produced by C. lanatus seeds soaked in 50mg/l BPLE. Variations in the concentration of the hormones studied had significant changes in PG, germination rate of seeds and seedling vigour of C. lanatus and C. colocynthis even at the lowest concentration. The concentration of 100 and 150 mg/l of IAA, GA₃ and BPLE produced better effects on the PG and GR of the cucurbit seeds while 50 mg/l of the hormones improved SG of the cucurbits. The concentration of 50-150 mg/l of the hormones is recommended for farming.