Effect of sowing depth on growth performance of selected members of the family Cucurbitaceae

A field experiment was conducted to investigate the agronomical responses of Citrullus colocynthis, Luffa cylindrica and Citrullus lanatus to varying sowing depths (2, 4, 6 and 8 cm). Agronomic parameters such as number of leaves, fruit weight, leaf area, vine length and width were taken. The Relative Growth Rate (RGR), Net Assimilation Rate (NAR) and Leaf Area Ratio (LAR) for each cucurbit were determined from the data on leaf area and dry weight of seedling. The number of leaves and vines, vine length and width of cucurbits at 2 cm soil depth increased significantly compared with those at 8 cm. However, agronomical responses of the cucurbits at 2 cm soil depth were similar to those at 4 cm. At 2 cm sowing depth, the fruit weight of C. lanatus, L. cylindrica and C. colocynthis increased by 47%, 35% and 20%, respectively compared with those at 8 cm. Also, the RGR, NAR and LAR of C. colocynthis, L. cylindrica and C. lanatus at 2 cm sowing depth increased significantly (p<0.05) compared with those at 8 cm. The findings showed that the vegetative and physiological characteristics of C. colocynthis, L. cylindrica and C. lanatus increased when sown at depths of 2 - 4 cm.