EFFECT OF PLANTING DATES ON THE GROWTH OF GLADIOLUS CORMS IN PESHAWAR

Abstract

The stem of gladiolus is herbaceous and the leaves are narrowly linear, flattened at the sides and sheathing at the base. The flowers are bisexual, actinomorphic, perianth petaloid, have 3 stamens and the ovary is completely inferior (Hutchinson, 1959). The propagating material of gladiolus is called which is a food-storing underground stem. The corm has the ability to maintain the plant while dormant until growth resumes after the spring rains begin. Upon plantation, gladiolus corm produces on its top a new daughter corm each year and itself shrivels and dies. The buds development occurs on the upper surface of the daughter corm from which the new plant grows the following year. The bases of old leaves are thin and dry, which cover the corm. These papery leaves are called husks. The husks overlap each other and meet to form a point at the top. While the new daughter corm is forming on the top of old one, small new corms called cormels or cormlets are produced from the base. These corms and cormels are the chief means of gladiolus propagation. Cormels are usually graded in to three sizes: large more than 1.0 cm diameter, medium 0.5 cm to less than 1.0 cm, and small less than 0.5 cm. Cormels are treated before storage with hot water solution to eradicate latent fungi, insect and nematodes (Larson, 1992). The cormel formation starts with the initiation of the flower spikes. When the spikes attain full bloom, cormels are produced. After flowering, when the photosynthates are directed downwards, the cormels continue to increase in size (Hartmann et al. 1981).