Standardisation of propagation and stage of harvest in adakodien

Abstract

Investigations on standardization of propagation and stage of harvest in adakodien (Holostemma annulare k. Schum.) were carried out at the Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara during 1992-94. The trial was laid out in a factorial RBD with 3 replications. The treatments comprised of fifteen combinations of five planting materials (seedlings, 2 noded vine cuttings, 3 noded vine cuttings, root stumps 10 cm and main root cuttings 5 cm) and three stage of harvest (9, 12 and 18 months after planting). Seedlings were rated as the best planting material realizing maximum yield potential of fresh and dried roots (3.49 t ha-1 and 1.19t ha-1 respectively). Root characters contributing to yield, driage and harvest index and biometric characters related with yield such as internodal length, diameter of the vine and number of branches were highest for seedlings. The soluble carbohydrate content was also maximum for seedlings. Rating of the planting material under field condition followed the same trend as in the nursery. The preference for the five planting material in the decreasing order were seedling, root stump 10 cm, 3 noded vine cutting, 2 noded vine cutting and main root cuttings 5 cm. The presence of large number of seeds in a fruit coupled with high germination per cent and field establishment and the high yielding nature of seedlings make this a commercially acceptable planting material. Harvesting the roots 18 months after planting was found to be most beneficial for achieving maximum yield (4.14 t ha-1 and 1.56 t ha-1 of fresh and dry roots respectively). Biometric characters related to yield such as internodal length, diameter of the vine and number of branches and all the root characters, driage and harvest index were maximum at this stage. Total aminoacid and soluble carbohydrate content showed a progressive increase with advance in age and highest content was recorded at 18 months after planting. Six free aminoacids were isolated from the roots and they were identified as alanine, aspartic acid, glycine, valine, serine and threonine. Seedlings harvested after 18 months was the most desirable treatment combination for realizing maximum yield of roots and chemical components. Characters such as internodal length, diameter of vine, number of branches and root volume could be taken as selections indices for high root yield. The benefit cost analysis suggest that adakodien is a profitable crop which can be groomed as a commercial crop for Kerala.