Effects of irrigation frequencies on aerial agro-morphological parameters of Dioscorea hispida Dennst. (Dioscoreaceae).

Effects of irrigation were studied in Dioscorea hispida Dennst. (Ubi gadong) in Terengganu, Peninsular Malaysia, by quantifying selected agro-morphological parameters under various irrigation frequencies. The automatic timer attached to the power supply was used as a controller, while the pump was controlled by this timer in accordance to the frequencies which had been setup as: 1) watering at everyday in a week (T2); 2) watering at two day interval in a week (T3); 3) watering at five day interval in a week (T4); and 4) watering at six day interval in a week (T5). The control treatment for the frequency of water supplied was 5) watering at one day interval (T1). The ANOVA statistical test between collection time data on effect of irrigation to treatment showed significant differences at D4 (final growth period) for plant height, petiole formation, number of leaf and number of branch; where the P-values were recorded at 0.001, 0.004, 0.005 and 0.010, respectively. All parameters showed an increasing pattern from D0 until D4. The results also indicated that T2 had the highest of all agro-morphological growth parameters, except the number of branch, at mean ± standard error of 389.80 ± 22.47 cm, 46.40 ± 7.80, 139.20 ± 23.40,0.76 ± 0.07 cm and 3.80 ± 1.32 for plant height, petiole formation, number of leaf, stem thickness and number of stem, respectively. T2 showed no significant difference between T1 and T3 for all parameters. Therefore, it was revealed that D. hispida can grow well when grown using irrigation frequency of not more than three day watering interval. This technology will enable water and labor cost saving in commercialized propagation of this plant.