Fertilizer Response of some Sri Lankan Traditional Rice Cultivars during Vegetative Growth Phase

Traditional rice cultivars in Sri Lanka conserve different abiotic and biotic tolerant traits but the yield of traditional rice cultivars is not as much of improved cultivars. Abiotic stress tolerance of some traditional rice cultivars were evaluated in previous studies at Faculty of Agriculture, Mapalana, Sri Lanka and this study attempted to understand the possibility of enhancing the yield and yield components of traditional rice cultivars by altering the fertilizer dose. A field experiment was carried out from October 2011 to April 2012 at the Faculty of Agriculture, Mapalana. Traditional rice cultivars are considered to be weaker in response to fertilizer. Four different fertilizer levels namely no fertilizer, half of the recommended dose, recommended dose and twice of the recommended dose were evaluated with forty Sri Lankan traditional rice cultivars to understand the response of them on different agronomic parameters. Germinated seeds were planted in rows with 15 cm X 20 cm spacing. Twenty plants were managed for each line and three lines were maintained for one replicate of cultivar. Experiment was conducted with four replicates. Effect of fertilizer on the plant height, number of tillers/plant and number of leaves/plant were measured at three weeks after transplanting during the vegetative phase of cultivars. These parameters were significantly differed with the fertilizer doses and with the individual cultivars. Average plant height was ranged from 37.8 cm to 115.8 cm. The highest plant height was obtained by the cultivar Herath Banda (115.8 cm) at the half recommended dose while the lowest plant height was recorded by the cultivar Palasithari 601 (37.8 cm) at no fertilizer dose. Highest number of tillers per plant (7.3) and the highest number of leaves per plant (28.8) were obtained by the cultivar Dena wee at the twice recommended dose and also the lowest tiller number (1.55) and the lowest number of leaves/plant (6.2) was recorded by the cultivar Palasithari 601 at the twice recommended dose. Among tested traditional rice cultivars, cultivar Herath Banda recorded the highest plant height at all four fertilizer levels (no fertilizer (111.6 cm), half recommended dose (115.8 cm), recommended dose (103.6 cm), and twice recommended dose (105.9 cm). Dena wee recorded the highest number of tillers at no fertilizer (7.0), recommended dose (5.9) and twice recommended dose (7.3) while Herath Banda recorded the highest number of tillers (5.6) at half recommended dose. Highest number of leaves at no fertilizer dose was recorded by the cultivar Kotathavalu 1 (22.3). Cultivar Herath Banda (22.2) recorded the highest number of leaves at half of the recommended dose while cultivar Dena wee recorded the highest number of leaves/plant at recommended dose (21.1) and twice recommended dose of fertilizer (28.8). Correlation of these parameters and other yield components with the final yield is yet to be computed.