Abstract: Use of chemical fertilizers and pesticides in rice cultivation has incurred many environmental and health problems in Sri Lanka. Therefore, there is renewed interest in cultivating traditional rice varieties as they are more amenable to organic farming practices. However, as the yield of these varieties is comparatively low, strategies to enhance their performance should be investigated. As endophytes of plants are reported to promote growth and yield of a number of crop varieties, this study was aimed at studying the endophytic fungal assemblage present in the traditional rice variety Kuruluthuda with a view to evaluate their capacity to enhance plant growth and yield. Twenty seven endophytic fungal species were isolated from different parts of Kuruluthuda rice plants collected from a paddy field cultivated using organic fertilizers in the Gampaha district, Sri Lanka. Two frequently isolated endophytic fungal spp. i.e. Acremonium and Arthrobotrys (frequencies of isolation 60% and 38.6% respectively) were introduced separately and in combination torice seedlings using spore suspension and plate methods to determine their effect on growth and yield under green house and field conditions. All endophyte inoculated plants showed a significant difference (P ≤ 0.05) in plant growth (height, fresh weight and dry weight), number of tillers and yield when compared withnon-inoculated plant sunder both green house and field conditions. The effect of Acremonium and Arthrobotrys when introduced in combination showed a significant difference (P ≤ 0.05) in the fresh weight, dry weight, tiller number and yield (weight of seeds harvested) when compared to their individual effects under field conditions which indicates that the two endophytes in combination can be used as a better inoculum to improve biomass and yield of the plants of rice variety tested. This is the first report of the endophytic mycoflora of the rice variety Kuruluthuda and their potential use for growth promotion and yield enhancement.
Fig.: Endophytic fungal structures in Kuruluthuda roots