Traditional rice varieties, although low producers of yield, are more amenable to organic farming practices that cause less damage to the environment and human health. Improved growth and reduced disease incidence would produce higher yields, and endophytic fungi have proven to be effective in achieving these ends in wheat. With this in view, endophytic fungal assemblages of two traditional rice varieties of Sri Lanka i.e. Suwandel and Kaluheenati were evaluated for their effect on the growth and disease incidence of rice plants, because the endophytic mycoflora of these two traditional rice varieties and their effects have not been studied before. The most common and the highest occurring endophytes of both rice varieties i.e. Absidia and Cylindrocladium were tested to determine their effect on rice plant growth and the results showed that the plants inoculated with both fungal isolates showed significant increases (p ≤ 0.05) in plant height, fresh weight and dry weight. Twenty two endophytic fungal isolates common to both rice varieties were screened using dual culture assay for their ability to control the mycelial growth of Magnaporthe grisea, the causative agent of rice blast disease. All tested endophytes controlled pathogen growth by coiling the hyphae around the pathogen and forming clamps and loops. However, Absidia and Acremonium showed the highest growth inhibition of the pathogen (100 %) and showed an abundance of the above inhibitory structures. The effect of crude culture filtrates of thirteen endophytic fungi tested using the diffusion plate method indicated antagonistic activity against the rice pathogen. In planta tests were carried out to assess the effect of three endophytic fungi i.e. Acremonium, Absidia and Penicillium on infection by M. grisea. Disease symptoms were observed only on the leaves of the rice plants grown from Penicillium inoculated seedlings and on plants used as controls sprayed with a 1×10 7 spores/mL suspension of the pathogen. Pre-inoculation with Acremonium and Absidia were effective in preventing infection by the blast fungus. No disease symptoms were observed in plants pre-inoculated with endophytes and in plants used as controls sprayed with a 1×10 5 spores/mL suspension of the pathogen. Twenty one endophytic fungi common to both rice varieties were assessed by the culture plate method in this study.

Allium cepa is used as a condiment and reduction of yield due to infectious diseases is a major economical constraint. The present study was aimed at isolation and identification of fungal pathogens associated with damping-off disease of onion in Sri Lanka. Trichoderma spp. present in the soil of the same onion fields were isolated with a view to evaluating them as possible biocontrol agents of damping-off pathogen(s). The diseased seedlings were collected from fifty-five onion fields in Matale and Anuradhapura districts during the yala season. Soil collected from the same onion fields and soil fungi isolated using the Warcup method. Fusarium sp. isolated from diseased seedlings was confirmed to be the causative agent of damping-off disease of big onions by following Koch's postulates. The pathogenic Fusarium sp. was identified as Fusarium solani based on the similarity matches of the Internal Transcribed Spacer region using Basic Local Alignment Search Tool. Two Trichoderma spp. showing significantly high (p ≤0.05) reduction of growth of F. solani in dual culture assay, higher sporulation capacity and growth rates were identified as T. asperellum (Tr.3) and T. virens (Tr.1). Polymerase Chain Reaction (PCR) using two primer pairs i.e. ITS 1 and ITS 4, FR 1 and NS 1 were used to characterize the seven Trichoderma spp. while ITS 1 and ITS 4 were used to characterize Fusarium spp. Although a lesser degree of polymorphism was detected using these primers, the random amplified polymorphic DNA analysis had the ability to differentiate T. asperellum, T. virens and F. solani. The capability of two Trichoderma spp. to suppress F. solani is through formation of loops and coils and attachment of hyphal tips. They also had the ability to produce Chitinase and volatile metabolites that controlled the growth of F. solani.

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.

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