Extensive levels of agrochemicals used in rice cultivation has caused serious environmental and
health problems in Sri Lanka. Therefore, safe and viable alternative strategies should be sought.
As endophytic fungi (EF) associated with many plants have been reported to have the ability to
enhance plant growth and also control diseases, they could be used for increased rice production
and disease management. However, before embarking on such an approach, the ability and rate
of colonization of a particular plant variety by EF should be assessed. Therefore, this study was
aimed at assessing the colonization rates (CRs) of EF present in a newly improved (At 362) and
a traditional (Suwandel) rice varieties grown in different geographical locations of Sri Lanka. Ten
healthy plants of each variety were collected during the Maha season (January, 2019) from
Anuradhapura, Kurunegala, Gampaha and Kalutara districts. Isolation of EF was carried out in
Malt Extract Agar, using 480 segments (60 segments including leaf, stem and root of each variety
from each location).
The difference in the extent of colonization by EF between two varieties,
among districts and between plant tissue types were analyzed separately by one-way ANOVA. A
total of 112 isolates (37 from At 362 and 75 from Suwandel) belonging to 39 different fungal
genera were isolated from both varieties collected from all four sites. Some of the isolates were
morphologically identified using a fungal identification key as Fusarium sp, Curvularia sp,
Penicillium sp, Acremonium sp, Paecilomyces sp, Colletotrichum sp, while the remaining were
sterile fungi. Statistical analysis showed that CRs of endophytes between the two rice varieties
differ significantly (P < 0.05).
However, there was no significant difference (P < 0.05) in CRs of
endophytic fungi in Suwandel between districts, whereas At 362 showed a significant difference
(P < 0.05) in CRs between districts. In addition, CRs among plant parts also differed significantly
(P < 0.05). In conclusion, endophytic fungal CRs varied between the two rice varieties (traditional
and newly improved) and the endophytic CRs in Suwandel was not affected by climatic and
associated conditions of different locations whereas that in At 362 was affected significantly.
