Abstract:
Economical and eco friendly weed control methods are very much important for the present agricultural production
systems due to over usage of chemicals in agriculture. Exploitation of allelopathic potential of different traditional
rice cultivars is a better solution for a sustainable weed management system. Genetic variation in allelopathic activity
among rice cultivars has been extensively demonstrated. In the present study allelopathic effect of rice straw of
traditional rice cultivars on germination percentage and plant height of Echinocloa crusgalli was evaluated in
laboratory experiments. Rice straw of thirty eight rice cultivars were separately mixed with non-rice grown sterilized
soils in four replicates using plastic cups (diameter 6 cm and height 5 cm). Surface sterilized Echinocloa crusgalli
seeds were sawn in decomposed soil samples. Control experiment was carried out in non-rice grown sterilized soil
samples collected in to the same sized plastic cups. Allelopathic effect of rice cultivars was evaluated according to
reduction of germination percentage and plant height of Echinocloa crusgalli in soil samples mixed with rice straw
compared to those of in control soil samples. Germination and growth of Echinocloa crusgalli were significantly
suppressed in soil samples prepared using rice straw of the most traditional rice cultivars. There was a positive
correlation between reduction of germination percentage and plant height (r=0.58923, a= 0.0001) of Echinocloa
crusgalli in soil samples mixed with straw of different rice cultivars. Ingirisi Wee, Bala Ma Wee, Karayal, and Lumbini
are the best allelopathic rice cultivars found in the present study. Rice cultivars those showed significantly higher
germination reductions and plant height in Echinocloa crusgalli can be further tested to confirm their allelopathic
effect at the field conditions.
