Title: Evaluation of the reaction of major weeds and some rice cultivars to Colletotrichum graminicola
Abstract: Alisma plantago-aquatica, Sagitaria trifolia and Echinochloa spp. are among the most important damaging weeds of rice paddies. In this research, Colletotrichum graminicola was isolated from these weeds and studied as a biological agent for controllingweeds. To do so, at first, reactions of five rice cultivars including three indigenous cultivars such as Hashemi, Ali Kazemi and Binam and two bred ones, i.e. Sepidroudand Khazar to Colletotrichum graminicola were evaluated. Thus, a complete random design with three replications and five treatments was used at a greenhouse. Then, Colletotrichum graminicola was inoculated on these weeds. The experimental design was a randomized completed with three replications. Inoculation was done at the 3-4-leaf stage using a spore suspension consisting of 10conidia/mL distilled water to which Tween-20 1% was added. Results showed that Colletotrichum graminicola caused high disease ratings in Alisma plantago-aquatica, Sagitaria trifolia, E. crus-galli and E. oryzicola, respectively. In addition, the studied rice cultivars showed a significant reaction in terms of the disease rating among which bred cultivars were less tolerant. Moreover, the fungus reduced fresh weight, dry weight and height in the studied weeds and rice cultivars. Therefore, C. graminicola can be used as a mycoherbicide for the biological control of these weeds only when other cultivars except the above-mentioned rice cultivars are planted. This issue particularly requires producing new tolerant cultivars with a combination of the desired traits. [Mohammad Reza Safari Motlagh and Armin Javadzadeh (2011). Evaluation of the Reaction of Major Weeds and Some Rice Cultivars to Colletotrichum graminicola. Journal of American Science. 7(2):179-185].