Chennellu – A resistant variety of traditional rice cultivar in Kerala against bacterial blight

Chennellu is one of the medicinal rice of Kerala and are indigenous to Northern Kerala. Chennellu in Kannur district is used for treat in diarrhea and vomiting, another type of Chennellu called ‘Valiya Chennellu’ from Wayanad district is used for recovering from jaundice. Chennellu, the red rice, is also a good source of Vitamin B1. In Asia, a large number of the population consumes rice in every meal and rice accounts for more than 70% of human caloric intake in many countries. Even though the average cost of rice production is highest in Kerala when compared to other states in India; it is a hot spot for pests and diseases. The high humidity and temperature of the rice growing environments during the cropping periods increases the incidence of diseases. Bacterial blight is one of major disease of rice in Kerala caused by Xanthomonas oryzae pv. oryzae (Xoo) and is a reason for severe damage to rice crop in Kerala. Adukkan, Ayiramkana, Chennellu, Chomala, Gandhakasala, Kayma, Valichoori, Veliyan and Thondi were the local rice varieties in North Kerala used for finding out the susceptibility of Xoo. The field grew 45 days old rice plants were inoculated with 2.5µl, 5µl, 10µl and 25µl of the supernatant of 48-hour old Xoo broth culture at a concentration of approximately 108 CFU/mL (0.5OD600nm). Inoculations by creating wounds were carried out manually on the leaves with sterile forceps. Plants were visually examined after 21 days for bacterial blight severity, and the lesion length of each leaf was measured. Disease reactions were categorized according to the lesion length. Variation in lesion length across different concentration was tested individually for each rice variety with one-way ANOVA. During bacterial infection, the mean lesion length was least at the concentration of 2.5µl in Chennellu (0.5cm). In this study, it was concluded that Chennellu is the resistant rice cultivar against bacterial blight among other traditional rice cultivars commonly used.