Diversity of Echinochloa spp. in Palakkad rice tracts of Kerala

Surveys were conducted twice in the major rice tracts of Palakkad, once during January-February, and the other during August-September in 2016. Three major Echinochloa types were identified infesting rice fields, causing severe crop competition. The three types were E. colona, with awnless spikelets and two types of E. crus-galli, viz. E. crus-galli (type A) having short awns and E. crus-galli (type B) having long awns. Other than the length and arrangement of awns, there were no significant differences in the morphological characters of the latter two types. Frequency and relative frequency was the highest for E. crus-galli (type B). There was no specific association between the Echinochloa types and soil nutrient parameters, probably as there were no drastic differences in the chemical properties among the different locations. Cluster analysis classified Echinochloa types in to 5 groups at 66.67% similarity level. The study concludes that in a less productive environment, the awned types of Echinochloa could have a better chance of survival.