Classification Of Echinochloa Species And Their Allelopathy With Rice

Most Echinochloa species in the grass family are serious weeds throughout the world, causing severe damage to many crops, particularly to rice.The application ofallelopathy appears to be potentially severed as an alternative weed management strategy for crop production without environmental cost. So far, numerous researcheson allelopathy between rice and barnyardgrass have been reported. However, most of these studies usually involved only one or two species of barnyardgrass, or even ignored the species differences. Our present study performed Echinochloa species identification using flow cytometry and molecular markers. We then used RSA (Relay Seedling in Agar) method to evaluate the allelopathic effects of different Echinochloa species on three rice cultivars. The main findings are as follows:1. A total of 49 barnyardgrass materials were classified into twogroups,in which 13 of them were E. oryzicola and 36 were E. crus-gallibased on flow cytometry and/or molecular markers.The E. crus-galli were further classified intoE. crus-galli var crus-galli.(19),E. crus-galli var praticola. (6),E. colona(1) andanotherunknown Echinochloa specie (7) by a SNP marker.2. Three rice cultivarsshowedthe same allelopathypotential to one barnyardgrass material, showing that these three rice cultivars had the same effect (promotion or inhibition) on the growth of one barnyardgrass material. However, this effect is not Echinochloaspecies dependent.The allelopathy of rice to different barnyardgrasses is also not Echinochloaspecies dependent.3. E. oryzicola showed weaker allelopathic potential to rice than E. crus-galli.But there seems no significant differencesamongE. crus-gallivarieties.