Can rice genetic diversity reduce Echinochloa crus‐galli infestation?

Abstract

SummaryPot and field experiments were conducted to test whether rice genetic diversity can reduce Echinochloa crus‐galli infestation through rice variety mixed‐plantings. Two weed‐suppressive rice (Oryza sativa) varieties, Guodao No. 1 (GD) and PI312777 (PI), and three non‐suppressive varieties, Xiushui No. 63 (XS), Zhongjian No. 2 (ZJ) and Chunjiang No. 016 (CJ) were used. Monocultures (GD, PI, XS, ZJ and CJ), two‐variety mixtures (GD + XS, GD + ZJ, GD + CJ, PI + XS, PI + ZJ, PI + CJ) and three‐variety mixtures (GD + PI + XS, GD + PI + ZJ and GD + PI + CJ) were tested. Effects of herbicide on rice grain yield of non‐suppressive varieties were compared between monocultures and mixtures. Pot experiment showed that E. crus‐galli germination rate in all mixed‐planting except CJ + PI, and E. crus‐galli biomass in mixed‐planting with GD decreased compared with monocultures. In a field experiment, E. crus‐galli density decreased in all mixed‐planting models of XS and CJ and ZJ + GD. Echinochloa crus‐galli biomass reduction was found in XS + GD, XS + GD + PI, ZJ + GD and CJ + GD. Rice grain yield increased in XS + GD, ZJ + GD, CJ + GD, CJ + PI and CJ + GD + PI. Rice grain yields of non‐suppressive varieties under mixtures without herbicides were lower than that in monoculture with full herbicide, but were not significantly different from monocultures with half rate herbicide. Moreover, rice yields of ZJ and CJ under mixtures with half rate herbicides did not decrease compared with monocultures with full rates. The results suggested that rice genetic diversity could reduce E. crus‐galli infestation and herbicide utilisation through rice variety mixed‐planting.