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Germination and seedling emergence of glyphosate-resistant and susceptible biotypes of goosegrass (Eleusine indica[L.] Gaertn.)

Authors


Correspondence to: B.S. Ismail, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43 600 Bangi, Selangor, MalaysiaEmail: ismail@pkrisc.cc.ukm.my

Abstract

Effects of environmental factors on the germination and seedling emergence of glyphosate-resistant (R) and -susceptible (S) biotypes of Eleusine indica (L.) Gaertn. were examined under laboratory and greenhouse conditions. The R biotype exhibited a higher germination percentage compared with the S biotype at constant temperatures of 20 and 35°C under dark conditions, and alternating temperatures of 30/25°C, and 35/25°C during a 12 h photo period. For both biotypes, germination was optimal at alternating temperatures of 30/20°C and 35/20°C. However, there was no significant difference (P > 0.05) in the germination between the R and S biotypes at these temperature regimes. The germination of both biotypes was inhibited by osmotic stress imposed by a water potential of −0.80 MPa. When the moisture stress was released and the seeds were subsequently transferred to distilled water, the germination was enhanced to approximately 90% and 16% for the R and S biotype seeds, respectively. Higher emergence rates were obtained in shallow seed depths (0 or 2 cm) compared to deep depths. Emergence percentage of the R biotype was higher than that of the S biotype at 0 cm and 2 cm depths. The maximum emergence percentage of the R biotype was higher than that of S biotype when seeds were sown on the surface of either loamy or clay loam soil taken from three different sites.

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