Evaluation of Gene Flow from GM to Non-GM Rice

Gene flow events from genetically modified (GM) rice to adjacent non-GM rice lines naturally happen in the field. GM rice lines containing desirable agronomic traits such as tolerance to abiotic stresses and resistance to biotic stresses can be used to cross with non-GM cultivated rice and also to wild species of rice. This event can eventually lead to offspring which possess traits that allows a better chance of survival in the field. However this phenomenon has the possibility to produce undesirable effect in the environment surrounding the rice field. The objective of this study was to determine the out-crossing rate of GM rice to cultivated rice. Transgenic rice, Hwangkembyeo (containing beta-carotene enhancing gene and bar gene) and cultivated rice, Nakdongbyeo (mother plant of Hwangkembyeo) were used in this study. Results showed that most gene flow events occurred within 1 m range. In particular, gene flow events mostly happened within 30 cm, while it was rarely observed beyond 90 cm range. The maximum distance for gene flow event was observed at 6 m range however the sharp cut point distance was observed at 60-90 cm range. The prevailing gene flow direction was Northwest (NW) which coincided with the prevailing wind of Southeastern (SE) direction. Wind direction and distance were found to be the most important factors for determining rice out-crossing rate. But for more accurate prevention of GM gene flow, many factors should be considered like the local weather condition, wind direction, wind speed and flowering time.