Transgene flow to hybrid rice and its male-sterile lines

Abstract

Gene flow from genetically modified (GM) crops to the same species or wild relatives is a major concern in risk assessment. Transgenic rice with insect and/or disease resistance, herbicide, salt and/or drought tolerance and improved quality has been successfully developed. However, data on rice gene flow from environmental risk assessment studies are currently insufficient for the large-scale commercialization of GM rice. We have provided data on the gene flow frequency at 17 distances between a GM japonica line containing the bar gene as a pollen donor and two indica hybrid rice varieties and four male-sterile (ms) lines. The GM line was planted in a 640 m2 in an isolated experimental plot (2.4 ha), which simulates actual conditions of rice production with pollen competition. Results showed that: (1) under parallel plantation at the 0-m zone, the transgene flow frequency to the ms lines ranged from 3.145 to 36.116% and was significantly higher than that to hybrid rice cultivars (0.037-0.045%). (2) Gene flow frequency decreased as the distance increased, with a sharp cutoff point at about 1-2 m; (3) The maximum distance of transgene flow was 30-40 m to rice cultivars and 40-150 m to ms lines. We believe that these data will be useful for the risk assessment and management of transgenic rice lines, especially in Asia where 90% of world's rice is produced and hybrid rice varieties are extensively used.

Innate factors causing differences in gene flow frequency from transgenic rice to different weedy rice biotypes

“…The surviving glufosinate‐resistant seedlings were then transplanted into another nursery. After growth recovery, 400 g ha −1 glufosinate was applied to the surviving seedlings as a third treatment 28. The percentage outcrossing was estimated on the basis of the number of hybrids and the total number of herbicide‐treated weedy rice plants.…”

Evaluation of Gene Flow from GM to Non-GM Rice

“…Even though the out-crossing rate between cultivated rice and weedy rice is very low, both have high sexual compatibility (Song et al 2002;Song et al 2003;Song et al 2004;Messeguer et al 2004). Several studies that used male-sterile lines reported that rice pollen can be dispersed to more than 100 m Jia et al 2007;Yuan et al 2007). With this information, gene flow from cultivated rice to wild or weedy rice was proven to be continuously happening in the field naturally.…”

Direct and reverse pollen-mediated gene flow between GM rice and red rice weed

“…2011) and even when GM and conventional plants were mixed together on the same plot (Rong et al . 2005; Jia et al . 2007).…”