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ADVERSE IMPACTS OF TRANSGENIC CROPS/FOODS :A COMPILATION OF SCIENTIFIC REFERENCES WITH ABSTRACTSto assess the occurrence of wild poinsettia (Euphorbia heterophylla, EPHHL)resistant biotypes to glyphosate. Two suspected glyphosate- resistant biotypesfrom the northern part of Rio Grande do Sul, Brazil, were compared to knownglyphosate-susceptible biotypes. Dose-response curves were used to comparethe biotypes, with rates ranging from 0 to 450 g ha -1 in one experiment, and from0 to 1200 g ha -1 in another. The resistance factor, calculated with the I 50data,indicated the resistant biotypes were about three times less sensitive toglyphosate than the susceptible biotypes. This is the first report of a glyphosateresistantbiotype in a weed species of major importance and distribution in Brazil.A risk analysis is discussed for the occurrence of glyphosate-resistant wildpoinsettia in glyphosate-tolerant soybeans.14. Sandermann H. (2006) : Plant biotechnology: ecological case studies onherbicide resistance. Trends in Plant Science 11 (7), 324–328.The emerging field of molecular ecology aims to improve the ecologicalpredictability of transgenic crop plants. The most widely cultivated lines areRoundup- Readyw plants, which are genetically modified to be resistant to thebroad-spectrum herbicide glyphosate. Recent publications demonstrate twoecological effects that were not anticipated: the widespread emergence ofglyphosate-resistant weed biotypes and the formation of a metabolic herbicidalresidue. Both effects appear to be due to the increased use of glyphosate ratherthan the genetic modification in the transgenic crop plant. With one prominentexception, opinions collected from the literature point towards a certain degree ofresistance mismanagement and an inadequate testing of the ecological effectsof extensive glyphosate use.15. Owen M D K and Zelaya I A (2005) : Herbicide-resistant crops and weedresistance to herbicides. Pest Manag. Sci. 61: 301-311.The adoption of genetically modified (GM) crops has increased dramatically duringthe last 3 years, and currently over 52 million hectares of GM crops are plantedworld-wide. pproximately 41 million hectares of GM crops planted are herbicideresistantcrops, which includes an estimated 33.3million hectares of herbicideresistantsoybean. Herbicide-resistant maize, canola, cotton and soybeanaccounted for 77% of the GM crop hectares in 2001. However, sugarbeet, wheat,and as many as 14 other crops have transgenic herbicide-resistant cultivars thatmay be commercially available in the near future. There are many risks associatedwith the production of GM and herbicide-resistant crops, including problems withgrain contamination, segregation and introgression of herbicide-resistant traits,marketplace acceptance and an increased reliance on herbicides for weed control.The latter issue is represented in the occurrence of weed population shifts, theevolution of herbicide-resistant weed populations and herbicide-resistant cropsbecoming volunteer weeds. Another issue is the ecological impact that simpleweed management programs based on herbicide-resistant crops have on weedcommunities. Asiatic dayflower (Commelina cumminus L) commonlambsquarters (Chenopodium album L) and wild buckwheat (Polygonum(120)