Stress and domestication traits increase the relative fitness of crop–wild hybrids in sunflower

Mercer, Kristin L.; Andow, David A.; Wyse, Donald L.; Shaw, Ruth G.

doi:10.1111/j.1461-0248.2007.01029.x

Cited by 104 publications

(159 citation statements)

References 72 publications

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“…Costs of genetic engineering have not previously been reported for these lines [15] or others [8,13] in the Brassica system, nor in Sunflower [14]. They were observed here perhaps because of the stresses imposed by the mesocosm environments [16]. Similar observations of fitness costs are not uncommon and have been observed in other studies, for example, studies on herbicide resistance traits (reviewed by [17]).…”

Section: Costs Of Bt Cry1ac Genesupporting

confidence: 85%

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

et al. 2015

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Field trials of transgenic crops may result in unintentional transgene flow to compatible crop, native, and weedy species. Hybridization outside crop fields may create novel forms with potential negative outcomes for wild and weedy plant populations. We report here the outcome of large outdoor mesocosm studies with canola (Brassica napus), transgenic canola, a sexually compatible weed B. rapa, and their hybrids. Brassica rapa was hybridized with canola and canola carrying a transgene for herbivore resistance (Bt Cry1Ac) and grown in outdoor mesocosms under varying conditions of competition and insect herbivory. Treatment effects differed significantly among genotypes. Hybrids were larger than all other genotypes, and produced more seeds than the B. rapa parent. Under conditions of heavy herbivory, plants carrying the transgenic resistance were larger and produced more seeds than non-transgenic plants. Pollen derived gene flow from transgenic canola to B. rapa varied between years (5%-22%) and was not significantly OPEN ACCESSAgronomy 2015, 5 22 impacted by herbivory. These results confirm that canola-weed hybrids benefit from transgenic resistance and are aggressive competitors with congeneric crops and ruderals. Because some crop and crop-weed hybrids may be competitively superior, escapees may alter the composition and ecological functions of plant communities near transgenic crop fields.

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Section: Costs Of Bt Cry1ac Genesupporting

confidence: 85%

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

et al. 2015

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“…A major thrust of crop-wild hybridization research uncovers the combinations of genetics and environment that promote introgression (e.g., Mercer et al, 2007 ). This parallels study of the relative importance of endogenous (acting regardless of environment) and exogenous (varying depending on environmental factors) selection in natural hybrid zones (e.g., Kimball et al, 2008 ).…”

Section: Discussionmentioning

confidence: 99%

“…Researchers also often increase the odds of successfully establishing a fi eld experiment by watering, weeding, or applying pest control. Such understandable decisions to reduce risk may affect hybrid fi tness given past work on environment-dependent hybrid performance (e.g., Mercer et al, 2007 ;Kimball et al, 2008 ). Third, it is crucial to recognize that many hybrid generations coexist in a hybrid zone: once an F1 hybrid is formed, subsequent crossing events produce later hybrid generations.…”

Section: Methodsmentioning

confidence: 99%

Roles of maternal effects and nuclear genetic composition change across the life cycle of crop–wild hybrids

Alexander

Emry

Pace

et al. 2014

American J of Botany

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• Premise of the study: The fi tness of an offspring may depend on its nuclear genetic composition (via both parental genotypes) as well as on genetic maternal effects (via only the maternal parent). Understanding the relative importance of these two genetic factors is particularly important for research on crop-wild hybridization, since traits with important genetic maternal effects (e.g., seed size) often differ among crops and their relatives. We hypothesized that the effects of these genetic factors on fi tness components would change across the life cycle of hybrids. • Methods: We followed seed, plant size, and reproductive traits in fi eld experiments with wild and four crop-wild hybrids of sunfl ower ( Helianthus annuus ), which differed in nuclear genetic composition and maternal parent (wild or F1 hybrid).• Key results: We identifi ed strong genetic maternal effects for early life cycle characteristics, with seeds produced on an F1 mother having premature germination, negligible seed dormancy, and greater seedling size. Increased percentages of crop alleles also increased premature germination and reduced dormancy in seeds produced on a wild mother. For mature plants, nuclear genetic composition dominated: greater percentages of crop alleles reduced height, branching, and fecundity.• Conclusions: Particular backcrosses between hybrids and wilds may differentially facilitate movement of crop alleles into wild populations due to their specifi c features. For example, backcross seeds produced on wild mothers can persist in the seed bank, illustrating the importance of genetic maternal effects, whereas backcross individuals with either wild or F1 mothers have high fecundity, resulting from their wild-like nuclear genetic composition.

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“…There are cases published showing that especially hybrids of cultivated species with wild species develop a higher fitness under stress [75]. A higher amount of gene flow for oilseed rape under extreme climatic conditions was reported [76].…”

Section: Environmental Risksmentioning

confidence: 99%

Cultivation-independent establishment of genetically engineered plants in natural populations: current evidence and implications for EU regulation

Bauer-Panskus

Breckling

Hamberger³

et al. 2013

Environ Sci Eur

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About 20 years after the market introduction of the first GM plants, we review whether or not uncontrolled spread occurred. We summarise cases documented in the scientific literature and derive conclusions for the regulation of the authorisation of new events. Several cases documented in North and Central America and Japan show that transgenes have spread beyond cultivation areas. Important examples are bentgrass (Agrostis stolonifera), oilseed rape (Brassica napus) and cotton (Gossypium hirsutum). Several factors can be identified as relevant for transgene dispersal in the environment. Grasses (Poaceae), in particular, show a high potential for persistence and invasiveness, and wild relatives that can cross with the crop plants are a major factor in the unintended spread of the transgenes. There are significant uncertainties in predicting which transgenes will escape and how they will interact with the environment. For example, climate change is likely to have a major impact on the invasive potential of some plant species. The uncontrolled spread of transgenes is therefore a remaining challenge for regulators. We discuss some of these issues in the context of EU regulations since these regulations explicitly refer to the precautionary principle in the assessment of uncertainties. We found the that the precautionary principle as established in EU Directive 2001/18 can only be applied where efficient measures are available to remove genetically engineered organisms from the environment should this become necessary. If a removal from the environment would not be practically feasible, undesirable developments could not be mitigated.

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Stress and domestication traits increase the relative fitness of crop–wild hybrids in sunflower

Cited by 104 publications

References 72 publications

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

Roles of maternal effects and nuclear genetic composition change across the life cycle of crop–wild hybrids

Cultivation-independent establishment of genetically engineered plants in natural populations: current evidence and implications for EU regulation

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