Consumer transparency in the production chain for plant varieties produced using new genomic techniques.

Plants edited with new genomic techniques (NGTs) currently fall under the Genetically Modified Organisms Directive (2001/18/EC) in the European Union. In the proposal of the European Commission, NGT plants are partially exempted from the regulations of this directive. The proposal makes a distinction between two categories of NGT plants: NGT-1 and NGT-2. NGT-1 category plants are considered equal to plants obtained through conventional breeding methods. These plants will not be labelled for the consumer, although they will be labelled as seeds. NGT-2 category plants may be labelled with additional information as a positive incentive. Labelling of seeds of varieties made with gene editing, but not the products, would mean that most steps in the production chain are transparent, but not the last step towards consumers. The "right to know" and increasing knowledge of gene-edited food is a common theme in food labelling towards consumers. Here, we describe current labelling regimes and registers and how these may be applied to provide transparency on gene-edited products to consumers. Furthermore, we also look into consumer studies, which indicate a greater acceptance of gene-edited food among consumers, especially when additional benefits such as sustainability are mentioned.

Correction to: New traits in crops produced by genome editing techniques based on deletions.

[This corrects the article DOI: 10.1007/s11816-017-0425-z.].

New traits in crops produced by genome editing techniques based on deletions.

One of the most promising New Plant Breeding Techniques is genome editing (also called gene editing) with the help of a programmable site-directed nuclease (SDN). In this review, we focus on SDN-1, which is the generation of small deletions or insertions (indels) at a precisely defined location in the genome with zinc finger nucleases (ZFN), TALENs, or CRISPR-Cas9. The programmable nuclease is used to induce a double-strand break in the DNA, while the repair is left to the plant cell itself, and mistakes are introduced, while the cell is repairing the double-strand break using the relatively error-prone NHEJ pathway. From a biological point of view, it could be considered as a form of targeted mutagenesis. We first discuss improvements and new technical variants for SDN-1, in particular employing CRISPR-Cas, and subsequently explore the effectiveness of targeted deletions that eliminate the function of a gene, as an approach to generate novel traits useful for improving agricultural sustainability, including disease resistances. We compare them with examples of deletions that resulted in novel functionality as known from crop domestication and classical mutation breeding (both using radiation and chemical mutagens). Finally, we touch upon regulatory and access and benefit sharing issues regarding the plants produced.

Reduction of herbicide use and emission by new weed control methods and strategies.

Highlights of a multidisciplinary research program on innovative weed control are presented and discussed in this paper. The program was carried out from 1999 to 2002, and dovetailed most fundamental-strategic and applied research aspects in The Netherlands in that period with respect to weed management. The program was focused on both developing and implementing sustainable weed control strategies for agricultural and non-agricultural areas. Some projects in the program were on (1) developing and improving weed preventive and non-chemical methods, (2) methods that allow the farmer to apply lower dosage of herbicides than indicated on the label, e.g. the so-called "Minimum Lethal Herbicide Dose method" (MLHD), and (3) rational weed control on hard surfaces. The main results of these projects are presented. A successful development and implementation of new methods and systems of weed control that use considerably less herbicides, is determined by many factors. The role that these success factors played in the aforementioned projects is shortly discussed.

Modelling for precision weed management.

Recently, the need for the development of weed management systems with a reduced dependency on herbicides has increased because of concern about environmental side-effects and cost. The development of such systems requires new strategies based on improvements with respect to (1) prevention, (2) decision making and (3) weed control technology. For the development of improvements in all three aspects, quantitative understanding of weed population dynamics and crop-weed interactions is needed. Models that integrate the available quantitative knowledge can be used to design preventive measures, to develop long-term and short-term strategies for weed management, to assist in decision making to determine if, when, where and how weeds should be controlled and to identify new opportunities for weed control. Ecophysiological simulation models for crop-weed competition simulate growth and production of species in mixtures, based on ecophysiological processes in plants and their response to the environment. Such models help improve insight into the crop-weed system and can be used for purposes such as the development of simple predictive yield-loss models, threshold levels or the design of competitive crop plant types. For strategic weed management decisions, preventive measures and the identification of new opportunities for weed control, quantitative insight into the dynamics and spatial patterns of weed populations is also required. The complexity of the process and the long-term character of weed population dynamics make the use of models necessary. Different modelling approaches have been developed and are described briefly. Opportunities to use the available knowledge and models to improve weed management are discussed. Weeds occur in patches and their sensitivity to herbicides changes strongly with developmental stage, making precision techniques for herbicide application in time and space an option for reducing herbicide use. Limitations related to insight in biological processes as well as the state of technological development are discussed.

Within-population variability in morphology and life history of Plantago major L. ssp. pleiosperma Pilger in relation to environmental heterogeneity.

An attempt was made to relate variation in life-history characteristics within a population of Plantago major ssp. pleiosperma to small-scale environmental variability. At a beach plain, embanked in 1966, a mosaic environment was distinguished with spatial variability in vegetation structure as well as in nutrient availability and water content of the soil. Differences between three subsites in comtemporary selection were demonstrated, e.g. in shoot morphology and allocation to reproductive tissue. The effects of nutrient supply and waterlogging on morphology and life history were studied on lines from the three subsites in a greenhouse. For most of the traits high levels of phenotypic plasticity were observed, covering almost entirely the observed phenotypic variability at the beach plain. In all treatments lines from the shrubs had, however, a higher leaf-area ratio as well as delayed flowering when compared to lines from more open subsites. In addition, in a reciprocal transplant experiment it was demonstrated that lines from the shrubs had larger shoots with e.g. broader leaves in the shady environment of the shrubs than other lines.From the experiments no indications were obtained that lines from any subsite were especially adapted to specific levels of nutrient supply or water content of the soil. With respect to these environmental factors P. major ssp. pleisoperma might occur and reproduce at all subsites by means of phenotypic plasticity, e.g. in plant form. However, it is suggested that spatial variability in vegetation structure caused a population subdivision in allocation patterns, leaf form and life history at the beach plain, over distances of about 15-25 m. This differentation occurred during primary succession over a period of twenty years.

Plasticity in life-history traits of Plantago major L. ssp. pleiosperma Pilger.

Plasticity in life-history characteristics was investigated in three populations of Plantago major L. ssp. pleiosperma (Pilger), a self-compatible, wind pollinated species with a high self-fertilization rate. The populations studied were selected for their marked differences in biomass accumulation and habitat characteristics such as nutrient availability and interspecific interaction. Plants, raised from seeds collected at three sites, were grown in a greenhouse at three nutrient levels. In addition, a reciprocal transplant experiment was carried out. In both experiments variances in variables of growth and reproduction were largely due to environmental factors. Besides this overall result, population and population x environment interaction effects existed for most of the variables. Differences in plasticity between populations were further analysed. In the greenhouse experiment plants from a river-side population showed a high degree of plasticity in reproductive effort, whereas plants from two other populations, one series from a beach plain and the other from a salt meadow, showed a high degree of plasticity in shoot-root ratio. Plasticity in biomass allocation to either vegetative or generative parts is suggested to be an important response to selective forces related to either interspecific competition or temporal variability.