Informal “Seed” Systems and the Management of Gene Flow in Traditional Agroecosystems: The Case of Cassava in Cauca, Colombia

Our ability to manage gene flow within traditional agroecosystems and their repercussions requires understanding the biology of crops, including farming practices' role in crop ecology. That these practices' effects on crop population genetics have not been quantified bespeaks lack of an appropriate analytical framework. We use a model that construes seed-management practices as part of a crop's demography to describe the dynamics of cassava (Manihot esculenta Crantz) in Cauca, Colombia. We quantify several management practices for cassava—the first estimates of their kind for a vegetatively-propagated crop—describe their demographic repercussions, and compare them to those of maize, a sexually-reproduced grain crop. We discuss the implications for gene flow, the conservation of cassava diversity, and the biosafety of vegetatively-propagated crops in centers of diversity. Cassava populations are surprisingly open and dynamic: farmers exchange germplasm across localities, particularly improved varieties, and distribute it among neighbors at extremely high rates vis-à-vis maize. This implies that a large portion of cassava populations consists of non-local germplasm, often grown in mixed stands with local varieties. Gene flow from this germplasm into local seed banks and gene pools via pollen has been documented, but its extent remains uncertain. In sum, cassava's biology and vegetative propagation might facilitate pre-release confinement of genetically-modified varieties, as expected, but simultaneously contribute to their diffusion across traditional agroecosystems if released. Genetically-modified cassava is unlikely to displace landraces or compromise their diversity; but rapid diffusion of improved germplasm and subsequent incorporation into cassava landraces, seed banks or wild populations could obstruct the tracking and eradication of deleterious transgenes. Attempts to regulate traditional farming practices to reduce the risks could compromise cassava populations' adaptive potential and ultimately prove ineffectual

Application of new breeding techniques in fruit trees

Climate change and rapid adaption of invasive pathogens pose a constant pressure on the fruit industry to develop improved varieties. Aiming to accelerate the development of better-adapted cultivars, new breeding techniques have emerged as a promising alternative to meet the demand of a growing global population. Accelerated breeding, cisgenesis, and CRISPR/Cas genome editing hold significant potential for crop trait improvement and have proven to be useful in several plant species. This review focuses on the successful application of these technologies in fruit trees to confer pathogen resistance and tolerance to abiotic stress and improve quality traits. In addition, we review the optimization and diversification of CRISPR/Cas genome editing tools applied to fruit trees, such as multiplexing, CRISPR/Cas-mediated base editing and site-specific recombination systems. Advances in protoplast regeneration and delivery techniques, including the use of nanoparticles and viral-derived replicons, are described for the obtention of exogenous DNA-free fruit tree species. The regulatory landscape and broader social acceptability for cisgenesis and CRISPR/Cas genome editing are also discussed. Altogether, this review provides an overview of the versatility of applications for fruit crop improvement, as well as current challenges that deserve attention for further optimization and potential implementation of new breeding technique

Investigations: The Expanded Field of Writing in the Works of Robert Morris

Yes, you seem to have been anything but an iconophile in your enterprise which is piled as high with words on one side as with images on the other. Robert Morris, “Professional Rules” By investigating the prolific oeuvre of Robert Morris via the prism of writing, this collection of essays provides an incisive lens into the work of a central figure in the visual arts since the 1960s, associated in turn with minimalism, postminimalism, conceptualism, and land art. Morris has often been labeled a theorist, although his writing mobilizes a wide variety of genres. He has espoused the style of art criticism, the verve of the polemic, as well as the forms of prose fiction and autobiography. But beyond his writerly craft, he has incorporated text into prints, sculptures, performances, installations, weaving a tight net between text and visual practice. This book brings together contributions from art historians, literary scholars, philosophers, filmmakers, and writers to shed light on an important yet overlooked aspect of Morris’ work. Illustration : Robert Morris, Investigations: Could I also Represent Hope in this Way? Hardly. And What about Belief?, 1990. Graphite on vellum, 18 × 18 inches (45.7 × 45.7 cm). Photo: Courtesy of Robert Morris and Sonnabend Gallery, New York. © 2010 Robert Morris/Artists Rights Society (ARS), New York.Oui, il semble que vous ayez été tout sauf un iconophile dans cette entreprise, où les mots s'accumulent autant d'un côté que les images de l'autre. Robert Morris, « Professional Rules » Cette collection d’articles parcourt l’œuvre de Robert Morris à travers le prisme de l'écriture, offrant ainsi une nouvelle lecture d’une œuvre centrale des arts plastiques depuis les années soixante, tour à tour associée avec le minimalisme, le conceptualisme ou encore le land art. Bien que Morris soit souvent taxé de théoricien, son œuvre écrite mobilise une importante variété de genres, de la critique d’art à la fiction et à l'autobiographie. Hormis cette pratique de la langue, l'écrit inséré dans ses estampes, ses sculptures, ses performances ou encore ses installations tisse un réseau serré entre texte et œuvre plastique. Ce livre rassemble des contributions d'historiens d'art, de chercheurs en lettres, de philosophes, mais aussi de cinéastes et d'écrivains