Jueves, 22 Diciembre 2016 16:58

Development of a new method for weed control

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This is the first study that describes the mechanisms of resistance to the herbicide glyphosate in Conyza sumatrensis, a very common broadleaf weed that is particularly harmful to citrus crops, vineyards and olive gro

Fundación Descubre

Fundación Descubre

This is the first study that describes mechanisms of resistance to the herbicide glyphosate in Conyza sumatrensis, a very common broadleaf weed that is particularly harmful to citrus crops, vineyards and olive groves

Fundación Descubre

This is the first study that describes mechanisms of resistance to the herbicide glyphosate in Conyza sumatrensis, a very common broadleaf weed that is particularly harmful to citrus crops, vineyards and olive groves

esearchers from the Plant Breeding Department of the Institute for Sustainable Agriculture (IAS) and Soil Science and the Agricultural Chemistry Department of the University of Cordoba (UCO), which belong to the ceiA3  Agrifood Campus of International Excellence, have developed the first international study which describes resistance mechanisms of some weeds to the herbicide glyphosate, widely used in agriculture for elimination of weeds in woody crops. Researchers have focused on describing the mechanisms of defense of Conyza sumatrensis, one of the most common and harmful threats in agriculture in Western Andalusia and Valencia.
In the article 'First evidence for a mutation in the target site EPSPS2 gene in glyphosate -resistant citrus orchards from Sumatran fleabane”, published in the journal Agronomy for Sustainable Development, the team of experts describes the mechanisms of protection of Conyza sumatrensis when the weed has to ' face ' the action of the herbicide glyphosate. 'Results show that the main resistance factors are based on a genetic mutation. In this regard, we have identified and analyzed the behaviour of Conyza sumatrensis, a species that had never been studied before and which is also primarily responsible for the poor efficacy of glyphosate in certain agricultural crops', explained Rafael De Prado, researcher from the University of Cordoba, to Fundación Descubre.
Field assays were carried out in a citrus field located in the province of Huelva. 'Firstly, after making a field exploration, we collected seeds from a Conyza sumatrensis population which had been exposed to glyphosate for at least ten years. Then, we selected a second sample of this weed seeds from the same region except that they had remained for a year in a greenhouse, always under controlled laboratory conditions', explains the researcher.
He adds: ' Finally, after comparing the two groups of seeds, we performed the appropriate physiological, biochemical and molecular assays to determine differences and identify the mechanisms of resistance to glyphosate herbicide'.
Alternative measures
Despite the efficiency shown by herbicides in controlling weeds, the present study represents, according to the researchers, a further step which highlights the importance of diversifying control strategies for invasive broadleaf weeds. 'In olive crops, vineyards or citrus crops, improper and excessive use of herbicides against scrub leads to appearance of new, increasingly more resistant species. Therefore, introduction of new alternative measures would help to avoid sole reliance on these chemical tools and ensure a greater diversity of the ecosystem', says De Prado.
In fact, this work has enabled the team of experts to open new lines of research in order to study how these defense mechanisms function in response to other herbicides and in conditions. 'In addition to translating this laboratory trial into real field, we intend to further develop experiments with different types of herbicides and to apply alternative methods to determine the best control methods that will prevent the development of resistant biotypes', he explains.

Researchers from the Plant Breeding Department of the Institute for Sustainable Agriculture (IAS) and Soil Science and the Agricultural Chemistry Department of the University of Cordoba (UCO), which belong to the ceiA3  Agrifood Campus of International Excellence, have developed the first international study which describes resistance mechanisms of some weeds to the herbicide glyphosate, widely used in agriculture for elimination of weeds in woody crops. Researchers have focused on describing the mechanisms of defense of Conyza sumatrensis, one of the most common and harmful threats in agriculture in Western Andalusia and Valencia.

In the article 'First evidence for a mutation in the target site EPSPS2 gene in glyphosate -resistant citrus orchards from Sumatran fleabane”, published in the journal Agronomy for Sustainable Development, the team of experts describes the mechanisms of protection of Conyza sumatrensis when the weed has to ' face ' the action of glyphosate herbicide. 'Results show that the main resistance factors are based on a genetic mutation. In this regard, we have identified and analyzed behaviour of Conyza sumatrensis, a species that had never been studied before and which is also primarily responsible for the poor efficacy of glyphosate in certain agricultural crops', explained Rafael De Prado, researcher from the University of Cordoba, to Fundación Descubre.

Field assays were carried out in a citrus field located in the province of Huelva. 'Firstly, after making a field exploration, we collected seeds from a Conyza sumatrensis population which had been exposed to glyphosate for at least ten years. Then, we selected a second sample of this weed seeds from the same region except that they had remained for a year in a greenhouse, always under controlled laboratory conditions', explains the researcher.

He adds: 'Finally, after comparing the two groups of seeds, we performed the appropriate physiological, biochemical and molecular assays to determine differences and identify the mechanisms of resistance to glyphosate herbicide'.

Alternative measures

Despite the efficiency shown by herbicides in controlling weeds, the present study represents, according to the researchers, a further step which highlights the importance of diversifying control strategies for invasive broadleaf weeds. 'In olive crops, vineyards or citrus crops, improper and excessive use of herbicides against scrub leads to appearance of new, increasingly more resistant species. Therefore, introduction of new alternative measures would help to avoid reliance on these chemical tools and ensure a greater diversity of the ecosystem', says De Prado.

In fact, this work has enabled the team of experts to open new lines of research in order to study how these defense mechanisms function in response to other herbicides and in conditions. 'In addition to going from laboratory trials to real field studies, we intend to further develop experiments with different types of herbicides and to apply alternative methods to determine the best control methods that will prevent development of resistant biotypes', he explains.

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