Biological nitrogen fixation (BNF) in soybean is vulnerable to drought;however, there are genotypic variations among soybean cultivars regarding the ability to keep BNF under moderate water restriction. The aim of thi...Biological nitrogen fixation (BNF) in soybean is vulnerable to drought;however, there are genotypic variations among soybean cultivars regarding the ability to keep BNF under moderate water restriction. The aim of this study was to evaluate parameters related to gas exchanges and regulation of BNF in soybean genotypes BNF drought-tolerant (R01-581F and R01-416F), or drought-susceptible (CD 215 and BRS 317), submitted to adequate water supply or restriction between 45 and 55 days after emergence. We searched for traits associated with tolerance/susceptibility to drought, which might be useful in the selection of drought-tolerant soybean genotypes. Plant biomass was not affected under water restriction, but the number and dry weight of nodules reduced by 33% and 12%, respectively, in the average of genotypes. Drought-tolerant genotypes were more effective in maintaining gas exchanges under water restriction. Under water restriction, all genotypes increased the concentration of ureides in nodules, but only the susceptible genotypes showed that in leaves. The maintenance of gas exchanges and N metabolism regulation under water restriction in genotype R01-581F suggests that these parameters may be used to characterize soybean genotypes that can be sources of drought tolerance in genetic breeding programs.展开更多
Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory framewor...Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory frameworks that underpin these outcomes are based on a list of requirements for a risk assessment that differ from country to country.In recent years,policymakers have had the opportunity to learn from the controversies over transgenics to create effective regulatory milestones for emerging technologies,allowing them to reach their potential for a more sustainable agriculture,ensuring food security.In Brazil,Law No.11.105 of 24 March 2005 established a framework with four main organizations responsible for risk assessment and management.However,most of new breeding technologies did not exist at that time and were not considered in this law.In2016,Normative Resolution No.16 of the National Biosafety Technical Commission(CTNBio)was established to address this gap based on the evaluation of the products obtained through these techniques(termed Innovative Precision Improvement Techniques in the resolution),in a case-by-case consultation system.Briefly,if the product is designated to be a GM,the developer will have to go through the biosafety requirements and will be approved only after CTNBio risk assessment.If the product is designated not to be GM(for the purposes of the legislation),then it can be registered using the existing procedures.Currently,152 GM products are commercially approved in Brazil.In 2018,CTNBio assessed the first consultation on commercial release of plants generated using the new breeding technologies and has subsequently approved six products.It is expected that many institutions would be able to participate in Brazilian and world markets,developing and introducing new biotechnological solutions and products through a more sustainable approach and without facing public disapproval,a common issue for GM crops.展开更多
文摘Biological nitrogen fixation (BNF) in soybean is vulnerable to drought;however, there are genotypic variations among soybean cultivars regarding the ability to keep BNF under moderate water restriction. The aim of this study was to evaluate parameters related to gas exchanges and regulation of BNF in soybean genotypes BNF drought-tolerant (R01-581F and R01-416F), or drought-susceptible (CD 215 and BRS 317), submitted to adequate water supply or restriction between 45 and 55 days after emergence. We searched for traits associated with tolerance/susceptibility to drought, which might be useful in the selection of drought-tolerant soybean genotypes. Plant biomass was not affected under water restriction, but the number and dry weight of nodules reduced by 33% and 12%, respectively, in the average of genotypes. Drought-tolerant genotypes were more effective in maintaining gas exchanges under water restriction. Under water restriction, all genotypes increased the concentration of ureides in nodules, but only the susceptible genotypes showed that in leaves. The maintenance of gas exchanges and N metabolism regulation under water restriction in genotype R01-581F suggests that these parameters may be used to characterize soybean genotypes that can be sources of drought tolerance in genetic breeding programs.
文摘Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory frameworks that underpin these outcomes are based on a list of requirements for a risk assessment that differ from country to country.In recent years,policymakers have had the opportunity to learn from the controversies over transgenics to create effective regulatory milestones for emerging technologies,allowing them to reach their potential for a more sustainable agriculture,ensuring food security.In Brazil,Law No.11.105 of 24 March 2005 established a framework with four main organizations responsible for risk assessment and management.However,most of new breeding technologies did not exist at that time and were not considered in this law.In2016,Normative Resolution No.16 of the National Biosafety Technical Commission(CTNBio)was established to address this gap based on the evaluation of the products obtained through these techniques(termed Innovative Precision Improvement Techniques in the resolution),in a case-by-case consultation system.Briefly,if the product is designated to be a GM,the developer will have to go through the biosafety requirements and will be approved only after CTNBio risk assessment.If the product is designated not to be GM(for the purposes of the legislation),then it can be registered using the existing procedures.Currently,152 GM products are commercially approved in Brazil.In 2018,CTNBio assessed the first consultation on commercial release of plants generated using the new breeding technologies and has subsequently approved six products.It is expected that many institutions would be able to participate in Brazilian and world markets,developing and introducing new biotechnological solutions and products through a more sustainable approach and without facing public disapproval,a common issue for GM crops.
