Environment Brazil , Brasil, Wednesday, July 23 of 2014, 12:35

Brazilian plants may help to mitigate impact of climate change

Studying the genomes of heat- and drought-tolerant species (such as the pequi) from the semi-arid and Cerrado regions may contribute to the genetic improvement of crops such as soya, maize, rice and beans

Noêmia Lopes/Agência FAPESP/DICYT The seriguela (Spondias purpurea) and umbuzeiro (Spondias tuberosa), trees commonly found in Brazil’s northeastern semi-arid region, and the Brazilian chestnut, native to the Cerrado, are part of a group of plants that could play an important role in agriculture by mitigating the consequences of climate change. They are among several Brazilian species that have enhanced adaptive capacity and are heat and drought tolerant.


Studying the genomes of these species could help to make crops such as soya, maize, rice and beans equally resistant to climate extremes, according to Eduardo Assad, a researcher at the National Center for Technology Research in Computer Sciences (CNPTIA) at the Brazilian Agricultural Corporation (Embrapa). Assad was one of the speakers at the fourth meeting of the 2014 Biota-FAPESP Education Conference Cycle, held on May 22 in São Paulo.


“The Cerrado used to be much hotter and dryer, and trees such as the pau-terra (Qualea parviflora Mart.), pequi and Brazilian yellow poinciana (Peltophorum dubium), not to mention the Brazilian chestnut, all survived. We need to study the genomes of these trees so we can identify and isolate the genes that make them so adaptable. This could mean that one day, we’d have the chance to genetically improve crops such as soya and maize, making them similarly resistant,” he said. “It won’t be easy, but we need to get started.”


Assad noted that Brazil is a leader in drought-resistant species. “The world’s largest storehouse of genes that are tolerant to global warming is here in the Cerrado and in the semi-arid Northeast,” he said in his lecture, which was titled “The potential impact of climate change on agriculture.”


The research models developed by Embrapa, many in collaboration with institutions from 40 other countries, suggest that the reduced productivity observed in crops such as maize, soya and rice due to climate change is expected to become more pronounced in the coming decades. “This applies to current genetic varieties. One possible solution is to look for alternative genes to work on improving these varieties,” Assad said.


Other plants of the Cerrado with enhanced adaptive capacity that were mentioned by the researcher are the pacari tree (Lafoensia pacari) and the fruit of the baru (Dipteryx alata) and cagaita (Stenocalyx dysentericus). In the semi-arid Northeast, trees such as the Brazilian chestnut, the umbuzeiro and the cajá have been identified as important options, not only for genetic studies but also for programs designed to generate income for the local population.


“Instead of growing crops that are exotic to the region, we need to invest in those that are already part of the biodiversity of the Northeast and have the potential to overcome the consequences of global warming,” Assad said.


To increase tolerance to abiotic stress, Embrapa is planning to introduce a drought-resistant soybean in 2015, which was produced by introducing a gene from a Japanese plant. “We’re testing this variety in the state of Paraná this year, during the dry season. Studies still need to be done, but things are going quite well,” the researcher said.


Assad also mentioned progress made by the Agronomic Institute of Paraná (IAPAR), which has already introduced four heat-tolerant bean cultivars, in addition to conducting studies in the municipality of Varginha (state of Minas Gerais) in search of more heat-tolerant varieties of coffee.


Losses and changes in productivity


Embrapa’s calculations based on average soybean productivity show that this grain alone accrued more than US$8.4 billion in losses related to climate change in Brazil between 2003 and 2013. Corn production lost more than US$5.2 billion during the same period.


According to analyses conducted at Embrapa and the University of Campinas (Unicamp), the number of low-risk areas for the cultivation of Arabica coffee is expected to diminish by 9.45% by 2020 and by 17.15% by 2050, causing losses of R$882 million and R$1.6 billion, respectively.


In the face of such losses, another suggestion by Assad is to overhaul the agricultural production model. “The concentration of greenhouse gases in the atmosphere has increased over 20% in the last 30 years, making implementation of cleaner production systems critical,” he told Agência FAPESP.


“Brazil is highly respected with regard to this topic, particularly because it has managed to both reduce deforestation and increase productivity in the Amazon region,” he said.


According to Assad, this situation opens up channels for dialog about sustainable agriculture and the adoption of strategies such as the integration of crops, cattle-raising areas and forests; direct planting in straw; the use of nitrogen-fixing bacteria in the soil; the use of stone meal (which contains micro- and macro-nutrients, to improve soil fertility); the application of organomineral fertilizers; and genetic improvements.


“Cattle confinement is another subject for discussion by researchers and livestock farmers in many parts of the world. It could result in lower greenhouse gas emissions, but it makes the herd more vulnerable to mad cow disease. In this case, an alternative would be to restore degraded pastures,” Assad said.


Studies conducted at Embrapa’s Agrobiology Unit show that one kilogram (kg) of meat produced in degraded pastures emits more than the equivalent of 32 kg of CO2 per year. However, in recovered pastures that accommodate low carbon-emission agriculture, the emission per kg of meat may be reduced by up to the equivalent of three kg of CO2 annually.


“This shows that environmentalists, land owners, the government and the private sector need to sit down and decide what they need to do from this point on. What production system will they use? Will it include pastures or not? Will it include trees or not? Will it be rotated or not? These are difficult long-term changes, but many farmers are already concerned about these issues and the losses that global warming could bring, and they are beginning to look for solutions,” he said.