Where is the solution for food production in adverse conditions: high temperatures, climate change or attacks from pests and diseases? How to increase the productivity and nutritional quality of vegetables without neglecting the Brazilian food tradition? The answer certainly involves active germplasm banks (BAGs), which are structures that conserve germplasm samples – also known as accessions – and bring together the set of hereditary materials from species that guarantee the rich genetic variability, essential for research carried out in the scope of improvement programs.
Research carried out with the materials preserved in the BAGs makes it possible to develop new cultivars, ensuring the cultivation of food, many originating from other countries, in Brazil's climate and soil conditions. In addition to the innovative aspect that makes it possible to meet the demands of the production chain, banks have the function of conserving the wealth of genetic heritage.
Embrapa Hortaliças maintains germplasm banks and collections of 23 crops, totaling more than 10 thousand accessions incorporated into the BAGs through collections carried out in several Brazilian states and donations from farmers and national and foreign institutions. The number and origin of different places make banks extremely valuable in preserving the genetic diversity of the plant resources that make up our biodiversity.
In comparison, the BAG is similar to a library that keeps collections in its collection that keep the history, culture, habits and customs of the people alive; or even a safe, where people keep their most precious and valuable possessions. It is in this wealth of possibilities that researchers look for genetic materials that are sources of characteristics, such as resistance to pests and diseases, productivity and efficiency in the absorption and use of nutrients, necessary for the development of new cultivars. Thanks to these findings, research is contributing to the supply of increasingly healthier foods, reducing the excessive use of agricultural pesticides, and, consequently, causing less impact on the environment.
This detailed work, carried out within the scope of plant breeding programs, involves a multidisciplinary team of professionals responsible for the launch of more than 100 cultivars in the almost four decades of Embrapa Hortaliças' existence.
Each of these cultivars synthesizes years of research and, despite being a constant source of consultation, researchers are surprised by the genetic variability of the materials available in BAGs. The researcher responsible for thesweet potato genetic improvement programand, Larissa Vendrame reports on the experience she had during the development of Embrapa's first purple-fleshed sweet potato cultivar, scheduled for launch in 2020.
“In five years, we selected the most productive clones, from a universe of 16 BAG accessions, and evaluated each one for characteristics such as resistance to the main diseases and pests, root and post-harvest quality. The selected clone is in the process of obtaining registration with the Ministry of Agriculture”, he explains. She attributes the feat of obtaining a vegetatively propagated cultivar in practically half the time required to the wide genetic variability and the good quality of the genetic materials in the bank.
It is not uncommon for the potential of accesses to be known as they are used. Therefore, it is possible that when searching for a specific characteristic, researchers come across other possibilities. The curator of the lettuce germplasm collection and responsible for the genetic improvement program, Fábio Suinaga, experienced this situation during the development work on curly lettuce cultivars BRS Leila e BRS Mediterrânea, launched in 2018.
The researcher was looking for other characteristics of the curly cultivar when he noticed the heat resistance of one of the materials during the evaluation of the strains in the field. “This characteristic was passed on to BRS Leila by its ‘father’, who was already known for its sources of resistance to soil diseases, for example. It was a gift that we received”, he considers.
Other possibilities present in BAGs are related to the sources of genetic factors to enhance the nutrients in food. The curator of BAG Tomate and responsible for the tomato genetic improvement program, researcher Leonardo Boiteux, cites some examples obtained with enriched hybrids: the tomato BRS Nagai has 25% more vitamin C than others on the market; and the BRS Zamir, from the grape segment, has a content of the antioxidant pigment lycopene of up to 144 µg/g, while other cultivars sold in Brazil obtain around 40 µg/g.
BAG Tomate has around 1,7 accessions, with some of the wild materials having double the lycopene content found in the BRS Zamir hybrid. In this universe there are also genetic materials that present fruits with different colors. “Each color is associated with a nutritional composition. The germplasm bank works as a kind of 'bank reserve' of new genes of interest that can be accessed according to the need and the strategy adopted by the institution”, reinforces Boiteux.
Together with researchers in the field of breeding and genetic resources, phytopathologists are constantly testing accessions in search of sources of resistance to diseases and pests. During evaluations of purple-fleshed sweetpotato germplasms, nematology researcher Jadir Pinheiro found an accession with resistance to Meloidogyne enterolobii.
“Among root-knot nematode species, M. enterolobii is the one that presents the greatest difficulty in finding materials with resistance, as it is a highly aggressive species, multiplying and causing damage in genotypes considered resistant to other Meloidogyne species. This identification reinforces the importance of conserving a BAG with great genetic variability”, points out the researcher.
In some cases, desirable characteristics for a cultivar result from crossing accessions. Phytopathologist Carlos Lopes cites the case of BRS Acará – a rootstock for peppers, launched in 2018. He explains that the hybrid has two sources of resistance to soil diseases coming from two genetic materials from BAG Capsicum used at the intersection.
At Embrapa Hortaliças, the majority of genetic materials are preserved ex situ, outside their natural environment and, generally, in the form of seeds kept in cold rooms. This is the case of orthodox seed species – those that remain viable even when dehydrated and subjected to low temperatures – such as pumpkin, eggplant, melon, pepper and tomato.
The curator of the germplasm bank Capsicum, Sabrina de Carvalho, explains that 50 different pepper accessions are multiplied annually and, after characterization, these materials are preserved in seed form, in cold rooms.
Another form of conservation ex situ é in vivo, in the case of vegetatively propagated vegetables, such as garlic, sweet potatoes and parsley, which are kept in screen structures or in the open field. These BAGs, like some others, do not have duplication of material as occurs with BAGs from orthodox seeds, reinforcing the importance of these in vivo banks for maintaining the genetic variability of these species.
The curator of the garlic germplasm bank, researcher Francisco Vilela, explains that, as it does not produce botanical seeds, garlic needs to be constantly multiplied. Every year, 250 plants from each of the 140 accessions go to the field. These genetic materials come from traditional Brazilian planting regions and from several countries, including Central Asia, which is the center of origin of garlic.
“We save the best bulbs so that, the following year, we can select the largest bulbils and replant them. Even so, germplasms have undergone an accelerated process of degeneration due to virus infection, as some of these materials have been in the bank for more than 40 years”, he explains. To reinvigorate the accessions, Vilela says that the germplasms are undergoing a viral cleaning process in the laboratory.
To date, around 60% of BAG materials are virus free and are kept indoors to avoid reinfection by viruses. So much effort is justified. “I cannot say with certainty that we are the only garlic germplasm bank in Brazil, but it is the one with the largest number of preserved genetic resources”, highlights Vilela.
Similar work to garlic is carried out in the sweet potato bank. In a screen, the 240 accessions are duplicated in pots, whose substrates are replaced annually. “The first materials are from the 80s and, considering this maintenance in vivo, there is always the possibility of loss. That's why we are constantly introducing new sources based on donations from producers”, highlights the curator of BAG Batata-Doce, Larissa Vendrame.
Another aspect of germplasm banks and collections is the conservation of varieties cultivated in different Brazilian regions. Thanks to this function of BAGs, the garlic producing regions of Rio Grande do Norte and Piauí are rescuing the tradition left aside due to the loss of genetic material. An agreement signed between Embrapa Hortaliças, Sebrae and municipal bodies made it possible for farmers in these two states to rescue the Alho Branco Mineiro cultivar..
According to researcher Francisco Vilela, producers lost this variety due to virus infection. “Embrapa’s contribution to these revitalization projects is to return to the producing regions the varieties lost by producers over time, with the difference of being virus-free. We deliver the improved cultivar and enable them to once again use the variety that is part of the region’s history”, highlights Vilela.
The rescue of a food tradition was also experienced by Indian Cecília Awaeko, from the Apalai ethnic group, during an event held in 2017, at Embrapa Hortaliças, on conservation and use of genetic resources. She “rediscovered” the Guariba sweet potato that her tribe ended up losing over time.
Carrying out all activities carried out in a BAG – collection, exchange, conservation, multiplication, characterization, evaluation, documentation and use – requires a quality standard. Recently, Embrapa Hortaliças, through BAG de Capsicum, participated in the corporate project “QUALIVEG – Implementation and Monitoring of Quality Systems in the Vegetable Area”.
BAG curator, Sabrina de Carvalho, explains that Embrapa's objective is to achieve this quality standard in all plant resource banks, also providing traceability to the results. “It is a detailed work that involves everything from adequate facilities and environmental conditions to the identification of packaging for seed conservation, in addition to the standardization of procedures for the activities carried out in the BAGs and the training of employees”, she concludes.
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