Embrapa scientists developed an innovative cassava propagation process. Instead of using traditional material (seed stems), the new technique uses mini cuttings. The innovation managed to overcome undesirable characteristics, such as the low propagation rate and large volumes of conventional planting materials, which complicate the logistics for storing and transporting the stalks to new areas.
The technique, developed within the scope of the Network for multiplication and transfer of cassava seed stalks with genetic and phytosanitary quality (Reniva), is the subject of the technical statement "Cassava mini-stacks - new alternative planting material", signed by the Embrapa team Cassava and Fruit Culture (BA), technicians and partner producers. Agronomist Herminio Rocha, one of the coordinators of Reniva, says that this technique emerged from the work, also unprecedented, of multiplying cassava seedlings on a large scale at the Instituto Biofábrica de Cacau (today Biofábrica da Bahia), partner of Reniva.
Main advantage: transportation
Rocha remembers that conventional cassava planting material requires logistics that are very well linked to field operations. “When you think about planting areas larger than 10 ha, you think about many trucks of handles. To plant just 1 ha of cassava, 4 m3 to 6 m3 of conventional stalks are required, a large volume. When you think about planting with mini cuttings, you reduce this too much. A conventional handle weighs approximately 45 g; a mini cutting, about a tenth of that [5 g].” Benedito Dutra Souza, producer from Tracuateua, in the municipality of Pará, partner of Rede Reniva, reiterates that this is the great “gain” of the mini-stake. “To transport a large volume of seed cassava from one state to another, we need trailers and carts. In the case of mini stakes, we can take them in cars,” compares the producer.
Furthermore, Dutra highlights that the producer should use minicutting as a strategy to have access to different cultivars. And he leaves a message: “We rural producers made a big mistake. We want someone to make the seed pods for us. What we have to do is have access to the cultivar we want and plant it on our property. Here is the recommendation for producers who want to plant 100 hectares to produce roots: that they plant four hectares of mini cuttings. A well-organized 1 ha clonal garden produces 12 mini cuttings in 400 months. So can you imagine a producer who has 4 ha of minicuttings there? It’s a lot of material.” Excitedly, he says he hopes to find boxes of these materials to sell in agricultural products stores in the near future.
Innovation generating innovation
The production capacity of the biofactory at the beginning of the Reniva Network, in 2011, according to the Embrapa agronomist, was quite significant. However, after in vitro establishment, the first seedlings began to be acclimatized and this meant that a large volume of batches were acclimatized at the same time. From one moment to the next, there were approximately 500 micropropagated seedlings in the biofactory, of several different genotypes, ready to be delivered to maniveros, as seed cassava producers are called (a figure in the cassava production chain created by Reniva).
“The network was something new, the logistics of distributing the seedlings were not so well planned with the agencies that could receive them. This caused them to be retained in the nurseries for longer than necessary. And, when the seedling does not emerge, it suffers from what is called etiolation. Plant tissue, which seeks light, grows excessively. The stems become quite large, measuring more than 1,20 m in height. The only solution we had to avoid destroying seedlings in large volumes was to cut the aerial part and the seedlings would begin to resprout. But we realized that the material that we cut so valuable, with guaranteed plant health and proven genetic identity, was being neglected. And there were gems there, that is, it had the capacity to generate plants”, describes Rocha.
From there, it was decided to cut the stems into three or four pieces, the approximate size of a pencil (10 cm to 12 cm), containing, according to the agronomist, two to four buds in each segment. “We noticed that, after a few days, the buds started to sprout. So why not plant this material in the field and see what its agronomic behavior would be in terms of root production?”, he says.
The discovery of minipiles
Rocha explains that the rods were divided into four parts. The basal part is always the most woody, that is, with a more advanced physiological age, a rustified piece more similar to a conventional stem. The parts of the middle and upper thirds and the tip are more tender, juvenile. Field tests proved that the base behaved exactly the same as a conventional stem, producing a plant similar to that which emerges from a normal stem, which awakened in the team the possibility of using the acclimatization phase in the nurseries for production not only from seedlings, but also from minicuttings.
The agronomist says that another advantage is the total use of the material. “From the moment you harvest the minicutting, the remainder of the stem, which is in the juvenile stage and does not behave exactly like a conventional cutting, is not discarded, it is replanted in the tubes, producing more seedlings. So this acclimatization phase does not disregard absolutely anything that sprouts from the seedlings being acclimatized”, he points out. Hence the idea of carrying out larger tests in the field. In 2017, quantities of mini-cuttings in Styrofoam boxes were sent to producer Benedito Dutra Souza, in Pará.
From disbelief to technology diffuser
“When those mini cassava cuttings arrived, very small in a Styrofoam box, I confess that I looked at them with great suspicion. If I weren't an agronomist, if I were just a rural producer, it's very likely that I wouldn't have planted. But this changed my vision as an agronomist, as a businessman, there was a watershed moment there,” says Dutra about his experience with minicuttings.
The producer says that the first thing he did was weigh the material. According to him, 15 g were recorded in total, just three grams per piece. “I recorded this moment because it would be a justification to show that they did not germinate because they were small. I thought it was going to go wrong. I planted it without believing it. My field assistant didn’t want to plant it, but I went ahead.”
Following technical recommendations, Dutra used a spacing of 1 m x 80 cm, and, after 25 days, he realized that the plants would develop. “At 11 months, I chose the best plant and started it. We had cassavas with an average size of 17 cm, weighing around 100 g, remembering that the mini cassava that gave rise was one weighing 3 g. We managed to extract around 17 normal seed plants from this plant, measuring 17 to 20 cm, which is the standard used here, and a diameter of 2 cm on average. I sent it to the researchers. Then I was already aware that it was possible to easily produce roots and produce a new plant.”
And he points out the strategy for the production of minipiles. According to the producer, the mini wood cuttings, once planted with a density of approximately ten thousand plants per hectare, that is, with a spacing of 1 m x 1 m, will produce roots and a normal plant, which, in turn, will generate new cuttings- seed. “In order for us to produce minicuttings from minicuttings, here comes the question: we have to plant at least 30 thousand minicuttings per hectare, with a spacing of approximately 1 m x 30 cm. In other words, what allows me to produce mini-cuttings is not whether I am planting mini-cuttings, it is the densification”, he reveals.
Dutra is an anchor handler, the first in Pará, and has already been distributing conventional handles to other states in the North and Northeast and small quantities of mini piles for testing. “Our role as handler is very interesting. We are the link between research and the producer who wants the material, and the minipiles will allow us to produce large volumes in a short space of time.”
Interest from African countries
“What initially appeared as a problem became a solution. Those etiolated seedlings became this technological advent of great impact on the cassava production system, especially in African countries, where 95% of cassava production is carried out by family farming, producers who have difficulties in logistics of planting material, obtaining , distribution and transportation of these materials,” highlights Rocha. He informs that this work, presented in 2018 during the largest cassava congress in the world, the Global Cassava Partnership for the XXI Century (GCP-21), in Benin, aroused the interest of researchers in Nigeria, today the largest producing and consuming country of cassava in the world, which started to adopt the new material.
There are three different approaches to the production of mini cassava cuttings: the first is based on the acclimatization of seedlings micropropagated in a nursery; the second is from seedlings planted in the field; and, the third, through the rapid multiplication technique. The step-by-step process for each is described in the publication.
The experience of the extreme south of Bahia
Minicuts were also taken for testing in the extreme south of Bahia, through the participation of Embrapa Cassava and Fruticulture in the Territorial Action Plan (PAT) for Mandioculture in the Extreme South of Bahia, which involves ten municipalities. Reniva arrived to fill a gap in the region: the lack of variety. Around 68 thousand seedlings from the Bahia Biofactory were distributed to the 20 maniveiros installed in the territory. PAT also created the figure of the maniveiro-guardian, in the community of Canabrava, in Alcobaça, where 23 varieties from the biofactory were planted for evaluation. Two stood out: BRS Formosa and Corrente, traditional from the Laje region (BA).
“That was the initial purpose: validation of new varieties and local distribution. But we have already managed to sell 40 cubic meters of seed cassava to a company in Minas Gerais. A truck left here in December last year. It was a milestone from the point of view of starting the propagation and commercialization of this material”, says agricultural engineer Jeilly Vivianne Ribeiro, technical coordinator of PAT, which brings together more than 40 partners, being led by Banco do Nordeste and Suzano.
Regarding the mini-cutting technology, Ribeiro says that the producer who received the mini-cuttings for testing had the same reaction as Dutra Souza. “255 mini stakes arrived in a shoe box. He said: ‘we are planting it because you want it, but we don’t believe it will work’. Afterwards we went back there with the Embrapa team, who saw what the area looked like. There is no difference in areas planted with conventional material,” he reports.
The agronomist informs that PAT implemented a minicutting production field in April, and the expectation is to have the first harvest by the end of the year. The planting was very dense (50 cm x 30 cm) — the traditional size is 1 m x 1 m — for the development of minicuttings.
Reniva in the country
Presented in 2011 to the Sectoral Chamber of the Cassava and Derivatives Production Chain of Bahia, the project became one of the priorities in the strategic planning of this forum, being taken over by the government of the State of Bahia. In May 2012, the technical cooperation agreement between the partners was signed in Vitória da Conquista (BA).
It started with 16 territories in the State of Bahia, today it is concentrated in 11. Since the beginning, 900 thousand seedlings have been delivered by Biofábrica da Bahia. Due to problems with technical assistance in the state, aggravated by the extinction of the Bahian Agricultural Development Company (EBDA), work with handlers was hampered. In the beginning, there were 36, five remained, but in 2016 the 20 from PAT entered the network. Each maniveiro plants 13 thousand seedlings in 1 ha, with irrigation throughout the entire process.
Over this time, Reniva has been spreading throughout the country. In addition to Pará, today it is also present in Araripina (PE) and Salinas (North of Minas), through multi-institutional arrangements promoted by Agronordeste, an action plan prepared by federal government to boost the sustainable economic and social development of rural areas in the region.
There are also initiatives in Maranhão with Ambev, which is interested in cassava roots for processing and manufacturing beer. In Ceará, with resources from a parliamentary amendment, a rapid multiplication unit was installed in the Embrapa experimental field in Barbalha. In Tocantins, the actions are led by Embrapa Pesca e Aquicultura. There are other initiatives in these states mentioned and also in Amazonas, Rio Grande do Norte, Paraíba, São Paulo, Mato Grosso do Sul, Paraná and Santa Catarina.
“Reniva is increasingly becoming what we need it to be, a network, evolving towards autonomy in many places. More and more interested parties understand that they need to develop their efforts within common principles, but with independence to make better use of their potential and thus ensure that advances are disseminated more easily, because each one already has an arrangement made according to their needs. and possibilities”, analyzes the agricultural engineer at Embrapa Mandioca e Fruticultura Helton Fleck, who shares the coordination of the network with Herminio Rocha. Alessandra Vale
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