August 18, 2022

Scientists use wild species to improve cassava

searching from Embrapa Cassava and Fruticulture (BA) they use wild cassava species To promote the genetic improvement of the rootstock.

In these little-known, generally inedible cultivars, genes of importance for agricultural production related to traits of agricultural interest such as productivity, disease resistance, and high starch content (a characteristic required by industry) are mined.

This work is part of so-called pre-breeding that aims to identify beneficial traits in accessions that are not well adapted to local soil and climatic conditions, and to make these genes available in more adapted genotypes, with good agronomic characteristics, so that they can be introduced into a breeding programme.

“Pre-breeding procedures focus primarily on the discovery of beneficial alleles for agriculturally important traits of interest to farmers, such as pest and disease resistance, root yield and starch, traits associated with root quality, and pulp characteristics that are traits for each starch that has and determines its industrial applications,” he explains. Researcher Edir Jorge Oliveira, breeder in Embrapa.

two decades of research

For nearly 20 years, one of the projects led by Scholar Alfredo Augusto Cunha Elvis in partnership with International Center for Tropical Agriculture (Ciat), Colombiasought to explore the potential of wild cassava species in terms of resistance to major pests and diseases (biotic stresses), as well as tolerance to drought and post-harvest physiological degradation (abiotic stresses).

We have been able to ensure that wild species are sources of genes that can be used in a breeding programme. Alves says they have a lot of variety when compared to our commercial cassava.

The introduction of wild species of the genus Manihot into the research unit in Bahia began in 2005, with plant seeds of several species transferred from Embrapa Genetic Resources and Biotechnology (DF) and collection expeditions conducted in semi-arid regions and Cerrado. Today there are about 60,000 seeds of 14 species of Manihot.

“The genus Manihot, which is the same as the commercial cassava genus, has 99 species. Taxonomists claim that 75% of the biodiversity of the genus is in Brazil. Therefore, we are the main center of origin for this species”, he continues.

“To make hybrids between commercial and wild species, the seeds must germinate, and the plant has to flower and produce new hybrid seeds. However, commercial varieties usually have a low flowering rate. In addition, the female flower opens in front of the male flower, which It makes flowering synchronization more difficult. Hence the importance of the studies for inducing commercial cassava flowering, which is the focus of the NextGen Improvement Project, led by Eder Oliveira,” according to Alves’ report.

An example is Manihot flabellifolia, which is used in cross-breeding with commercial cultivars in order to obtain cultivars resistant to the whitefly Aleurothrixus aepim. The main pests of cassava cultivation are the whitefly, which are sap-sucking insects, thus impairing and harming plant growth, affecting the production and quality of roots.

keep

The largest cassava germplasm bank (BAG) in Brazil is located in Embrapa unit in Cruz das Almas (BA). There are 1,540 conserved accessions in the field (with ten plants per strain), and an effort has been made to obtain a copy of this genetic material in the laboratory: 650 accessions were made in vitro in the tissue culture laboratory, under the responsibility of researcher Antonio da Silva Souza and his team.

“Brazil is a signatory to the International Treaty on Plant Genetic Resources for Food and Agriculture (TIRFAA), which allows countries to make their native varieties available to other signatories, and cassava was the first product Brazil made available in this treaty,” explains researcher Vanderlei da Silva Santos, breeder and BAG curator Cassava. This exchange is mediated by Embrapa Genetic Resources and Biotechnology (DF), which sends the required materials into the laboratory.

Partnership with the product

Since the early 1990s, as an ally of traditional research, The program uses a participatory methodology that includes family farmers, indigenous people, and quilombolasIt has become an effective tool for raising the level of adoption and dissemination of the resulting cultivars, accelerating their incorporation by producers and expanding the genetic diversity of cassava in crops.

Recently, with the increasing importance of using cassava for industrial purposes, partnerships with the private sector have also included major root producers and starch industries, particularly in the center and south of the country. The program develops varieties that are added to the liberated table manioc with high nutritional quality and good preservation after harvest, and are used in the processing of products with high added value.

Contrary to the saying “Casa de ferreiro, espeto de pau”, there are two distinct agro-industries: the Dois Irmãos beijus production unit, in the rural Cruz das Almas, and very close to Embrapa Mandioca e Fruticultura. Community Earring Association (Abrinco), in the municipality of Maragogipe.

Once he began producing the colorful beige he learned from researcher Joselito da Silva Motta and repaired the physical structure of Dois Irmãos, José Carlos Mendonça began providing them with school lunches through the Food Acquisition Program (PAA) – as well as for sale in his box at the municipal market. Today, the entrepreneur employs 17 people and sells 5,000 packages a week to bakeries, grocery stores and supermarkets in Recôncavo and the Metropolitan Region of Salvador. “We work from Monday to Friday, from 7 am to 12 pm and from 1 pm to 5 pm, but we cannot keep up with the demand. Little by little we will expand,” he says.

On the other hand, Abrinko is exploring another niche and has a diverse menu of products with the stamp of family farming: cassava paste, chilled cassava, cassava peeled, tapioca gum for bijoux, granulated tapioca and cassava flour. After training in processing and good manufacturing practices in the Food Science and Technology Laboratory, the association sends about 19 tons per month to Recôncavo, Salvador and Lauro de Freitas, with the possibility of increasing production to 40 tons per month.