Genetics increases carioca bean productivity by a third

Over the last 40 years, Brazil has reduced its bean planted area by 30%, even so, production in the period increased by 35%, reaching three million tons today. This gain is due to the increase in crop productivity, which is partly attributed to the use of new varieties. In the case of carioca beans, the most cultivated in the country, an increase in grain productivity of 0,72% is estimated, an increase of 17 kilos per hectare per year exclusively due to the use of genetically superior plants.

This information is from a study of Embrapa which evaluated the efficiency of its bean breeding program and is based on the calculation of genetic progress with the crop. This is an indicator that correlates agronomic characteristics such as productivity, and methods used for the selection, crossing and advancement of generations of plants (lineages). Considering the entire study period of 22 years, the increase in productivity represents an accumulated increase of 380 kilos per hectare, or the equivalent of practically a third of the national average productivity, which is 1.354 kilos per hectare.

According to the researcher who led this project, Luis Claudio de Faria, who works in Embrapa's bean breeding program in Aracaju (SE), genetic progress was estimated in a series of experiments in the field, in conjunction with institutions partners, in four producing regions (South, Southeast, Central-West and Northeast), covering 20 different environments, three sowing seasons (water, dry and winter) and using a database with 22 years of information on strains and varieties.

“As the study was conducted with repetitions and in several field trials, it was possible to more faithfully represent the interaction conditions between the genotypes and the different growing environments; and make a consistent estimate of the average genetic progress for grain productivity, using the direct method, allowing very precise results to be achieved”, says Faria.

Unprecedented estimate in Brazil

The estimate of genetic progress for grain productivity in the carioca bean crop in Brazil is unprecedented, as it has never been considered at a national level, taking into account the main producing regions of the country. This was only possible thanks to the program's connection of improvement from Embrapa to the network of state research institutions, which supported the initiative. On a regional basis, many of these institutions have already carried out similar studies and reached similar results (see below).

Bean quality also improved

In addition to productivity, the genetic progress estimate for carioca beans also showed a significant gain of 2,37% per year in grain quality. This is related to aspects valued by the consumer and the industry, such as cooking time, color of the bean broth, non-darkening of the packaged product and yield of whole grains during processing.

According to Faria, the study of genetic progress also served to verify whether adjustments were needed in the direction of the carioca bean breeding program, in order to improve its performance. “Genetic progress in the two most important characteristics, productivity and grain quality, shows that the path followed is in the desired direction and that, at least for now, it is not necessary to adopt any corrective measures”, he believes.

Despite this, he cited aspects that need to be adjusted. “Selection for grain productivity generated some unfavorable results for upright plant architecture and tolerance to lodging (the tendency of the plant to lie on the ground). As a result, the most productive strains do not necessarily represent progress for these other two variables as well,” states Faria.

He clarifies that this happens because the association between productivity and erect plant architecture and tolerance to lodging was only recently realized in lineages from the Rio group. And this is an example of a challenge for the improvement program in the coming years.

The study on the genetic progress of the carioca bean improvement program in Brazil was coordinated by researchers from Embrapa Rice and Beans (GO), Embrapa Corn and Sorghum (MG) and Embrapa Coastal Tabuleiros (SE); and by professors from the Federal University of Goiás (UFG)and the Higher School of Agricultural Sciences of Rio Verde (GO).

Embrapa has already launched more than 20 cultivars of carioca beans for the country. The legume is cultivated throughout the year by small, medium and large producers, in subtropical and tropical ecosystems, such as Cerrados, Atlantic Forest and Semiarid, in varied arrangements of plants, in monoculture or intercropped planting. The product is in the Brazilian diet and is, admittedly, an excellent source of protein. Brazil is one of the largest bean producing and consuming countries alongside India, Myanmar, China, the United States and Mexico.  

Impact of varieties

The estimate of genetic progress for carioca beans in 22 years represents the progress achieved by the efficiency of the breeding program, considering methods of selection, crossing and advancement of plant generations. For the production sector, the most noticeable contribution of this process is the impact caused by the varieties launched. In this case, the repercussion is not just the use of superior genetics, but rather its interaction with local conditions of the cultivation environment and crop management.  

Agricultural engineer and rural producer in Planaltina (DF) Hélio Dal Bello has been planting beans for over 50 years and is one of the farmers who uses improved varieties and who has witnessed the impact caused by the spread of new cultivars. “Throughout my experience, I have noticed great improvements in productivity and resistance to diseases, especially anthracnose. Crops today are, without a doubt, much healthier than in the past. Today, the Rio de Janeiro grain also has a greater durability of its light color, it does not darken quickly, and is therefore a product valued by the industry. Another important aspect is that the plant cycle has decreased, the cultivars have become more precocious”, said the producer.

In addition to these impacts, Dal Bello considered some elements that could be improved in the future for the new varieties, including the root system. “It would be good to have plants that are more resistant to soil fungi, such as fusarium, which is one of the problems I face”, said the farmer.

For this 2017/2018 summer harvest, Dal Bello sowed 950 hectares with legumes and BRS Style (of the Rio de Janeiro grain type) is one of the Embrapa cultivars that was used, with an expected yield of approximately 2.500 kilos per hectare.